2298 Commits

Author SHA1 Message Date
Christoph Hellwig
cd3acb6a79 init: add an init_symlink helper
Add a simple helper to symlink with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_symlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
812931d693 init: add an init_link helper
Add a simple helper to link with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_link.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
eb9d7d390e init: add an init_eaccess helper
Add a simple helper to check if a file exists based on kernel space file
name and switch the early init code over to it.  Note that this
theoretically changes behavior as it always is based on the effective
permissions.  But during early init that doesn't make a difference.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
1097742efc init: add an init_chmod helper
Add a simple helper to chmod with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:53 +02:00
Christoph Hellwig
b873498f99 init: add an init_chown helper
Add a simple helper to chown with a kernel space file name and switch
the early init code over to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
4b7ca5014c init: add an init_chroot helper
Add a simple helper to chroot with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_chroot.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
db63f1e315 init: add an init_chdir helper
Add a simple helper to chdir with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_chdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
20cce026c3 init: add an init_rmdir helper
Add a simple helper to rmdir with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_rmdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
8fb9f73e5a init: add an init_unlink helper
Add a simple helper to unlink with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_unlink.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:52 +02:00
Christoph Hellwig
09267defa3 init: add an init_umount helper
Like ksys_umount, but takes a kernel pointer for the destination path.
Switch over the umount in the init code, which just happen to work due to
the implicit set_fs(KERNEL_DS) during early init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00
Christoph Hellwig
c60166f042 init: add an init_mount helper
Like do_mount, but takes a kernel pointer for the destination path.
Switch over the mounts in the init code and devtmpfs to it, which
just happen to work due to the implicit set_fs(KERNEL_DS) during early
init right now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00
Christoph Hellwig
09cbcec07b init: mark create_dev as __init
This helper is only used for the early init code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00
Christoph Hellwig
a94b521448 init: mark console_on_rootfs as __init
This helper is only used for the early init code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00
Christoph Hellwig
916db733de init: initialize ramdisk_execute_command at compile time
Set ramdisk_execute_command to "/init" at compile time.  The command
line can still override it, but this saves a few instructions and
removes a NULL check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31 08:17:51 +02:00
Christoph Hellwig
38b082236e initramfs: use vfs_utimes in do_copy
Don't bother saving away the pathname and just use the new struct path
based utimes helper instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31 08:16:01 +02:00
Christoph Hellwig
8f740636d9 init: open code setting up stdin/stdout/stderr
Don't rely on the implicit set_fs(KERNEL_DS) for ksys_open to work, but
instead open a struct file for /dev/console and then install it as FD
0/1/2 manually.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31 08:16:00 +02:00
Christoph Hellwig
bf6419e4d5 initramfs: switch initramfs unpacking to struct file based APIs
There is no good reason to mess with file descriptors from in-kernel
code, switch the initramfs unpacking to struct file based write
instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31 08:16:00 +02:00
Christoph Hellwig
b2a74d5f9d initramfs: remove clean_rootfs
There is no point in trying to clean up after unpacking the initramfs
failed, as it should never get past the magic number check.  In addition
the current code only removes file that are direct children of the root
entry, which wasn't complete anyway

Fixes: df52092f3c97 ("fastboot: remove duplicate unpack_to_rootfs()")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-30 08:22:48 +02:00
Christoph Hellwig
9ab6b71849 initramfs: remove the populate_initrd_image and clean_rootfs stubs
If initrd support is not enable just print the warning directly instead
of hiding the fact that we just failed behind two stub functions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30 08:22:47 +02:00
Christoph Hellwig
9acc17baf1 initrd: mark initrd support as deprecated
The classic initial ramdisk has been replaced by the much more
flexible and efficient initramfs a long time.  Warn about it being
removed soon.

Includes a spelling fix from Colin Ian King <colin.king@canonical.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30 08:22:47 +02:00
Christoph Hellwig
f0ea68f139 initrd: mark init_linuxrc as __init
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30 08:22:47 +02:00
Christoph Hellwig
bef1732996 initrd: switch initrd loading to struct file based APIs
There is no good reason to mess with file descriptors from in-kernel
code, switch the initrd loading to struct file based read and writes
instead.

Also Pass an explicit offset instead of ->f_pos, and to make that easier,
use file scope file structs and offsets everywhere except for
identify_ramdisk_image instead of the current strange mix.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30 08:22:47 +02:00
Christoph Hellwig
899ac10cc0 initrd: remove the BLKFLSBUF call in handle_initrd
BLKFLSBUF used to be overloaded for the ramdisk driver to free the whole
ramdisk, which was completely different behavior compared to all other
drivers.  But this magic overload got removed in commit ff26956875c2
("brd: remove support for BLKFLSBUF"), so this call is entirely
pointless now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30 08:22:47 +02:00
Christoph Hellwig
c8376994c8 initrd: remove support for multiple floppies
Remove the special handling for multiple floppies in the initrd code.
No one should be using floppies for booting these days. (famous last
words..)

Includes a spelling fix from Colin Ian King <colin.king@canonical.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30 08:22:33 +02:00
Ahmed S. Darwish
b75058614f sched: tasks: Use sequence counter with associated spinlock
A sequence counter write side critical section must be protected by some
form of locking to serialize writers. A plain seqcount_t does not
contain the information of which lock must be held when entering a write
side critical section.

Use the new seqcount_spinlock_t data type, which allows to associate a
spinlock with the sequence counter. This enables lockdep to verify that
the spinlock used for writer serialization is held when the write side
critical section is entered.

If lockdep is disabled this lock association is compiled out and has
neither storage size nor runtime overhead.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200720155530.1173732-14-a.darwish@linutronix.de
2020-07-29 16:14:26 +02:00
Valentin Schneider
fcd7c9c3c3 arm, arm64: Fix selection of CONFIG_SCHED_THERMAL_PRESSURE
Qian reported that the current setup forgoes the Kconfig dependencies and
results in warnings such as:

  WARNING: unmet direct dependencies detected for SCHED_THERMAL_PRESSURE
    Depends on [n]: SMP [=y] && CPU_FREQ_THERMAL [=n]
    Selected by [y]:
    - ARM64 [=y]

Revert commit

  e17ae7fea871 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE")

and re-implement it by making the option default to 'y' for arm64 and arm,
which respects Kconfig dependencies (i.e. will remain 'n' if
CPU_FREQ_THERMAL=n).

Fixes: e17ae7fea871 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE")
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200729135718.1871-1-valentin.schneider@arm.com
2020-07-29 16:14:16 +02:00
Ingo Molnar
2d65685a4a Merge branch 'x86/urgent' into x86/cleanups
Refresh the branch for a dependent commit.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-26 19:52:30 +02:00
Valentin Schneider
98eb401d09 sched: Cleanup SCHED_THERMAL_PRESSURE kconfig entry
As Russell pointed out [1], this option is severely lacking in the
documentation department, and figuring out if one has the required
dependencies to benefit from turning it on is not straightforward.

Make it non user-visible, and add a bit of help to it. While at it, make it
depend on CPU_FREQ_THERMAL.

[1]: https://lkml.kernel.org/r/20200603173150.GB1551@shell.armlinux.org.uk

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200712165917.9168-3-valentin.schneider@arm.com
2020-07-22 10:22:06 +02:00
Eric W. Biederman
be619f7f06 exec: Implement kernel_execve
To allow the kernel not to play games with set_fs to call exec
implement kernel_execve.  The function kernel_execve takes pointers
into kernel memory and copies the values pointed to onto the new
userspace stack.

The calls with arguments from kernel space of do_execve are replaced
with calls to kernel_execve.

The calls do_execve and do_execveat are made static as there are now
no callers outside of exec.

The comments that mention do_execve are updated to refer to
kernel_execve or execve depending on the circumstances.  In addition
to correcting the comments, this makes it easy to grep for do_execve
and verify it is not used.

Inspired-by: https://lkml.kernel.org/r/20200627072704.2447163-1-hch@lst.de
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/87wo365ikj.fsf@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2020-07-21 08:24:52 -05:00
Christoph Hellwig
4f5b246b37 md: move the early init autodetect code to drivers/md/
Just like the NFS and CIFS root code this better lives with the
driver it is tightly integrated with.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-16 15:34:47 +02:00
Christoph Hellwig
881627f353 init: remove the bstat helper
The only caller of the bstat function becomes cleaner and simpler when
open coding the function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: NeilBrown <neilb@suse.de>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-16 15:34:42 +02:00
Kees Cook
c818c03b66 seccomp: Report number of loaded filters in /proc/$pid/status
A common question asked when debugging seccomp filters is "how many
filters are attached to your process?" Provide a way to easily answer
this question through /proc/$pid/status with a "Seccomp_filters" line.

Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-10 16:01:51 -07:00
Masahiro Yamada
b816b3db15 kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang
scripts/cc-can-link.sh tests if the compiler can link userspace
programs.

When $(CC) is GCC, it is checked against the target architecture
because the toolchain prefix is specified as a part of $(CC).

When $(CC) is Clang, it is checked against the host architecture
because --target option is missing.

Pass $(CLANG_FLAGS) to scripts/cc-can-link.sh to evaluate the link
capability for the target architecture.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
2020-07-02 00:57:45 +09:00
Mauro Carvalho Chehab
800c02f5d0 docs: move nommu-mmap.txt to admin-guide and rename to ReST
The nommu-mmap.txt file provides description of user visible
behaviuour. So, move it to the admin-guide.

As it is already at the ReST, also rename it.

Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/3a63d1833b513700755c85bf3bda0a6c4ab56986.1592918949.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-06-26 11:33:35 -06:00
Tom Rini
eacb0c101a initrd: Remove erroneous comment
Most architectures have been passing the location of an initrd via the
initrd= option since their inception.  Remove the comment as it's both
wrong and unrelated to the commit that introduced it.

For a bit more context, I assume there's been some confusion between
"initrd" being a keyword in things like extlinux.conf and also that for
quite a long time now initrd information is passed via device tree and
not the command line on relevant architectures. But it's still true that
it's been a valid command line option to the kernel since the 90s. It's
just the case that in 2018 the code was consolidated from under arch/
and in to this file.

 [ bp: Move the context clarification up into the commit message proper. ]

Fixes: 694cfd87b0c8 ("x86/setup: Add an initrdmem= option to specify initrd physical address")
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200619143056.24538-1-trini@konsulko.com
2020-06-19 19:23:54 +02:00
glider@google.com
f0fe00d497 security: allow using Clang's zero initialization for stack variables
In addition to -ftrivial-auto-var-init=pattern (used by
CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for
locals enabled by -ftrivial-auto-var-init=zero. The future of this flag
is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497).
Right now it is guarded by another flag,
-enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang,
which means it may not be supported by future Clang releases. Another
possible resolution is that -ftrivial-auto-var-init=zero will persist
(as certain users have already started depending on it), but the name
of the guard flag will change.

In the meantime, zero initialization has proven itself as a good
production mitigation measure against uninitialized locals. Unlike pattern
initialization, which has a higher chance of triggering existing bugs,
zero initialization provides safe defaults for strings, pointers, indexes,
and sizes. On the other hand, pattern initialization remains safer for
return values. Chrome OS and Android are moving to using zero
initialization for production builds.

Performance-wise, the difference between pattern and zero initialization
is usually negligible, although the generated code for zero
initialization is more compact.

This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN
and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that
enables zero initialization for locals if the corresponding flags are
supported by Clang.

Cc: Kees Cook <keescook@chromium.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-16 02:06:23 -07:00
Linus Torvalds
6adc19fd13 Kbuild updates for v5.8 (2nd)
- fix build rules in binderfs sample
 
  - fix build errors when Kbuild recurses to the top Makefile
 
  - covert '---help---' in Kconfig to 'help'
 -----BEGIN PGP SIGNATURE-----
 
 iQJJBAABCgAzFiEEbmPs18K1szRHjPqEPYsBB53g2wYFAl7lBuYVHG1hc2FoaXJv
 eUBrZXJuZWwub3JnAAoJED2LAQed4NsGHvIP/3iErjPshpg/phwH8NTCS4SFkiti
 BZRM+2lupSn7Qs53BTpVzIkXoHBJQZlJxlQ5HY8ScO+fiz28rKZr+b40us+je1Q+
 SkvSPfwZzxjEg7lAZutznG4KgItJLWJKmDyh9T8Y8TAuG4f8WO0hKnXoAp3YorS2
 zppEIxso8O5spZPjp+fF/fPbxPjIsabGK7Jp2LpSVFR5pVDHI/ycTlKQS+MFpMEx
 6JIpdFRw7TkvKew1dr5uAWT5btWHatEqjSR3JeyVHv3EICTGQwHmcHK67cJzGInK
 T51+DT7/CpKtmRgGMiTEu/INfMzzoQAKl6Fcu+vMaShTN97Hk9DpdtQyvA6P/h3L
 8GA4UBct05J7fjjIB7iUD+GYQ0EZbaFujzRXLYk+dQqEJRbhcCwvdzggGp0WvGRs
 1f8/AIpgnQv8JSL/bOMgGMS5uL2dSLsgbzTdr6RzWf1jlYdI1i4u7AZ/nBrwWP+Z
 iOBkKsVceEoJrTbaynl3eoYqFLtWyDau+//oBc2gUvmhn8ioM5dfqBRiJjxJnPG9
 /giRj6xRIqMMEw8Gg8PCG7WebfWxWyaIQwlWBbPok7DwISURK5mvOyakZL+Q25/y
 6MBr2H8NEJsf35q0GTINpfZnot7NX4JXrrndJH8NIRC7HEhwd29S041xlQJdP0rs
 E76xsOr3hrAmBu4P
 =1NIT
 -----END PGP SIGNATURE-----

Merge tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - fix build rules in binderfs sample

 - fix build errors when Kbuild recurses to the top Makefile

 - covert '---help---' in Kconfig to 'help'

* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  treewide: replace '---help---' in Kconfig files with 'help'
  kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
  samples: binderfs: really compile this sample and fix build issues
2020-06-13 13:29:16 -07:00
Masahiro Yamada
a7f7f6248d treewide: replace '---help---' in Kconfig files with 'help'
Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-14 01:57:21 +09:00
Linus Torvalds
6c32978414 Notifications over pipes + Keyring notifications
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEqG5UsNXhtOCrfGQP+7dXa6fLC2sFAl7U/i8ACgkQ+7dXa6fL
 C2u2eg/+Oy6ybq0hPovYVkFI9WIG7ZCz7w9Q6BEnfYMqqn3dnfJxKQ3l4pnQEOWw
 f4QfvpvevsYfMtOJkYcG6s66rQgbFdqc5TEyBBy0QNp3acRolN7IXkcopvv9xOpQ
 JxedpbFG1PTFLWjvBpyjlrUPouwLzq2FXAf1Ox0ZIMw6165mYOMWoli1VL8dh0A0
 Ai7JUB0WrvTNbrwhV413obIzXT/rPCdcrgbQcgrrLPex8lQ47ZAE9bq6k4q5HiwK
 KRzEqkQgnzId6cCNTFBfkTWsx89zZunz7jkfM5yx30MvdAtPSxvvpfIPdZRZkXsP
 E2K9Fk1/6OQZTC0Op3Pi/bt+hVG/mD1p0sQUDgo2MO3qlSS+5mMkR8h3mJEgwK12
 72P4YfOJkuAy2z3v4lL0GYdUDAZY6i6G8TMxERKu/a9O3VjTWICDOyBUS6F8YEAK
 C7HlbZxAEOKTVK0BTDTeEUBwSeDrBbvH6MnRlZCG5g1Fos2aWP0udhjiX8IfZLO7
 GN6nWBvK1fYzfsUczdhgnoCzQs3suoDo04HnsTPGJ8De52T4x2RsjV+gPx0nrNAq
 eWChl1JvMWsY2B3GLnl9XQz4NNN+EreKEkk+PULDGllrArrPsp5Vnhb9FJO1PVCU
 hMDJHohPiXnKbc8f4Bd78OhIvnuoGfJPdM5MtNe2flUKy2a2ops=
 =YTGf
 -----END PGP SIGNATURE-----

Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull notification queue from David Howells:
 "This adds a general notification queue concept and adds an event
  source for keys/keyrings, such as linking and unlinking keys and
  changing their attributes.

  Thanks to Debarshi Ray, we do have a pull request to use this to fix a
  problem with gnome-online-accounts - as mentioned last time:

     https://gitlab.gnome.org/GNOME/gnome-online-accounts/merge_requests/47

  Without this, g-o-a has to constantly poll a keyring-based kerberos
  cache to find out if kinit has changed anything.

  [ There are other notification pending: mount/sb fsinfo notifications
    for libmount that Karel Zak and Ian Kent have been working on, and
    Christian Brauner would like to use them in lxc, but let's see how
    this one works first ]

  LSM hooks are included:

   - A set of hooks are provided that allow an LSM to rule on whether or
     not a watch may be set. Each of these hooks takes a different
     "watched object" parameter, so they're not really shareable. The
     LSM should use current's credentials. [Wanted by SELinux & Smack]

   - A hook is provided to allow an LSM to rule on whether or not a
     particular message may be posted to a particular queue. This is
     given the credentials from the event generator (which may be the
     system) and the watch setter. [Wanted by Smack]

  I've provided SELinux and Smack with implementations of some of these
  hooks.

  WHY
  ===

  Key/keyring notifications are desirable because if you have your
  kerberos tickets in a file/directory, your Gnome desktop will monitor
  that using something like fanotify and tell you if your credentials
  cache changes.

  However, we also have the ability to cache your kerberos tickets in
  the session, user or persistent keyring so that it isn't left around
  on disk across a reboot or logout. Keyrings, however, cannot currently
  be monitored asynchronously, so the desktop has to poll for it - not
  so good on a laptop. This facility will allow the desktop to avoid the
  need to poll.

  DESIGN DECISIONS
  ================

   - The notification queue is built on top of a standard pipe. Messages
     are effectively spliced in. The pipe is opened with a special flag:

        pipe2(fds, O_NOTIFICATION_PIPE);

     The special flag has the same value as O_EXCL (which doesn't seem
     like it will ever be applicable in this context)[?]. It is given up
     front to make it a lot easier to prohibit splice&co from accessing
     the pipe.

     [?] Should this be done some other way?  I'd rather not use up a new
         O_* flag if I can avoid it - should I add a pipe3() system call
         instead?

     The pipe is then configured::

        ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
        ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);

     Messages are then read out of the pipe using read().

   - It should be possible to allow write() to insert data into the
     notification pipes too, but this is currently disabled as the
     kernel has to be able to insert messages into the pipe *without*
     holding pipe->mutex and the code to make this work needs careful
     auditing.

   - sendfile(), splice() and vmsplice() are disabled on notification
     pipes because of the pipe->mutex issue and also because they
     sometimes want to revert what they just did - but one or more
     notification messages might've been interleaved in the ring.

   - The kernel inserts messages with the wait queue spinlock held. This
     means that pipe_read() and pipe_write() have to take the spinlock
     to update the queue pointers.

   - Records in the buffer are binary, typed and have a length so that
     they can be of varying size.

     This allows multiple heterogeneous sources to share a common
     buffer; there are 16 million types available, of which I've used
     just a few, so there is scope for others to be used. Tags may be
     specified when a watchpoint is created to help distinguish the
     sources.

   - Records are filterable as types have up to 256 subtypes that can be
     individually filtered. Other filtration is also available.

   - Notification pipes don't interfere with each other; each may be
     bound to a different set of watches. Any particular notification
     will be copied to all the queues that are currently watching for it
     - and only those that are watching for it.

   - When recording a notification, the kernel will not sleep, but will
     rather mark a queue as having lost a message if there's
     insufficient space. read() will fabricate a loss notification
     message at an appropriate point later.

   - The notification pipe is created and then watchpoints are attached
     to it, using one of:

        keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
        watch_mount(AT_FDCWD, "/", 0, fd, 0x02);
        watch_sb(AT_FDCWD, "/mnt", 0, fd, 0x03);

     where in both cases, fd indicates the queue and the number after is
     a tag between 0 and 255.

   - Watches are removed if either the notification pipe is destroyed or
     the watched object is destroyed. In the latter case, a message will
     be generated indicating the enforced watch removal.

  Things I want to avoid:

   - Introducing features that make the core VFS dependent on the
     network stack or networking namespaces (ie. usage of netlink).

   - Dumping all this stuff into dmesg and having a daemon that sits
     there parsing the output and distributing it as this then puts the
     responsibility for security into userspace and makes handling
     namespaces tricky. Further, dmesg might not exist or might be
     inaccessible inside a container.

   - Letting users see events they shouldn't be able to see.

  TESTING AND MANPAGES
  ====================

   - The keyutils tree has a pipe-watch branch that has keyctl commands
     for making use of notifications. Proposed manual pages can also be
     found on this branch, though a couple of them really need to go to
     the main manpages repository instead.

     If the kernel supports the watching of keys, then running "make
     test" on that branch will cause the testing infrastructure to spawn
     a monitoring process on the side that monitors a notifications pipe
     for all the key/keyring changes induced by the tests and they'll
     all be checked off to make sure they happened.

        https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log/?h=pipe-watch

   - A test program is provided (samples/watch_queue/watch_test) that
     can be used to monitor for keyrings, mount and superblock events.
     Information on the notifications is simply logged to stdout"

* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  smack: Implement the watch_key and post_notification hooks
  selinux: Implement the watch_key security hook
  keys: Make the KEY_NEED_* perms an enum rather than a mask
  pipe: Add notification lossage handling
  pipe: Allow buffers to be marked read-whole-or-error for notifications
  Add sample notification program
  watch_queue: Add a key/keyring notification facility
  security: Add hooks to rule on setting a watch
  pipe: Add general notification queue support
  pipe: Add O_NOTIFICATION_PIPE
  security: Add a hook for the point of notification insertion
  uapi: General notification queue definitions
2020-06-13 09:56:21 -07:00
Thomas Gleixner
37d1a04b13 Rebase locking/kcsan to locking/urgent
Merge the state of the locking kcsan branch before the read/write_once()
and the atomics modifications got merged.

Squash the fallout of the rebase on top of the read/write once and atomic
fallback work into the merge. The history of the original branch is
preserved in tag locking-kcsan-2020-06-02.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-11 20:02:46 +02:00
Linus Torvalds
4152d146ee Merge branch 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux
Pull READ/WRITE_ONCE rework from Will Deacon:
 "This the READ_ONCE rework I've been working on for a while, which
  bumps the minimum GCC version and improves code-gen on arm64 when
  stack protector is enabled"

[ Side note: I'm _really_ tempted to raise the minimum gcc version to
  4.9, so that we can just say that we require _Generic() support.

  That would allow us to more cleanly handle a lot of the cases where we
  depend on very complex macros with 'sizeof' or __builtin_choose_expr()
  with __builtin_types_compatible_p() etc.

  This branch has a workaround for sparse not handling _Generic(),
  either, but that was already fixed in the sparse development branch,
  so it's really just gcc-4.9 that we'd require.   - Linus ]

* 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux:
  compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparse
  compiler_types.h: Optimize __unqual_scalar_typeof compilation time
  compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long)
  compiler-types.h: Include naked type in __pick_integer_type() match
  READ_ONCE: Fix comment describing 2x32-bit atomicity
  gcov: Remove old GCC 3.4 support
  arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros
  locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros
  READ_ONCE: Drop pointer qualifiers when reading from scalar types
  READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses
  READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE()
  arm64: csum: Disable KASAN for do_csum()
  fault_inject: Don't rely on "return value" from WRITE_ONCE()
  net: tls: Avoid assigning 'const' pointer to non-const pointer
  netfilter: Avoid assigning 'const' pointer to non-const pointer
  compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
2020-06-10 14:46:54 -07:00
Mike Rapoport
e31cf2f4ca mm: don't include asm/pgtable.h if linux/mm.h is already included
Patch series "mm: consolidate definitions of page table accessors", v2.

The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once.  For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.

Most of these definitions are actually identical and typically it boils
down to, e.g.

static inline unsigned long pmd_index(unsigned long address)
{
        return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}

static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}

These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.

For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.

These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.

This patch (of 12):

The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g.  pte_alloc() and
pmd_alloc().  So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.

The include statements in such cases are remove with a simple loop:

	for f in $(git grep -l "include <linux/mm.h>") ; do
		sed -i -e '/include <asm\/pgtable.h>/ d' $f
	done

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09 09:39:13 -07:00
Vlastimil Babka
3db978d480 kernel/sysctl: support setting sysctl parameters from kernel command line
Patch series "support setting sysctl parameters from kernel command line", v3.

This series adds support for something that seems like many people
always wanted but nobody added it yet, so here's the ability to set
sysctl parameters via kernel command line options in the form of
sysctl.vm.something=1

The important part is Patch 1.  The second, not so important part is an
attempt to clean up legacy one-off parameters that do the same thing as
a sysctl.  I don't want to remove them completely for compatibility
reasons, but with generic sysctl support the idea is to remove the
one-off param handlers and treat the parameters as aliases for the
sysctl variants.

I have identified several parameters that mention sysctl counterparts in
Documentation/admin-guide/kernel-parameters.txt but there might be more.
The conversion also has varying level of success:

 - numa_zonelist_order is converted in Patch 2 together with adding the
   necessary infrastructure. It's easy as it doesn't really do anything
   but warn on deprecated value these days.

 - hung_task_panic is converted in Patch 3, but there's a downside that
   now it only accepts 0 and 1, while previously it was any integer
   value

 - nmi_watchdog maps to two sysctls nmi_watchdog and hardlockup_panic,
   so there's no straighforward conversion possible

 - traceoff_on_warning is a flag without value and it would be required
   to handle that somehow in the conversion infractructure, which seems
   pointless for a single flag

This patch (of 5):

A recently proposed patch to add vm_swappiness command line parameter in
addition to existing sysctl [1] made me wonder why we don't have a
general support for passing sysctl parameters via command line.

Googling found only somebody else wondering the same [2], but I haven't
found any prior discussion with reasons why not to do this.

Settings the vm_swappiness issue aside (the underlying issue might be
solved in a different way), quick search of kernel-parameters.txt shows
there are already some that exist as both sysctl and kernel parameter -
hung_task_panic, nmi_watchdog, numa_zonelist_order, traceoff_on_warning.

A general mechanism would remove the need to add more of those one-offs
and might be handy in situations where configuration by e.g.
/etc/sysctl.d/ is impractical.

Hence, this patch adds a new parse_args() pass that looks for parameters
prefixed by 'sysctl.' and tries to interpret them as writes to the
corresponding sys/ files using an temporary in-kernel procfs mount.
This mechanism was suggested by Eric W.  Biederman [3], as it handles
all dynamically registered sysctl tables, even though we don't handle
modular sysctls.  Errors due to e.g.  invalid parameter name or value
are reported in the kernel log.

The processing is hooked right before the init process is loaded, as
some handlers might be more complicated than simple setters and might
need some subsystems to be initialized.  At the moment the init process
can be started and eventually execute a process writing to /proc/sys/
then it should be also fine to do that from the kernel.

Sysctls registered later on module load time are not set by this
mechanism - it's expected that in such scenarios, setting sysctl values
from userspace is practical enough.

[1] https://lore.kernel.org/r/BL0PR02MB560167492CA4094C91589930E9FC0@BL0PR02MB5601.namprd02.prod.outlook.com/
[2] https://unix.stackexchange.com/questions/558802/how-to-set-sysctl-using-kernel-command-line-parameter
[3] https://lore.kernel.org/r/87bloj2skm.fsf@x220.int.ebiederm.org/

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: "Guilherme G . Piccoli" <gpiccoli@canonical.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Link: http://lkml.kernel.org/r/20200427180433.7029-1-vbabka@suse.cz
Link: http://lkml.kernel.org/r/20200427180433.7029-2-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-08 11:05:56 -07:00
Linus Torvalds
cff11abeca Kbuild updates for v5.8
- fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32
 
  - ensure to rebuild all objects when the compiler is upgraded
 
  - exclude system headers from dependency tracking and fixdep processing
 
  - fix potential bit-size mismatch between the kernel and BPF user-mode
    helper
 
  - add the new syntax 'userprogs' to build user-space programs for the
    target architecture (the same arch as the kernel)
 
  - compile user-space sample code under samples/ for the target arch
    instead of the host arch
 
  - make headers_install fail if a CONFIG option is leaked to user-space
 
  - sanitize the output format of scripts/checkstack.pl
 
  - handle ARM 'push' instruction in scripts/checkstack.pl
 
  - error out before modpost if a module name conflict is found
 
  - error out when multiple directories are passed to M= because this
    feature is broken for a long time
 
  - add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info
 
  - a lot of cleanups of modpost
 
  - dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
    second pass of modpost
 
  - do not run the second pass of modpost if nothing in modules is updated
 
  - install modules.builtin(.modinfo) by 'make install' as well as by
    'make modules_install' because it is useful even when CONFIG_MODULES=n
 
  - add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
    to allow users to use alternatives such as pigz, pbzip2, etc.
 -----BEGIN PGP SIGNATURE-----
 
 iQJJBAABCgAzFiEEbmPs18K1szRHjPqEPYsBB53g2wYFAl7brm0VHG1hc2FoaXJv
 eUBrZXJuZWwub3JnAAoJED2LAQed4NsGjeEP/Rrf8H9cp/Tq+ALQCBycI3W5ZEHg
 n2EqprZkVP2MlOV0d+8b9t4PdZf6E5Wmfv26sMaBAhl6X1KQI/0NgPMnTINvy5jJ
 Q2SMhj9y8Gwr3XKFu9Hd/0U+Sax5rz+LmY84tdF95dXzPIUWjAEVnbmN+ofY6T++
 sNf2YGNFSR6iiqr3uCYA0hHZmpKlfhVgDPAdncWa5aadSsuQb79nZQWefGeVEsuD
 HrISpwnkhBc0qY1xyWry6agE92xWmkNkdjKq6A7peguZL02XySWLRWjyHoiiaPOB
 6U4urKs/NSXqPgxGxwZthhwERHryC3+g4s8wRBDKE6ISRWKBBA2ruHpgdF5h/utu
 re1ZP2qRcAt8NBFynr4MEb2AU0mYkv7iEgfLJ7NUCRlMOtqrn5RFwnS4r8ReyQp5
 1UM11RbPhYgYjM5g9hBHJ7nK944/kfvy1/4jF4I1+M5O7QL6f00pu3r2bBIa/65g
 DWrNOpIliKG27GgnRlxi7HgLfxs9etFcXTpHO0ymgnMmlz+7FQsdceR9qqybGU9o
 yBWw6zculMQjb3E+k0DTnE5kLWsycbua921wxM9ABSxRmJi7WciNF73RdLUIBoAY
 VUbwrP2aIpdL+2uyX6RqdTaWzEBpW8omszr46aQ96pX+RiqMrPvJRLaA/tr3ZH8g
 tdHenJPWdHSaOcO4
 =GKe5
 -----END PGP SIGNATURE-----

Merge tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32

 - ensure to rebuild all objects when the compiler is upgraded

 - exclude system headers from dependency tracking and fixdep processing

 - fix potential bit-size mismatch between the kernel and BPF user-mode
   helper

 - add the new syntax 'userprogs' to build user-space programs for the
   target architecture (the same arch as the kernel)

 - compile user-space sample code under samples/ for the target arch
   instead of the host arch

 - make headers_install fail if a CONFIG option is leaked to user-space

 - sanitize the output format of scripts/checkstack.pl

 - handle ARM 'push' instruction in scripts/checkstack.pl

 - error out before modpost if a module name conflict is found

 - error out when multiple directories are passed to M= because this
   feature is broken for a long time

 - add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info

 - a lot of cleanups of modpost

 - dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
   second pass of modpost

 - do not run the second pass of modpost if nothing in modules is
   updated

 - install modules.builtin(.modinfo) by 'make install' as well as by
   'make modules_install' because it is useful even when
   CONFIG_MODULES=n

 - add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
   to allow users to use alternatives such as pigz, pbzip2, etc.

* tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits)
  kbuild: add variables for compression tools
  Makefile: install modules.builtin even if CONFIG_MODULES=n
  mksysmap: Fix the mismatch of '.L' symbols in System.map
  kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS
  modpost: change elf_info->size to size_t
  modpost: remove is_vmlinux() helper
  modpost: strip .o from modname before calling new_module()
  modpost: set have_vmlinux in new_module()
  modpost: remove mod->skip struct member
  modpost: add mod->is_vmlinux struct member
  modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()
  modpost: remove mod->is_dot_o struct member
  modpost: move -d option in scripts/Makefile.modpost
  modpost: remove -s option
  modpost: remove get_next_text() and make {grab,release_}file static
  modpost: use read_text_file() and get_line() for reading text files
  modpost: avoid false-positive file open error
  modpost: fix potential mmap'ed file overrun in get_src_version()
  modpost: add read_text_file() and get_line() helpers
  modpost: do not call get_modinfo() for vmlinux(.o)
  ...
2020-06-06 12:00:25 -07:00
Nick Desaulniers
587f17018a Kconfig: add config option for asm goto w/ outputs
This allows C code to make use of compilers with support for output
variables along the fallthrough path via preprocessor define:

  CONFIG_CC_HAS_ASM_GOTO_OUTPUT

[ This is not used anywhere yet, and currently released compilers don't
  support this yet, but it's coming, and I have some local experimental
  patches to take advantage of it when it does   - Linus ]

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04 19:28:07 -07:00
Chris Down
ada4ab7af1 init: allow distribution configuration of default init
Some init systems (eg.  systemd) have init at their own paths, for
example, /usr/lib/systemd/systemd.  A compatibility symlink to one of the
hardcoded init paths is provided by another package, usually named
something like systemd-sysvcompat or similar.

Currently distro maintainers who are hands-off on the bootloader are more
or less required to include those compatibility links as part of their
base distribution, because it's hard to migrate away from them since
there's a risk some users will not get the message to set init= on the
kernel command line appropriately.

Moreover, for distributions where the init system is something the
distribution itself is opinionated about (eg.  Arch, which has systemd in
the required `base` package), we could usually reasonably configure this
ahead of time when building the distribution kernel.  However, we
currently simply don't have any way to configure the kernel to do this.
Here's an example discussion where removing sysvcompat was discussed by
distro maintainers[0].

This patch adds a new Kconfig tunable, CONFIG_DEFAULT_INIT, which if set
is tried before the hardcoded fallback list.  So the order of precedence
is now thus:

1. init= on command line (on failure: panic)
2. CONFIG_DEFAULT_INIT (on failure: try #3)
3. Hardcoded fallback list (on failure: panic)

This new config parameter will allow distribution maintainers to move away
from these compatibility links safely, without having to worry that their
users might not have the right init=.

There are also two other benefits of this over having the distribution
maintain a symlink:

1. One of the value propositions over simply having distributions
   maintain a /sbin/init symlink via a package is that it also frees
   distributions which have a preferred default, but not mandatory, init
   system from having their package manager fight with their users for
   control of /{s,}bin/init.  Instead, the distribution simply makes
   their preference known in CONFIG_DEFAULT_INIT, and if the user
   installs another init system and uninstalls the default one they can
   still make use of /{s,}bin/init and friends for their own uses. This
   makes more cases Just Work(tm) without the user having to perform
   extra configuration via init=.

2. Since before this we don't know which path the distribution actually
   _intends_ to serve init from, we don't pr_err if it is simply
   missing, and usually will just silently put the user in a /bin/sh
   shell. Now that the distribution can make a declaration of intent, we
   can be more vocal when this init system fails to launch for any
   reason, even if it's simply because no file exists at that location,
   speeding up the palaver of init/mount dependency/etc debugging a bit.

[0]: https://lists.archlinux.org/pipermail/arch-dev-public/2019-January/029435.html

Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: http://lkml.kernel.org/r/20200522160234.GA1487022@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04 19:06:25 -07:00
Linus Torvalds
ee01c4d72a Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "More mm/ work, plenty more to come

  Subsystems affected by this patch series: slub, memcg, gup, kasan,
  pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs,
  thp, mmap, kconfig"

* akpm: (131 commits)
  arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
  x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
  riscv: support DEBUG_WX
  mm: add DEBUG_WX support
  drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup
  mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid()
  powerpc/mm: drop platform defined pmd_mknotpresent()
  mm: thp: don't need to drain lru cache when splitting and mlocking THP
  hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs
  sparc32: register memory occupied by kernel as memblock.memory
  include/linux/memblock.h: fix minor typo and unclear comment
  mm, mempolicy: fix up gup usage in lookup_node
  tools/vm/page_owner_sort.c: filter out unneeded line
  mm: swap: memcg: fix memcg stats for huge pages
  mm: swap: fix vmstats for huge pages
  mm: vmscan: limit the range of LRU type balancing
  mm: vmscan: reclaim writepage is IO cost
  mm: vmscan: determine anon/file pressure balance at the reclaim root
  mm: balance LRU lists based on relative thrashing
  mm: only count actual rotations as LRU reclaim cost
  ...
2020-06-03 20:24:15 -07:00
Johannes Weiner
2d1c498072 mm: memcontrol: make swap tracking an integral part of memory control
Without swap page tracking, users that are otherwise memory controlled can
easily escape their containment and allocate significant amounts of memory
that they're not being charged for.  That's because swap does readahead,
but without the cgroup records of who owned the page at swapout, readahead
pages don't get charged until somebody actually faults them into their
page table and we can identify an owner task.  This can be maliciously
exploited with MADV_WILLNEED, which triggers arbitrary readahead
allocations without charging the pages.

Make swap swap page tracking an integral part of memcg and remove the
Kconfig options.  In the first place, it was only made configurable to
allow users to save some memory.  But the overhead of tracking cgroup
ownership per swap page is minimal - 2 byte per page, or 512k per 1G of
swap, or 0.04%.  Saving that at the expense of broken containment
semantics is not something we should present as a coequal option.

The swapaccount=0 boot option will continue to exist, and it will
eliminate the page_counter overhead and hide the swap control files, but
it won't disable swap slot ownership tracking.

This patch makes sure we always have the cgroup records at swapin time;
the next patch will fix the actual bug by charging readahead swap pages at
swapin time rather than at fault time.

v2: fix double swap charge bug in cgroup1/cgroup2 code gating

[hannes@cmpxchg.org: fix crash with cgroup_disable=memory]
  Link: http://lkml.kernel.org/r/20200521215855.GB815153@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: http://lkml.kernel.org/r/20200508183105.225460-16-hannes@cmpxchg.org
Debugged-by: Hugh Dickins <hughd@google.com>
Debugged-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-03 20:09:48 -07:00
Daniel Jordan
f1b192b117 padata: initialize earlier
padata will soon initialize the system's struct pages in parallel, so it
needs to be ready by page_alloc_init_late().

The error return from padata_driver_init() triggers an initcall warning,
so add a warning to padata_init() to avoid silent failure.

Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Josh Triplett <josh@joshtriplett.org>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Shile Zhang <shile.zhang@linux.alibaba.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Link: http://lkml.kernel.org/r/20200527173608.2885243-3-daniel.m.jordan@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-03 20:09:45 -07:00
Linus Torvalds
8226f11318 MIPS updates for v5.8:
- added support for MIPSr5 and P5600 cores
 - converted Loongson PCI driver into a PCI host driver using the generic
   PCI framework
 - added emulation of CPUCFG command for Loogonson64 cpus
 - removed of LASAT, PMC MSP71xx and NEC MARKEINS/EMMA
 - ioremap cleanup
 - fix for a race between two threads faulting the same page
 - various cleanups and fixes
 -----BEGIN PGP SIGNATURE-----
 
 iQJOBAABCAA4FiEEbt46xwy6kEcDOXoUeZbBVTGwZHAFAl7WK54aHHRzYm9nZW5k
 QGFscGhhLmZyYW5rZW4uZGUACgkQeZbBVTGwZHAbjA/9EEFeqNg9UNUH6/TS18QV
 qkxKp0+LC4Jk+SduzLyYsYy6l/dSaKYl8m9jyJsWjM6BvBZTcMJJOnzIPRafI0s+
 MK8GCSZunAkm25DsDvfobQUkbQ/UHjY/fuRpNslbDcsYqIKv90hUMd21ccXY6KC5
 RY+aMlpjgksg1X8JJ7k1Rs05sXyUPqpESteyqehF1b/+Iyv7H2L3v5EvQwvPDs6f
 TyVgNJU2B3RCU6/uAcWmHdVLxXd+Y8fM0vC8DCO0pg0rGf4be0FbZztHmeq6r2wy
 g7wsO7acKWGzulFQD5ftVSQ6i8KHIDNDePmDMtU5oFcXkzUDdGvd3j3Gst19/nve
 ZftNmQHOY1JqGUOhdq1fDG/4M3Vc5bvh3W6eMG22TuMLEWsOF8teY8uUa/vxOb+B
 2NsJ9q6ylRS7RDWWOrApJWfFYPvhr5wlLxT+azWNa9y3bjV8vDLjNdU0mRLA1nsu
 yLzYMwIhtWfZhkJZ+xJVSmQ6LjAHDN5TF/LEx/9itLg5t9wrEosFPAtOv8V15hy4
 KBNvvWeoy7RRmBTNuKh7r9Ui4jw7GgxL4D1OwzCsF//GAiGyuuh0zMuUE8EXA6K5
 MpdGt+bSOcLl8ILTtGir8e4MXLawDH8n94f8QWLb9FcOvU4KHUjRKU7EQ6dyD5dk
 a7xskGLXWdVO3IJ/Xvxcaeo=
 =eAtN
 -----END PGP SIGNATURE-----

Merge tag 'mips_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

Pull MIPS updates from Thomas Bogendoerfer:

 - added support for MIPSr5 and P5600 cores

 - converted Loongson PCI driver into a PCI host driver using the
   generic PCI framework

 - added emulation of CPUCFG command for Loogonson64 cpus

 - removed of LASAT, PMC MSP71xx and NEC MARKEINS/EMMA

 - ioremap cleanup

 - fix for a race between two threads faulting the same page

 - various cleanups and fixes

* tag 'mips_5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (143 commits)
  MIPS: ralink: drop ralink_clk_init for mt7621
  MIPS: ralink: bootrom: mark a function as __init to save some memory
  MIPS: Loongson64: Reorder CPUCFG model match arms
  MIPS: Expose Loongson CPUCFG availability via HWCAP
  MIPS: Loongson64: Guard against future cores without CPUCFG
  MIPS: Fix build warning about "PTR_STR" redefinition
  MIPS: Loongson64: Remove not used pci.c
  MIPS: Loongson64: Define PCI_IOBASE
  MIPS: CPU_LOONGSON2EF need software to maintain cache consistency
  MIPS: DTS: Fix build errors used with various configs
  MIPS: Loongson64: select NO_EXCEPT_FILL
  MIPS: Fix IRQ tracing when call handle_fpe() and handle_msa_fpe()
  MIPS: mm: add page valid judgement in function pte_modify
  mm/memory.c: Add memory read privilege on page fault handling
  mm/memory.c: Update local TLB if PTE entry exists
  MIPS: Do not flush tlb page when updating PTE entry
  MIPS: ingenic: Default to a generic board
  MIPS: ingenic: Add support for GCW Zero prototype
  MIPS: ingenic: DTS: Add memory info of GCW Zero
  MIPS: Loongson64: Switch to generic PCI driver
  ...
2020-06-03 13:32:21 -07:00