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CONFIG_MODULE_COMPRESS is only used to activate the choice for module
compression algorithm. It will be simpler to make the choice always
visible, and add CONFIG_MODULE_COMPRESS_NONE in the choice.
This is more consistent with the "Kernel compression mode" and "Built-in
initramfs compression mode" choices. CONFIG_KERNEL_UNCOMPRESSED and
CONFIG_INITRAMFS_COMPRESSION_NONE are available to choose no compression.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Documentation/process/changes.rst defines the minimum assembler version
(binutils version), but we have never checked it in the build time.
Kbuild never invokes 'as' directly because all assembly files in the
kernel tree are *.S, hence must be preprocessed. I do not expect
raw assembly source files (*.s) would be added to the kernel tree.
Therefore, we always use $(CC) as the assembler driver, and commit
aa824e0c962b ("kbuild: remove AS variable") removed 'AS'. However,
we are still interested in the version of the assembler acting behind.
As usual, the --version option prints the version string.
$ as --version | head -n 1
GNU assembler (GNU Binutils for Ubuntu) 2.35.1
But, we do not have $(AS). So, we can add the -Wa prefix so that
$(CC) passes --version down to the backing assembler.
$ gcc -Wa,--version | head -n 1
gcc: fatal error: no input files
compilation terminated.
OK, we need to input something to satisfy gcc.
$ gcc -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1
GNU assembler (GNU Binutils for Ubuntu) 2.35.1
The combination of Clang and GNU assembler works in the same way:
$ clang -no-integrated-as -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1
GNU assembler (GNU Binutils for Ubuntu) 2.35.1
Clang with the integrated assembler fails like this:
$ clang -integrated-as -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1
clang: error: unsupported argument '--version' to option 'Wa,'
For the last case, checking the error message is fragile. If the
proposal for -Wa,--version support [1] is accepted, this may not be
even an error in the future.
One easy way is to check if -integrated-as is present in the passed
arguments. We did not pass -integrated-as to CLANG_FLAGS before, but
we can make it explicit.
Nathan pointed out -integrated-as is the default for all of the
architectures/targets that the kernel cares about, but it goes
along with "explicit is better than implicit" policy. [2]
With all this in my mind, I implemented scripts/as-version.sh to
check the assembler version in Kconfig time.
$ scripts/as-version.sh gcc
GNU 23501
$ scripts/as-version.sh clang -no-integrated-as
GNU 23501
$ scripts/as-version.sh clang -integrated-as
LLVM 0
[1]: https://github.com/ClangBuiltLinux/linux/issues/1320
[2]: https://lore.kernel.org/linux-kbuild/20210307044253.v3h47ucq6ng25iay@archlinux-ax161/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Now "modules" is the only member of the "option" property.
Remove "option", and move "modules" to the top level property.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
allnoconfig_y is an ugly hack that sets a symbol to 'y' by allnoconfig.
allnoconfig does not mean a minimal set of CONFIG options because a
bunch of prompts are hidden by 'if EMBEDDED' or 'if EXPERT', but I do
not like to hack Kconfig this way.
Use the pre-existing feature, KCONFIG_ALLCONFIG, to provide a one
liner config fragment. CONFIG_EMBEDDED=y is still forced when
allnoconfig is invoked as a part of tinyconfig.
No change in the .config file produced by 'make tinyconfig'.
The output of 'make allnoconfig' will be changed; we will get
CONFIG_EMBEDDED=n because allnoconfig literally sets all symbols to n.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
"defconfig_list" is a weird option that defines a static symbol that
declares the list of base config files in case the .config does not
exist yet.
This is quite different from other normal symbols; we just abused the
"string" type and the "default" properties to list out the input files.
They must be fixed values since these are searched for and loaded in
the parse stage.
It is an ugly hack, and should not exist in the first place. Providing
this feature as an environment variable is a saner approach.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
The kernel build process currently only signs kernel modules when
MODULE_SIG is enabled. Also, sign the kernel modules at build time when
IMA_APPRAISE_MODSIG is enabled.
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This change adds support for Clang’s forward-edge Control Flow
Integrity (CFI) checking. With CONFIG_CFI_CLANG, the compiler
injects a runtime check before each indirect function call to ensure
the target is a valid function with the correct static type. This
restricts possible call targets and makes it more difficult for
an attacker to exploit bugs that allow the modification of stored
function pointers. For more details, see:
https://clang.llvm.org/docs/ControlFlowIntegrity.html
Clang requires CONFIG_LTO_CLANG to be enabled with CFI to gain
visibility to possible call targets. Kernel modules are supported
with Clang’s cross-DSO CFI mode, which allows checking between
independently compiled components.
With CFI enabled, the compiler injects a __cfi_check() function into
the kernel and each module for validating local call targets. For
cross-module calls that cannot be validated locally, the compiler
calls the global __cfi_slowpath_diag() function, which determines
the target module and calls the correct __cfi_check() function. This
patch includes a slowpath implementation that uses __module_address()
to resolve call targets, and with CONFIG_CFI_CLANG_SHADOW enabled, a
shadow map that speeds up module look-ups by ~3x.
Clang implements indirect call checking using jump tables and
offers two methods of generating them. With canonical jump tables,
the compiler renames each address-taken function to <function>.cfi
and points the original symbol to a jump table entry, which passes
__cfi_check() validation. This isn’t compatible with stand-alone
assembly code, which the compiler doesn’t instrument, and would
result in indirect calls to assembly code to fail. Therefore, we
default to using non-canonical jump tables instead, where the compiler
generates a local jump table entry <function>.cfi_jt for each
address-taken function, and replaces all references to the function
with the address of the jump table entry.
Note that because non-canonical jump table addresses are local
to each component, they break cross-module function address
equality. Specifically, the address of a global function will be
different in each module, as it's replaced with the address of a local
jump table entry. If this address is passed to a different module,
it won’t match the address of the same function taken there. This
may break code that relies on comparing addresses passed from other
components.
CFI checking can be disabled in a function with the __nocfi attribute.
Additionally, CFI can be disabled for an entire compilation unit by
filtering out CC_FLAGS_CFI.
By default, CFI failures result in a kernel panic to stop a potential
exploit. CONFIG_CFI_PERMISSIVE enables a permissive mode, where the
kernel prints out a rate-limited warning instead, and allows execution
to continue. This option is helpful for locating type mismatches, but
should only be enabled during development.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210408182843.1754385-2-samitolvanen@google.com
This provides the ability for architectures to enable kernel stack base
address offset randomization. This feature is controlled by the boot
param "randomize_kstack_offset=on/off", with its default value set by
CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT.
This feature is based on the original idea from the last public release
of PaX's RANDKSTACK feature: https://pax.grsecurity.net/docs/randkstack.txt
All the credit for the original idea goes to the PaX team. Note that
the design and implementation of this upstream randomize_kstack_offset
feature differs greatly from the RANDKSTACK feature (see below).
Reasoning for the feature:
This feature aims to make harder the various stack-based attacks that
rely on deterministic stack structure. We have had many such attacks in
past (just to name few):
https://jon.oberheide.org/files/infiltrate12-thestackisback.pdfhttps://jon.oberheide.org/files/stackjacking-infiltrate11.pdfhttps://googleprojectzero.blogspot.com/2016/06/exploiting-recursion-in-linux-kernel_20.html
As Linux kernel stack protections have been constantly improving
(vmap-based stack allocation with guard pages, removal of thread_info,
STACKLEAK), attackers have had to find new ways for their exploits
to work. They have done so, continuing to rely on the kernel's stack
determinism, in situations where VMAP_STACK and THREAD_INFO_IN_TASK_STRUCT
were not relevant. For example, the following recent attacks would have
been hampered if the stack offset was non-deterministic between syscalls:
https://repositorio-aberto.up.pt/bitstream/10216/125357/2/374717.pdf
(page 70: targeting the pt_regs copy with linear stack overflow)
https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html
(leaked stack address from one syscall as a target during next syscall)
The main idea is that since the stack offset is randomized on each system
call, it is harder for an attack to reliably land in any particular place
on the thread stack, even with address exposures, as the stack base will
change on the next syscall. Also, since randomization is performed after
placing pt_regs, the ptrace-based approach[1] to discover the randomized
offset during a long-running syscall should not be possible.
Design description:
During most of the kernel's execution, it runs on the "thread stack",
which is pretty deterministic in its structure: it is fixed in size,
and on every entry from userspace to kernel on a syscall the thread
stack starts construction from an address fetched from the per-cpu
cpu_current_top_of_stack variable. The first element to be pushed to the
thread stack is the pt_regs struct that stores all required CPU registers
and syscall parameters. Finally the specific syscall function is called,
with the stack being used as the kernel executes the resulting request.
The goal of randomize_kstack_offset feature is to add a random offset
after the pt_regs has been pushed to the stack and before the rest of the
thread stack is used during the syscall processing, and to change it every
time a process issues a syscall. The source of randomness is currently
architecture-defined (but x86 is using the low byte of rdtsc()). Future
improvements for different entropy sources is possible, but out of scope
for this patch. Further more, to add more unpredictability, new offsets
are chosen at the end of syscalls (the timing of which should be less
easy to measure from userspace than at syscall entry time), and stored
in a per-CPU variable, so that the life of the value does not stay
explicitly tied to a single task.
As suggested by Andy Lutomirski, the offset is added using alloca()
and an empty asm() statement with an output constraint, since it avoids
changes to assembly syscall entry code, to the unwinder, and provides
correct stack alignment as defined by the compiler.
In order to make this available by default with zero performance impact
for those that don't want it, it is boot-time selectable with static
branches. This way, if the overhead is not wanted, it can just be
left turned off with no performance impact.
The generated assembly for x86_64 with GCC looks like this:
...
ffffffff81003977: 65 8b 05 02 ea 00 7f mov %gs:0x7f00ea02(%rip),%eax
# 12380 <kstack_offset>
ffffffff8100397e: 25 ff 03 00 00 and $0x3ff,%eax
ffffffff81003983: 48 83 c0 0f add $0xf,%rax
ffffffff81003987: 25 f8 07 00 00 and $0x7f8,%eax
ffffffff8100398c: 48 29 c4 sub %rax,%rsp
ffffffff8100398f: 48 8d 44 24 0f lea 0xf(%rsp),%rax
ffffffff81003994: 48 83 e0 f0 and $0xfffffffffffffff0,%rax
...
As a result of the above stack alignment, this patch introduces about
5 bits of randomness after pt_regs is spilled to the thread stack on
x86_64, and 6 bits on x86_32 (since its has 1 fewer bit required for
stack alignment). The amount of entropy could be adjusted based on how
much of the stack space we wish to trade for security.
My measure of syscall performance overhead (on x86_64):
lmbench: /usr/lib/lmbench/bin/x86_64-linux-gnu/lat_syscall -N 10000 null
randomize_kstack_offset=y Simple syscall: 0.7082 microseconds
randomize_kstack_offset=n Simple syscall: 0.7016 microseconds
So, roughly 0.9% overhead growth for a no-op syscall, which is very
manageable. And for people that don't want this, it's off by default.
There are two gotchas with using the alloca() trick. First,
compilers that have Stack Clash protection (-fstack-clash-protection)
enabled by default (e.g. Ubuntu[3]) add pagesize stack probes to
any dynamic stack allocations. While the randomization offset is
always less than a page, the resulting assembly would still contain
(unreachable!) probing routines, bloating the resulting assembly. To
avoid this, -fno-stack-clash-protection is unconditionally added to
the kernel Makefile since this is the only dynamic stack allocation in
the kernel (now that VLAs have been removed) and it is provably safe
from Stack Clash style attacks.
The second gotcha with alloca() is a negative interaction with
-fstack-protector*, in that it sees the alloca() as an array allocation,
which triggers the unconditional addition of the stack canary function
pre/post-amble which slows down syscalls regardless of the static
branch. In order to avoid adding this unneeded check and its associated
performance impact, architectures need to carefully remove uses of
-fstack-protector-strong (or -fstack-protector) in the compilation units
that use the add_random_kstack() macro and to audit the resulting stack
mitigation coverage (to make sure no desired coverage disappears). No
change is visible for this on x86 because the stack protector is already
unconditionally disabled for the compilation unit, but the change is
required on arm64. There is, unfortunately, no attribute that can be
used to disable stack protector for specific functions.
Comparison to PaX RANDKSTACK feature:
The RANDKSTACK feature randomizes the location of the stack start
(cpu_current_top_of_stack), i.e. including the location of pt_regs
structure itself on the stack. Initially this patch followed the same
approach, but during the recent discussions[2], it has been determined
to be of a little value since, if ptrace functionality is available for
an attacker, they can use PTRACE_PEEKUSR/PTRACE_POKEUSR to read/write
different offsets in the pt_regs struct, observe the cache behavior of
the pt_regs accesses, and figure out the random stack offset. Another
difference is that the random offset is stored in a per-cpu variable,
rather than having it be per-thread. As a result, these implementations
differ a fair bit in their implementation details and results, though
obviously the intent is similar.
[1] https://lore.kernel.org/kernel-hardening/2236FBA76BA1254E88B949DDB74E612BA4BC57C1@IRSMSX102.ger.corp.intel.com/
[2] https://lore.kernel.org/kernel-hardening/20190329081358.30497-1-elena.reshetova@intel.com/
[3] https://lists.ubuntu.com/archives/ubuntu-devel/2019-June/040741.html
Co-developed-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210401232347.2791257-4-keescook@chromium.org
The Miscellaneous cgroup provides the resource limiting and tracking
mechanism for the scalar resources which cannot be abstracted like the
other cgroup resources. Controller is enabled by the CONFIG_CGROUP_MISC
config option.
A resource can be added to the controller via enum misc_res_type{} in
the include/linux/misc_cgroup.h file and the corresponding name via
misc_res_name[] in the kernel/cgroup/misc.c file. Provider of the
resource must set its capacity prior to using the resource by calling
misc_cg_set_capacity().
Once a capacity is set then the resource usage can be updated using
charge and uncharge APIs. All of the APIs to interact with misc
controller are in include/linux/misc_cgroup.h.
Miscellaneous controller provides 3 interface files. If two misc
resources (res_a and res_b) are registered then:
misc.capacity
A read-only flat-keyed file shown only in the root cgroup. It shows
miscellaneous scalar resources available on the platform along with
their quantities::
$ cat misc.capacity
res_a 50
res_b 10
misc.current
A read-only flat-keyed file shown in the non-root cgroups. It shows
the current usage of the resources in the cgroup and its children::
$ cat misc.current
res_a 3
res_b 0
misc.max
A read-write flat-keyed file shown in the non root cgroups. Allowed
maximum usage of the resources in the cgroup and its children.::
$ cat misc.max
res_a max
res_b 4
Limit can be set by::
# echo res_a 1 > misc.max
Limit can be set to max by::
# echo res_a max > misc.max
Limits can be set more than the capacity value in the misc.capacity
file.
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: David Rientjes <rientjes@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Strictly speaking, seccomp filters are only used
when CONFIG_SECCOMP_FILTER.
This patch fixes the condition to enable "Seccomp_filters"
in /proc/$pid/status.
Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
Fixes: c818c03b661c ("seccomp: Report number of loaded filters in /proc/$pid/status")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/OSBPR01MB26772D245E2CF4F26B76A989F5669@OSBPR01MB2677.jpnprd01.prod.outlook.com
Parameter "cmdline" has no use, drop it.
Link: https://lkml.kernel.org/r/20210311085213.27680-1-jojing64@gmail.com
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Cao jin <jojing64@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Merge misc fixes from Andrew Morton:
"28 patches.
Subsystems affected by this series: mm (memblock, pagealloc, hugetlb,
highmem, kfence, oom-kill, madvise, kasan, userfaultfd, memcg, and
zram), core-kernel, kconfig, fork, binfmt, MAINTAINERS, kbuild, and
ia64"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (28 commits)
zram: fix broken page writeback
zram: fix return value on writeback_store
mm/memcg: set memcg when splitting page
mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument
ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign
ia64: fix ia64_syscall_get_set_arguments() for break-based syscalls
mm/userfaultfd: fix memory corruption due to writeprotect
kasan: fix KASAN_STACK dependency for HW_TAGS
kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
mm/madvise: replace ptrace attach requirement for process_madvise
include/linux/sched/mm.h: use rcu_dereference in in_vfork()
kfence: fix reports if constant function prefixes exist
kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations
kfence: fix printk format for ptrdiff_t
linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP*
MAINTAINERS: exclude uapi directories in API/ABI section
binfmt_misc: fix possible deadlock in bm_register_write
mm/highmem.c: fix zero_user_segments() with start > end
hugetlb: do early cow when page pinned on src mm
mm: use is_cow_mapping() across tree where proper
...
I read the commit log of the following two:
- bc083a64b6c0 ("init/Kconfig: make COMPILE_TEST depend on !UML")
- 334ef6ed06fa ("init/Kconfig: make COMPILE_TEST depend on !S390")
Both are talking about HAS_IOMEM dependency missing in many drivers.
So, 'depends on HAS_IOMEM' seems the direct, sensible solution to me.
This does not change the behavior of UML. UML still cannot enable
COMPILE_TEST because it does not provide HAS_IOMEM.
The current dependency for S390 is too strong. Under the condition of
CONFIG_PCI=y, S390 provides HAS_IOMEM, hence can enable COMPILE_TEST.
I also removed the meaningless 'default n'.
Link: https://lkml.kernel.org/r/20210224140809.1067582-1-masahiroy@kernel.org
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KP Singh <kpsingh@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Quentin Perret <qperret@google.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus reported a build error due to the GCC plugin incompatibility
when the compiler is upgraded. [1]
GCC plugins are tied to a particular GCC version. So, they must be
rebuilt when the compiler is upgraded.
This seems to be a long-standing flaw since the initial support of
GCC plugins.
Extend commit 8b59cd81dc5e ("kbuild: ensure full rebuild when the
compiler is updated"), so that GCC plugins are covered by the
compiler upgrade detection.
[1]: https://lore.kernel.org/lkml/CAHk-=wieoN5ttOy7SnsGwZv+Fni3R6m-Ut=oxih6bbZ28G+4dw@mail.gmail.com/
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-03-09
The following pull-request contains BPF updates for your *net-next* tree.
We've added 90 non-merge commits during the last 17 day(s) which contain
a total of 114 files changed, 5158 insertions(+), 1288 deletions(-).
The main changes are:
1) Faster bpf_redirect_map(), from Björn.
2) skmsg cleanup, from Cong.
3) Support for floating point types in BTF, from Ilya.
4) Documentation for sys_bpf commands, from Joe.
5) Support for sk_lookup in bpf_prog_test_run, form Lorenz.
6) Enable task local storage for tracing programs, from Song.
7) bpf_for_each_map_elem() helper, from Yonghong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit fbe078d397b4 ("kbuild: lto: add a default list of used symbols")
does not work as expected if the .config file has already specified
CONFIG_UNUSED_KSYMS_WHITELIST="my/own/white/list" before enabling
CONFIG_LTO_CLANG.
So, the user-supplied whitelist and LTO-specific white list must be
independent of each other.
I refactored the shell script so CONFIG_MODVERSIONS and CONFIG_CLANG_LTO
handle whitelists in the same way.
Fixes: fbe078d397b4 ("kbuild: lto: add a default list of used symbols")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
As suggested by John, clean up sockmap related Kconfigs:
Reduce the scope of CONFIG_BPF_STREAM_PARSER down to TCP stream
parser, to reflect its name.
Make the rest sockmap code simply depend on CONFIG_BPF_SYSCALL
and CONFIG_INET, the latter is still needed at this point because
of TCP/UDP proto update. And leave CONFIG_NET_SOCK_MSG untouched,
as it is used by non-sockmap cases.
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Lorenz Bauer <lmb@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-2-xiyou.wangcong@gmail.com
I have a handful of new RISC-V related patches for this merge window:
* A check to ensure drivers are properly using uaccess. This isn't
manifesting with any of the drivers I'm currently using, but may catch
errors in new drivers.
* Some preliminary support for the FU740, along with the HiFive
Unleashed it will appear on.
* NUMA support for RISC-V, which involves making the arm64 code generic.
* Support for kasan on the vmalloc region.
* A handful of new drivers for the Kendryte K210, along with the DT
plumbing required to boot on a handful of K210-based boards.
* Support for allocating ASIDs.
* Preliminary support for kernels larger than 128MiB.
* Various other improvements to our KASAN support, including the
utilization of huge pages when allocating the KASAN regions.
We may have already found a bug with the KASAN_VMALLOC code, but it's
passing my tests. There's a fix in the works, but that will probably
miss the merge window.
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Merge tag 'riscv-for-linus-5.12-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Palmer Dabbelt:
"A handful of new RISC-V related patches for this merge window:
- A check to ensure drivers are properly using uaccess. This isn't
manifesting with any of the drivers I'm currently using, but may
catch errors in new drivers.
- Some preliminary support for the FU740, along with the HiFive
Unleashed it will appear on.
- NUMA support for RISC-V, which involves making the arm64 code
generic.
- Support for kasan on the vmalloc region.
- A handful of new drivers for the Kendryte K210, along with the DT
plumbing required to boot on a handful of K210-based boards.
- Support for allocating ASIDs.
- Preliminary support for kernels larger than 128MiB.
- Various other improvements to our KASAN support, including the
utilization of huge pages when allocating the KASAN regions.
We may have already found a bug with the KASAN_VMALLOC code, but it's
passing my tests. There's a fix in the works, but that will probably
miss the merge window.
* tag 'riscv-for-linus-5.12-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (75 commits)
riscv: Improve kasan population by using hugepages when possible
riscv: Improve kasan population function
riscv: Use KASAN_SHADOW_INIT define for kasan memory initialization
riscv: Improve kasan definitions
riscv: Get rid of MAX_EARLY_MAPPING_SIZE
soc: canaan: Sort the Makefile alphabetically
riscv: Disable KSAN_SANITIZE for vDSO
riscv: Remove unnecessary declaration
riscv: Add Canaan Kendryte K210 SD card defconfig
riscv: Update Canaan Kendryte K210 defconfig
riscv: Add Kendryte KD233 board device tree
riscv: Add SiPeed MAIXDUINO board device tree
riscv: Add SiPeed MAIX GO board device tree
riscv: Add SiPeed MAIX DOCK board device tree
riscv: Add SiPeed MAIX BiT board device tree
riscv: Update Canaan Kendryte K210 device tree
dt-bindings: add resets property to dw-apb-timer
dt-bindings: fix sifive gpio properties
dt-bindings: update sifive uart compatible string
dt-bindings: update sifive clint compatible string
...
On systems with large amounts of reserved memory we may fail to
successfully complete unpack_to_rootfs() and be left with:
Kernel panic - not syncing: write error
this is not too helpful to understand what happened, so let's wrap the
panic() calls with a surrounding show_mem() such that we have a chance of
understanding the memory conditions leading to these allocation failures.
[akpm@linux-foundation.org: replace macro with C function]
Link: https://lkml.kernel.org/r/20210114231517.1854379-1-f.fainelli@gmail.com
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: Barret Rhoden <brho@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently breakpoints in kernel .init.text section are not handled
correctly while allowing to remove them even after corresponding pages
have been freed.
Fix it via killing .init.text section breakpoints just prior to initmem
pages being freed.
Doug: "HW breakpoints aren't handled by this patch but it's probably
not such a big deal".
Link: https://lkml.kernel.org/r/20210224081652.587785-1-sumit.garg@linaro.org
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Suggested-by: Doug Anderson <dianders@chromium.org>
Acked-by: Doug Anderson <dianders@chromium.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This code hunk creates a Version_<LINUX_VERSION_CODE> symbol if
CONFIG_KALLSYMS is disabled. For example, building the kernel v5.10 for
allnoconfig creates the following symbol:
$ nm vmlinux | grep Version_
c116b028 B Version_330240
There is no in-tree user of this symbol.
Commit 197dcffc8ba0 ("init/version.c: define version_string only if
CONFIG_KALLSYMS is not defined") mentions that Version_* is only used
with ksymoops.
However, a commit in the pre-git era [1] had added the statement,
"ksymoops is useless on 2.6. Please use the Oops in its original format".
That statement existed until commit 4eb9241127a0 ("Documentation:
admin-guide: update bug-hunting.rst") finally removed the stale
ksymoops information.
This symbol is no longer needed.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=ad68b2f085f5c79e4759ca2d13947b3c885ee831
Link: https://lkml.kernel.org/r/20210120033452.2895170-1-masahiroy@kernel.org
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Daniel Guilak <guilak@linux.vnet.ibm.com>
Cc: Lee Revell <rlrevell@joe-job.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a kernel parameter stack_depot_disable to disable stack depot. So
that stack hash table doesn't consume any memory when stack depot is
disabled.
The use case is CONFIG_PAGE_OWNER without page_owner=on. Without this
patch, stackdepot will consume the memory for the hashtable. By default,
it's 8M which is never trivial.
With this option, in CONFIG_PAGE_OWNER configured system, page_owner=off,
stack_depot_disable in kernel command line, we could save the wasted
memory for the hashtable.
[akpm@linux-foundation.org: fix CONFIG_STACKDEPOT=n build]
Link: https://lkml.kernel.org/r/1611749198-24316-2-git-send-email-vjitta@codeaurora.org
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Yogesh Lal <ylal@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "KFENCE: A low-overhead sampling-based memory safety error detector", v7.
This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a
low-overhead sampling-based memory safety error detector of heap
use-after-free, invalid-free, and out-of-bounds access errors. This
series enables KFENCE for the x86 and arm64 architectures, and adds
KFENCE hooks to the SLAB and SLUB allocators.
KFENCE is designed to be enabled in production kernels, and has near
zero performance overhead. Compared to KASAN, KFENCE trades performance
for precision. The main motivation behind KFENCE's design, is that with
enough total uptime KFENCE will detect bugs in code paths not typically
exercised by non-production test workloads. One way to quickly achieve a
large enough total uptime is when the tool is deployed across a large
fleet of machines.
KFENCE objects each reside on a dedicated page, at either the left or
right page boundaries. The pages to the left and right of the object
page are "guard pages", whose attributes are changed to a protected
state, and cause page faults on any attempted access to them. Such page
faults are then intercepted by KFENCE, which handles the fault
gracefully by reporting a memory access error.
Guarded allocations are set up based on a sample interval (can be set
via kfence.sample_interval). After expiration of the sample interval,
the next allocation through the main allocator (SLAB or SLUB) returns a
guarded allocation from the KFENCE object pool. At this point, the timer
is reset, and the next allocation is set up after the expiration of the
interval.
To enable/disable a KFENCE allocation through the main allocator's
fast-path without overhead, KFENCE relies on static branches via the
static keys infrastructure. The static branch is toggled to redirect the
allocation to KFENCE.
The KFENCE memory pool is of fixed size, and if the pool is exhausted no
further KFENCE allocations occur. The default config is conservative
with only 255 objects, resulting in a pool size of 2 MiB (with 4 KiB
pages).
We have verified by running synthetic benchmarks (sysbench I/O,
hackbench) and production server-workload benchmarks that a kernel with
KFENCE (using sample intervals 100-500ms) is performance-neutral
compared to a non-KFENCE baseline kernel.
KFENCE is inspired by GWP-ASan [1], a userspace tool with similar
properties. The name "KFENCE" is a homage to the Electric Fence Malloc
Debugger [2].
For more details, see Documentation/dev-tools/kfence.rst added in the
series -- also viewable here:
https://raw.githubusercontent.com/google/kasan/kfence/Documentation/dev-tools/kfence.rst
[1] http://llvm.org/docs/GwpAsan.html
[2] https://linux.die.net/man/3/efence
This patch (of 9):
This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a
low-overhead sampling-based memory safety error detector of heap
use-after-free, invalid-free, and out-of-bounds access errors.
KFENCE is designed to be enabled in production kernels, and has near
zero performance overhead. Compared to KASAN, KFENCE trades performance
for precision. The main motivation behind KFENCE's design, is that with
enough total uptime KFENCE will detect bugs in code paths not typically
exercised by non-production test workloads. One way to quickly achieve a
large enough total uptime is when the tool is deployed across a large
fleet of machines.
KFENCE objects each reside on a dedicated page, at either the left or
right page boundaries. The pages to the left and right of the object
page are "guard pages", whose attributes are changed to a protected
state, and cause page faults on any attempted access to them. Such page
faults are then intercepted by KFENCE, which handles the fault
gracefully by reporting a memory access error. To detect out-of-bounds
writes to memory within the object's page itself, KFENCE also uses
pattern-based redzones. The following figure illustrates the page
layout:
---+-----------+-----------+-----------+-----------+-----------+---
| xxxxxxxxx | O : | xxxxxxxxx | : O | xxxxxxxxx |
| xxxxxxxxx | B : | xxxxxxxxx | : B | xxxxxxxxx |
| x GUARD x | J : RED- | x GUARD x | RED- : J | x GUARD x |
| xxxxxxxxx | E : ZONE | xxxxxxxxx | ZONE : E | xxxxxxxxx |
| xxxxxxxxx | C : | xxxxxxxxx | : C | xxxxxxxxx |
| xxxxxxxxx | T : | xxxxxxxxx | : T | xxxxxxxxx |
---+-----------+-----------+-----------+-----------+-----------+---
Guarded allocations are set up based on a sample interval (can be set
via kfence.sample_interval). After expiration of the sample interval, a
guarded allocation from the KFENCE object pool is returned to the main
allocator (SLAB or SLUB). At this point, the timer is reset, and the
next allocation is set up after the expiration of the interval.
To enable/disable a KFENCE allocation through the main allocator's
fast-path without overhead, KFENCE relies on static branches via the
static keys infrastructure. The static branch is toggled to redirect the
allocation to KFENCE. To date, we have verified by running synthetic
benchmarks (sysbench I/O, hackbench) that a kernel compiled with KFENCE
is performance-neutral compared to the non-KFENCE baseline.
For more details, see Documentation/dev-tools/kfence.rst (added later in
the series).
[elver@google.com: fix parameter description for kfence_object_start()]
Link: https://lkml.kernel.org/r/20201106092149.GA2851373@elver.google.com
[elver@google.com: avoid stalling work queue task without allocations]
Link: https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com
Link: https://lkml.kernel.org/r/20201110135320.3309507-1-elver@google.com
[elver@google.com: fix potential deadlock due to wake_up()]
Link: https://lkml.kernel.org/r/000000000000c0645805b7f982e4@google.com
Link: https://lkml.kernel.org/r/20210104130749.1768991-1-elver@google.com
[elver@google.com: add option to use KFENCE without static keys]
Link: https://lkml.kernel.org/r/20210111091544.3287013-1-elver@google.com
[elver@google.com: add missing copyright and description headers]
Link: https://lkml.kernel.org/r/20210118092159.145934-1-elver@google.com
Link: https://lkml.kernel.org/r/20201103175841.3495947-2-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: SeongJae Park <sjpark@amazon.de>
Co-developed-by: Marco Elver <elver@google.com>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Joern Engel <joern@purestorage.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Fix false-positive build warnings for ARCH=ia64 builds
- Optimize dictionary size for module compression with xz
- Check the compiler and linker versions in Kconfig
- Fix misuse of extra-y
- Support DWARF v5 debug info
- Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
exceeded the limit
- Add generic syscall{tbl,hdr}.sh for cleanups across arches
- Minor cleanups of genksyms
- Minor cleanups of Kconfig
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Merge tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Fix false-positive build warnings for ARCH=ia64 builds
- Optimize dictionary size for module compression with xz
- Check the compiler and linker versions in Kconfig
- Fix misuse of extra-y
- Support DWARF v5 debug info
- Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
exceeded the limit
- Add generic syscall{tbl,hdr}.sh for cleanups across arches
- Minor cleanups of genksyms
- Minor cleanups of Kconfig
* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
kbuild: remove deprecated 'always' and 'hostprogs-y/m'
kbuild: parse C= and M= before changing the working directory
kbuild: reuse this-makefile to define abs_srctree
kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
kconfig: omit --oldaskconfig option for 'make config'
kconfig: fix 'invalid option' for help option
kconfig: remove dead code in conf_askvalue()
kconfig: clean up nested if-conditionals in check_conf()
kconfig: Remove duplicate call to sym_get_string_value()
Makefile: Remove # characters from compiler string
Makefile: reuse CC_VERSION_TEXT
kbuild: check the minimum linker version in Kconfig
kbuild: remove ld-version macro
scripts: add generic syscallhdr.sh
scripts: add generic syscalltbl.sh
arch: syscalls: remove $(srctree)/ prefix from syscall tables
arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
gen_compile_commands: prune some directories
kbuild: simplify access to the kernel's version
...
Merge misc updates from Andrew Morton:
"A few small subsystems and some of MM.
172 patches.
Subsystems affected by this patch series: hexagon, scripts, ntfs,
ocfs2, vfs, and mm (slab-generic, slab, slub, debug, pagecache, swap,
memcg, pagemap, mprotect, mremap, page-reporting, vmalloc, kasan,
pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
mempolicy, oom-kill, hugetlbfs, and migration)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (172 commits)
mm/migrate: remove unneeded semicolons
hugetlbfs: remove unneeded return value of hugetlb_vmtruncate()
hugetlbfs: fix some comment typos
hugetlbfs: correct some obsolete comments about inode i_mutex
hugetlbfs: make hugepage size conversion more readable
hugetlbfs: remove meaningless variable avoid_reserve
hugetlbfs: correct obsolete function name in hugetlbfs_read_iter()
hugetlbfs: use helper macro default_hstate in init_hugetlbfs_fs
hugetlbfs: remove useless BUG_ON(!inode) in hugetlbfs_setattr()
hugetlbfs: remove special hugetlbfs_set_page_dirty()
mm/hugetlb: change hugetlb_reserve_pages() to type bool
mm, oom: fix a comment in dump_task()
mm/mempolicy: use helper range_in_vma() in queue_pages_test_walk()
numa balancing: migrate on fault among multiple bound nodes
mm, compaction: make fast_isolate_freepages() stay within zone
mm/compaction: fix misbehaviors of fast_find_migrateblock()
mm/compaction: correct deferral logic for proactive compaction
mm/compaction: remove duplicated VM_BUG_ON_PAGE !PageLocked
mm/compaction: remove rcu_read_lock during page compaction
z3fold: simplify the zhdr initialization code in init_z3fold_page()
...
The boot param and config determine the value of memcg_sysfs_enabled,
which is unused since commit 10befea91b61 ("mm: memcg/slab: use a single
set of kmem_caches for all allocations") as there are no per-memcg kmem
caches anymore.
Link: https://lkml.kernel.org/r/20210127124745.7928-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Drop support for depercated platforms using SFI, drop the entire
support for SFI that has been long deprecated too and make some
janitorial changes on top of that (Andy Shevchenko).
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Merge tag 'sfi-removal-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull Simple Firmware Interface (SFI) support removal from Rafael Wysocki:
"Drop support for depercated platforms using SFI, drop the entire
support for SFI that has been long deprecated too and make some
janitorial changes on top of that (Andy Shevchenko)"
* tag 'sfi-removal-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
x86/platform/intel-mid: Update Copyright year and drop file names
x86/platform/intel-mid: Remove unused header inclusion in intel-mid.h
x86/platform/intel-mid: Drop unused __intel_mid_cpu_chip and Co.
x86/platform/intel-mid: Get rid of intel_scu_ipc_legacy.h
x86/PCI: Describe @reg for type1_access_ok()
x86/PCI: Get rid of custom x86 model comparison
sfi: Remove framework for deprecated firmware
cpufreq: sfi-cpufreq: Remove driver for deprecated firmware
media: atomisp: Remove unused header
mfd: intel_msic: Remove driver for deprecated platform
x86/apb_timer: Remove driver for deprecated platform
x86/platform/intel-mid: Remove unused leftovers (vRTC)
x86/platform/intel-mid: Remove unused leftovers (msic)
x86/platform/intel-mid: Remove unused leftovers (msic_thermal)
x86/platform/intel-mid: Remove unused leftovers (msic_power_btn)
x86/platform/intel-mid: Remove unused leftovers (msic_gpio)
x86/platform/intel-mid: Remove unused leftovers (msic_battery)
x86/platform/intel-mid: Remove unused leftovers (msic_ocd)
x86/platform/intel-mid: Remove unused leftovers (msic_audio)
platform/x86: intel_scu_wdt: Drop mistakenly added const
In commit 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") I
disabled this option because it's hugely expensive at build time, and I
questioned how much use it gets.
Several people piped up and convinced me it's actually useful, so
instead of disabling it entirely, it now depends on EXPERT and gets
disabled by COMPILE_TEST builds so that 'allmodconfig' style things
don't enable it.
I still hope somebody will take a look at the build time issue, because
as Arnd also noted:
"However, the combination of thinlto and trim indeed has a steep cost
in compile time, taking almost twice as long as a normal defconfig
(gc-sections makes it slightly faster)"
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Cristoph Hellwig <hch@lst.de>,
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The removal of EXPORT_UNUSED_SYMBOL() in commit 367948220fce looks like
(and was sold as) a no-op, but it actually had a rather serious and
subtle side effect: the UNUSED_SYMBOLS option not only enabled the
removed (unused) functionality, it also _disabled_ the TRIM_UNUSED_KSYMS
functionality.
And it turns out that TRIM_UNUSED_KSYMS is a huge time waste, and takes
up a third of the kernel build time for me. For no actual upside, since
no distro is likely to ever be able to enable it (because they all
support external kernel modules).
Rather than re-enable EXPORT_UNUSED_SYMBOL, this just disables the
TRIM_UNUSED_KSYMS option by marking it broken. I'm tempted to just
remove the support entirely, but maybe somebody has a use-case and can
fix the behavior of it.
I could have just disabled it for COMPILE_TEST, but it really smells
like the TRIM_UNUSED_KSYMS option is badly done and not really useful,
so this takes the more direct approach - let's see if anybody ever
actually notices or complains.
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jessica Yu <jeyu@kernel.org>
Fixes: 367948220fce ("module: remove EXPORT_UNUSED_SYMBOL*")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Summary of modules changes for the 5.12 merge window:
- Retire EXPORT_UNUSED_SYMBOL() and EXPORT_SYMBOL_GPL_FUTURE(). These export
types were introduced between 2006 - 2008. All the of the unused symbols have
been long removed and gpl future symbols were converted to gpl quite a long
time ago, and I don't believe these export types have been used ever since.
So, I think it should be safe to retire those export types now. (Christoph Hellwig)
- Refactor and clean up some aged code cruft in the module loader (Christoph Hellwig)
- Build {,module_}kallsyms_on_each_symbol only when livepatching is enabled, as
it is the only caller (Christoph Hellwig)
- Unexport find_module() and module_mutex and fix the last module
callers to not rely on these anymore. Make module_mutex internal to
the module loader. (Christoph Hellwig)
- Harden ELF checks on module load and validate ELF structures before checking
the module signature (Frank van der Linden)
- Fix undefined symbol warning for clang (Fangrui Song)
- Fix smatch warning (Dan Carpenter)
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull module updates from Jessica Yu:
- Retire EXPORT_UNUSED_SYMBOL() and EXPORT_SYMBOL_GPL_FUTURE(). These
export types were introduced between 2006 - 2008. All the of the
unused symbols have been long removed and gpl future symbols were
converted to gpl quite a long time ago, and I don't believe these
export types have been used ever since. So, I think it should be safe
to retire those export types now (Christoph Hellwig)
- Refactor and clean up some aged code cruft in the module loader
(Christoph Hellwig)
- Build {,module_}kallsyms_on_each_symbol only when livepatching is
enabled, as it is the only caller (Christoph Hellwig)
- Unexport find_module() and module_mutex and fix the last module
callers to not rely on these anymore. Make module_mutex internal to
the module loader (Christoph Hellwig)
- Harden ELF checks on module load and validate ELF structures before
checking the module signature (Frank van der Linden)
- Fix undefined symbol warning for clang (Fangrui Song)
- Fix smatch warning (Dan Carpenter)
* tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: potential uninitialized return in module_kallsyms_on_each_symbol()
module: remove EXPORT_UNUSED_SYMBOL*
module: remove EXPORT_SYMBOL_GPL_FUTURE
module: move struct symsearch to module.c
module: pass struct find_symbol_args to find_symbol
module: merge each_symbol_section into find_symbol
module: remove each_symbol_in_section
module: mark module_mutex static
kallsyms: only build {,module_}kallsyms_on_each_symbol when required
kallsyms: refactor {,module_}kallsyms_on_each_symbol
module: use RCU to synchronize find_module
module: unexport find_module and module_mutex
drm: remove drm_fb_helper_modinit
powerpc/powernv: remove get_cxl_module
module: harden ELF info handling
module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols
- Clang LTO build infrastructure and arm64-specific enablement (Sami Tolvanen)
- Recursive build CC_FLAGS_LTO fix (Alexander Lobakin)
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Merge tag 'clang-lto-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull clang LTO updates from Kees Cook:
"Clang Link Time Optimization.
This is built on the work done preparing for LTO by arm64 folks,
tracing folks, etc. This includes the core changes as well as the
remaining pieces for arm64 (LTO has been the default build method on
Android for about 3 years now, as it is the prerequisite for the
Control Flow Integrity protections).
While x86 LTO enablement is done, it depends on some pending objtool
clean-ups. It's possible that I'll send a "part 2" pull request for
LTO that includes x86 support.
For merge log posterity, and as detailed in commit dc5723b02e52
("kbuild: add support for Clang LTO"), here is the lt;dr to do an LTO
build:
make LLVM=1 LLVM_IAS=1 defconfig
scripts/config -e LTO_CLANG_THIN
make LLVM=1 LLVM_IAS=1
(To do a cross-compile of arm64, add "CROSS_COMPILE=aarch64-linux-gnu-"
and "ARCH=arm64" to the "make" command lines.)
Summary:
- Clang LTO build infrastructure and arm64-specific enablement (Sami
Tolvanen)
- Recursive build CC_FLAGS_LTO fix (Alexander Lobakin)"
* tag 'clang-lto-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
kbuild: prevent CC_FLAGS_LTO self-bloating on recursive rebuilds
arm64: allow LTO to be selected
arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS
arm64: vdso: disable LTO
drivers/misc/lkdtm: disable LTO for rodata.o
efi/libstub: disable LTO
scripts/mod: disable LTO for empty.c
modpost: lto: strip .lto from module names
PCI: Fix PREL32 relocations for LTO
init: lto: fix PREL32 relocations
init: lto: ensure initcall ordering
kbuild: lto: add a default list of used symbols
kbuild: lto: merge module sections
kbuild: lto: limit inlining
kbuild: lto: fix module versioning
kbuild: add support for Clang LTO
tracing: move function tracer options to Kconfig
drm userspaces uses this, systemd uses this, makes sense to pull it
out from the checkpoint-restore bundle. Kees reviewed this from
security pov and is happy with the final version.
LWN coverage: https://lwn.net/Articles/845448/
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Merge tag 'topic/kcmp-kconfig-2021-02-22' of git://anongit.freedesktop.org/drm/drm
Pull kcmp kconfig update from Daniel Vetter:
"Make the kcmp syscall available independently of checkpoint/restore.
drm userspaces uses this, systemd uses this, so makes sense to pull it
out from the checkpoint-restore bundle.
Kees reviewed this from security pov and is happy with the final
version"
Link: https://lwn.net/Articles/845448/
* tag 'topic/kcmp-kconfig-2021-02-22' of git://anongit.freedesktop.org/drm/drm:
kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE
Unify the two scripts/ld-version.sh and scripts/lld-version.sh, and
check the minimum linker version like scripts/cc-version.sh did.
I tested this script for some corner cases reported in the past:
- GNU ld version 2.25-15.fc23
as reported by commit 8083013fc320 ("ld-version: Fix it on Fedora")
- GNU ld (GNU Binutils) 2.20.1.20100303
as reported by commit 0d61ed17dd30 ("ld-version: Drop the 4th and
5th version components")
This script show an error message if the linker is too old:
$ make LD=ld.lld-9
SYNC include/config/auto.conf
***
*** Linker is too old.
*** Your LLD version: 9.0.1
*** Minimum LLD version: 10.0.1
***
scripts/Kconfig.include:50: Sorry, this linker is not supported.
make[2]: *** [scripts/kconfig/Makefile:71: syncconfig] Error 1
make[1]: *** [Makefile:600: syncconfig] Error 2
make: *** [Makefile:708: include/config/auto.conf] Error 2
I also moved the check for gold to this script, so gold is still rejected:
$ make LD=gold
SYNC include/config/auto.conf
gold linker is not supported as it is not capable of linking the kernel proper.
scripts/Kconfig.include:50: Sorry, this linker is not supported.
make[2]: *** [scripts/kconfig/Makefile:71: syncconfig] Error 1
make[1]: *** [Makefile:600: syncconfig] Error 2
make: *** [Makefile:708: include/config/auto.conf] Error 2
Thanks to David Laight for suggesting shell script improvements.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
[ NOTE: unfortunately this tree had to be freshly rebased today,
it's a same-content tree of 82891be90f3c (-next published)
merged with v5.11.
The main reason for the rebase was an authorship misattribution
problem with a new commit, which we noticed in the last minute,
and which we didn't want to be merged upstream. The offending
commit was deep in the tree, and dependent commits had to be
rebased as well. ]
- Core scheduler updates:
- Add CONFIG_PREEMPT_DYNAMIC: this in its current form adds the
preempt=none/voluntary/full boot options (default: full),
to allow distros to build a PREEMPT kernel but fall back to
close to PREEMPT_VOLUNTARY (or PREEMPT_NONE) runtime scheduling
behavior via a boot time selection.
There's also the /debug/sched_debug switch to do this runtime.
This feature is implemented via runtime patching (a new variant of static calls).
The scope of the runtime patching can be best reviewed by looking
at the sched_dynamic_update() function in kernel/sched/core.c.
( Note that the dynamic none/voluntary mode isn't 100% identical,
for example preempt-RCU is available in all cases, plus the
preempt count is maintained in all models, which has runtime
overhead even with the code patching. )
The PREEMPT_VOLUNTARY/PREEMPT_NONE models, used by the vast majority
of distributions, are supposed to be unaffected.
- Fix ignored rescheduling after rcu_eqs_enter(). This is a bug that
was found via rcutorture triggering a hang. The bug is that
rcu_idle_enter() may wake up a NOCB kthread, but this happens after
the last generic need_resched() check. Some cpuidle drivers fix it
by chance but many others don't.
In true 2020 fashion the original bug fix has grown into a 5-patch
scheduler/RCU fix series plus another 16 RCU patches to address
the underlying issue of missed preemption events. These are the
initial fixes that should fix current incarnations of the bug.
- Clean up rbtree usage in the scheduler, by providing & using the following
consistent set of rbtree APIs:
partial-order; less() based:
- rb_add(): add a new entry to the rbtree
- rb_add_cached(): like rb_add(), but for a rb_root_cached
total-order; cmp() based:
- rb_find(): find an entry in an rbtree
- rb_find_add(): find an entry, and add if not found
- rb_find_first(): find the first (leftmost) matching entry
- rb_next_match(): continue from rb_find_first()
- rb_for_each(): iterate a sub-tree using the previous two
- Improve the SMP/NUMA load-balancer: scan for an idle sibling in a single pass.
This is a 4-commit series where each commit improves one aspect of the idle
sibling scan logic.
- Improve the cpufreq cooling driver by getting the effective CPU utilization
metrics from the scheduler
- Improve the fair scheduler's active load-balancing logic by reducing the number
of active LB attempts & lengthen the load-balancing interval. This improves
stress-ng mmapfork performance.
- Fix CFS's estimated utilization (util_est) calculation bug that can result in
too high utilization values
- Misc updates & fixes:
- Fix the HRTICK reprogramming & optimization feature
- Fix SCHED_SOFTIRQ raising race & warning in the CPU offlining code
- Reduce dl_add_task_root_domain() overhead
- Fix uprobes refcount bug
- Process pending softirqs in flush_smp_call_function_from_idle()
- Clean up task priority related defines, remove *USER_*PRIO and
USER_PRIO()
- Simplify the sched_init_numa() deduplication sort
- Documentation updates
- Fix EAS bug in update_misfit_status(), which degraded the quality
of energy-balancing
- Smaller cleanups
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Core scheduler updates:
- Add CONFIG_PREEMPT_DYNAMIC: this in its current form adds the
preempt=none/voluntary/full boot options (default: full), to allow
distros to build a PREEMPT kernel but fall back to close to
PREEMPT_VOLUNTARY (or PREEMPT_NONE) runtime scheduling behavior via
a boot time selection.
There's also the /debug/sched_debug switch to do this runtime.
This feature is implemented via runtime patching (a new variant of
static calls).
The scope of the runtime patching can be best reviewed by looking
at the sched_dynamic_update() function in kernel/sched/core.c.
( Note that the dynamic none/voluntary mode isn't 100% identical,
for example preempt-RCU is available in all cases, plus the
preempt count is maintained in all models, which has runtime
overhead even with the code patching. )
The PREEMPT_VOLUNTARY/PREEMPT_NONE models, used by the vast
majority of distributions, are supposed to be unaffected.
- Fix ignored rescheduling after rcu_eqs_enter(). This is a bug that
was found via rcutorture triggering a hang. The bug is that
rcu_idle_enter() may wake up a NOCB kthread, but this happens after
the last generic need_resched() check. Some cpuidle drivers fix it
by chance but many others don't.
In true 2020 fashion the original bug fix has grown into a 5-patch
scheduler/RCU fix series plus another 16 RCU patches to address the
underlying issue of missed preemption events. These are the initial
fixes that should fix current incarnations of the bug.
- Clean up rbtree usage in the scheduler, by providing & using the
following consistent set of rbtree APIs:
partial-order; less() based:
- rb_add(): add a new entry to the rbtree
- rb_add_cached(): like rb_add(), but for a rb_root_cached
total-order; cmp() based:
- rb_find(): find an entry in an rbtree
- rb_find_add(): find an entry, and add if not found
- rb_find_first(): find the first (leftmost) matching entry
- rb_next_match(): continue from rb_find_first()
- rb_for_each(): iterate a sub-tree using the previous two
- Improve the SMP/NUMA load-balancer: scan for an idle sibling in a
single pass. This is a 4-commit series where each commit improves
one aspect of the idle sibling scan logic.
- Improve the cpufreq cooling driver by getting the effective CPU
utilization metrics from the scheduler
- Improve the fair scheduler's active load-balancing logic by
reducing the number of active LB attempts & lengthen the
load-balancing interval. This improves stress-ng mmapfork
performance.
- Fix CFS's estimated utilization (util_est) calculation bug that can
result in too high utilization values
Misc updates & fixes:
- Fix the HRTICK reprogramming & optimization feature
- Fix SCHED_SOFTIRQ raising race & warning in the CPU offlining code
- Reduce dl_add_task_root_domain() overhead
- Fix uprobes refcount bug
- Process pending softirqs in flush_smp_call_function_from_idle()
- Clean up task priority related defines, remove *USER_*PRIO and
USER_PRIO()
- Simplify the sched_init_numa() deduplication sort
- Documentation updates
- Fix EAS bug in update_misfit_status(), which degraded the quality
of energy-balancing
- Smaller cleanups"
* tag 'sched-core-2021-02-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
sched,x86: Allow !PREEMPT_DYNAMIC
entry/kvm: Explicitly flush pending rcuog wakeup before last rescheduling point
entry: Explicitly flush pending rcuog wakeup before last rescheduling point
rcu/nocb: Trigger self-IPI on late deferred wake up before user resume
rcu/nocb: Perform deferred wake up before last idle's need_resched() check
rcu: Pull deferred rcuog wake up to rcu_eqs_enter() callers
sched/features: Distinguish between NORMAL and DEADLINE hrtick
sched/features: Fix hrtick reprogramming
sched/deadline: Reduce rq lock contention in dl_add_task_root_domain()
uprobes: (Re)add missing get_uprobe() in __find_uprobe()
smp: Process pending softirqs in flush_smp_call_function_from_idle()
sched: Harden PREEMPT_DYNAMIC
static_call: Allow module use without exposing static_call_key
sched: Add /debug/sched_preempt
preempt/dynamic: Support dynamic preempt with preempt= boot option
preempt/dynamic: Provide irqentry_exit_cond_resched() static call
preempt/dynamic: Provide preempt_schedule[_notrace]() static calls
preempt/dynamic: Provide cond_resched() and might_resched() static calls
preempt: Introduce CONFIG_PREEMPT_DYNAMIC
static_call: Provide DEFINE_STATIC_CALL_RET0()
...
The "oprofile" user-space tools don't use the kernel OPROFILE support any more,
and haven't in a long time. User-space has been converted to the perf
interfaces.
The dcookies stuff is only used by the oprofile code. Now that oprofile's
support is getting removed from the kernel, there is no need for dcookies as
well.
Remove kernel's old oprofile and dcookies support.
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Merge tag 'oprofile-removal-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux
Pull oprofile and dcookies removal from Viresh Kumar:
"Remove oprofile and dcookies support
The 'oprofile' user-space tools don't use the kernel OPROFILE support
any more, and haven't in a long time. User-space has been converted to
the perf interfaces.
The dcookies stuff is only used by the oprofile code. Now that
oprofile's support is getting removed from the kernel, there is no
need for dcookies as well.
Remove kernel's old oprofile and dcookies support"
* tag 'oprofile-removal-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/linux:
fs: Remove dcookies support
drivers: Remove CONFIG_OPROFILE support
arch: xtensa: Remove CONFIG_OPROFILE support
arch: x86: Remove CONFIG_OPROFILE support
arch: sparc: Remove CONFIG_OPROFILE support
arch: sh: Remove CONFIG_OPROFILE support
arch: s390: Remove CONFIG_OPROFILE support
arch: powerpc: Remove oprofile
arch: powerpc: Stop building and using oprofile
arch: parisc: Remove CONFIG_OPROFILE support
arch: mips: Remove CONFIG_OPROFILE support
arch: microblaze: Remove CONFIG_OPROFILE support
arch: ia64: Remove rest of perfmon support
arch: ia64: Remove CONFIG_OPROFILE support
arch: hexagon: Don't select HAVE_OPROFILE
arch: arc: Remove CONFIG_OPROFILE support
arch: arm: Remove CONFIG_OPROFILE support
arch: alpha: Remove CONFIG_OPROFILE support
Some architectures(eg, ARM and riscv) have similar logic to
check and reserve the memory of initrd, let's provide a common
function reserve_initrd_mem() to reduce duplicated code.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Userspace has discovered the functionality offered by SYS_kcmp and has
started to depend upon it. In particular, Mesa uses SYS_kcmp for
os_same_file_description() in order to identify when two fd (e.g. device
or dmabuf) point to the same struct file. Since they depend on it for
core functionality, lift SYS_kcmp out of the non-default
CONFIG_CHECKPOINT_RESTORE into the selectable syscall category.
Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to
deduplicate the per-service file descriptor store.
Note that some distributions such as Ubuntu are already enabling
CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp.
References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> # DRM depends on kcmp
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> # systemd uses kcmp
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@chris-wilson.co.uk
Paul Gortmaker reported a regression in the GCC version check. [1]
If you use GCC 4.8, the build breaks before showing the error message
"error Sorry, your version of GCC is too old - please use 4.9 or newer."
I do not want to apply his fix-up since it implies we would not be able
to remove any cc-option test. Anyway, I admit checking the GCC version
in <linux/compiler-gcc.h> is too late.
Almost at the same time, Linus also suggested to move the compiler
version error to Kconfig time. [2]
I unified the two similar scripts, gcc-version.sh and clang-version.sh
into cc-version.sh. The old scripts invoked the compiler multiple times
(3 times for gcc-version.sh, 4 times for clang-version.sh). I refactored
the code so the new one invokes the compiler just once, and also tried
my best to use shell-builtin commands where possible.
The new script runs faster.
$ time ./scripts/clang-version.sh clang
120000
real 0m0.029s
user 0m0.012s
sys 0m0.021s
$ time ./scripts/cc-version.sh clang
Clang 120000
real 0m0.009s
user 0m0.006s
sys 0m0.004s
cc-version.sh also shows an error message if the compiler is too old:
$ make defconfig CC=clang-9
*** Default configuration is based on 'x86_64_defconfig'
***
*** Compiler is too old.
*** Your Clang version: 9.0.1
*** Minimum Clang version: 10.0.1
***
scripts/Kconfig.include:46: Sorry, this compiler is not supported.
make[1]: *** [scripts/kconfig/Makefile:81: defconfig] Error 1
make: *** [Makefile:602: defconfig] Error 2
The new script takes care of ICC because we have <linux/compiler-intel.h>
although I am not sure if building the kernel with ICC is well-supported.
[1]: https://lore.kernel.org/r/20210110190807.134996-1-paul.gortmaker@windriver.com
[2]: https://lore.kernel.org/r/CAHk-=wh-+TMHPTFo1qs-MYyK7tZh-OQovA=pP3=e06aCVp6_kA@mail.gmail.com
Fixes: 87de84c9140e ("kbuild: remove cc-option test of -Werror=date-time")
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
SFI-based platforms are gone. So does this framework.
This removes mention of SFI through the drivers and other code as well.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
EXPORT_UNUSED_SYMBOL* is not actually used anywhere. Remove the
unused functionality as we generally just remove unused code anyway.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
On ARCH=um, loading a module doesn't result in its constructors getting
called, which breaks module gcov since the debugfs files are never
registered. On the other hand, in-kernel constructors have already been
called by the dynamic linker, so we can't call them again.
Get out of this conundrum by allowing CONFIG_CONSTRUCTORS to be
selected, but avoiding the in-kernel constructor calls.
Also remove the "if !UML" from GCOV selecting CONSTRUCTORS now, since we
really do want CONSTRUCTORS, just not kernel binary ones.
Link: https://lkml.kernel.org/r/20210120172041.c246a2cac2fb.I1358f584b76f1898373adfed77f4462c8705b736@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On some archs, the idle task can call into cpu_suspend(). The cpu_suspend()
will disable or pause function graph tracing, as there's some paths in
bringing down the CPU that can have issues with its return address being
modified. The task_struct structure has a "tracing_graph_pause" atomic
counter, that when set to something other than zero, the function graph
tracer will not modify the return address.
The problem is that the tracing_graph_pause counter is initialized when the
function graph tracer is enabled. This can corrupt the counter for the idle
task if it is suspended in these architectures.
CPU 1 CPU 2
----- -----
do_idle()
cpu_suspend()
pause_graph_tracing()
task_struct->tracing_graph_pause++ (0 -> 1)
start_graph_tracing()
for_each_online_cpu(cpu) {
ftrace_graph_init_idle_task(cpu)
task-struct->tracing_graph_pause = 0 (1 -> 0)
unpause_graph_tracing()
task_struct->tracing_graph_pause-- (0 -> -1)
The above should have gone from 1 to zero, and enabled function graph
tracing again. But instead, it is set to -1, which keeps it disabled.
There's no reason that the field tracing_graph_pause on the task_struct can
not be initialized at boot up.
Cc: stable@vger.kernel.org
Fixes: 380c4b1411ccd ("tracing/function-graph-tracer: append the tracing_graph_flag")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211339
Reported-by: pierre.gondois@arm.com
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The "oprofile" user-space tools don't use the kernel OPROFILE support
any more, and haven't in a long time. User-space has been converted to
the perf interfaces.
Remove kernel's old oprofile support.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Robert Richter <rric@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org> #RCU
Acked-by: William Cohen <wcohen@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
We're using arch_scale_thermal_pressure() to retrieve per CPU thermal
pressure.
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20210127054451.1240-1-zbestahu@gmail.com
This reverts commit 757055ae8dedf5333af17b3b5b4b70ba9bc9da4e.
The commit caused that ttynull was used as the default console
on several systems[1][2][3]. As a result, the console was
blank even when a better alternative existed.
It happened when there was no console configured
on the command line and ttynull_init() was the first initcall
calling register_console().
Or it happened when /dev/ did not exist when console_on_rootfs()
was called. It was not able to open /dev/console even though
a console driver was registered. It tried to add ttynull console
but it obviously did not help. But ttynull became the preferred
console and was used by /dev/console when it was available later.
The commit tried to fix a historical problem that have been there
for ages. The primary motivation was the commit 3cffa06aeef7ece30f6
("printk/console: Allow to disable console output by using console=""
or console=null"). It provided a clean solution for a workaround
that was widely used and worked only by chance.
This revert causes that the console="" or console=null command line
options will again work only by chance. These options will cause that
a particular console will be preferred and the default (tty) ones
will not get enabled. There will be no console registered at
all. As a result there won't be stdin, stdout, and stderr for
the init process. But it worked exactly this way even before.
The proper solution has to fulfill many conditions:
+ Register ttynull only when explicitly required or as
the ultimate fallback.
+ ttynull should get associated with /dev/console but it must
not become preferred console when used as a fallback.
Especially, it must still be possible to replace it
by a better console later.
Such a change requires clean up of the register_console() code.
Otherwise, it would be even harder to follow. Especially, the use
of has_preferred_console and CON_CONSDEV flag is tricky. The clean
up is risky. The ordering of consoles is not well defined. And
any changes tend to break existing user settings.
Do the revert at the least risky solution for now.
[1] https://lore.kernel.org/linux-kselftest/20201221144302.GR4077@smile.fi.intel.com/
[2] https://lore.kernel.org/lkml/d2a3b3c0-e548-7dd1-730f-59bc5c04e191@synopsys.com/
[3] https://patchwork.ozlabs.org/project/linux-um/patch/20210105120128.10854-1-thomas@m3y3r.de/
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Vineet Gupta <vgupta@synopsys.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull RCU fix from Paul McKenney:
"This is a fix for a regression in the v5.10 merge window, but it was
reported quite late in the v5.10 process, plus generating and testing
the fix took some time.
The regression is due to commit 36dadef23fcc ("kprobes: Init kprobes
in early_initcall") which on powerpc can use RCU Tasks before
initialization, resulting in boot failures.
The fix is straightforward, simply moving initialization of RCU Tasks
before the early_initcall()s. The fix has been exposed to -next and
kbuild test robot testing, and has been tested by the PowerPC guys"
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
rcu-tasks: Move RCU-tasks initialization to before early_initcall()
Masahiro Yamada
Nayna Jain
Sami Tolvanen
Kees Cook
Vipin Sharma
Kenta.Tada@sony.com
David S. Miller
Cao jin
Linus Torvalds
Cong Wang
Florian Fainelli
Sumit Garg
Bhaskar Chowdhury
Vijayanand Jitta
Alexander Potapenko
Vlastimil Babka
Kefeng Wang
Ingo Molnar
Chris Wilson
Andy Shevchenko
Christoph Hellwig
Johannes Berg
Steven Rostedt (VMware)
Viresh Kumar
Yue Hu
Petr Mladek