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43429 Commits

Author SHA1 Message Date
Jakub Kicinski
c49b292d03 netdev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2023-12-18

This PR is larger than usual and contains changes in various parts
of the kernel.

The main changes are:

1) Fix kCFI bugs in BPF, from Peter Zijlstra.

End result: all forms of indirect calls from BPF into kernel
and from kernel into BPF work with CFI enabled. This allows BPF
to work with CONFIG_FINEIBT=y.

2) Introduce BPF token object, from Andrii Nakryiko.

It adds an ability to delegate a subset of BPF features from privileged
daemon (e.g., systemd) through special mount options for userns-bound
BPF FS to a trusted unprivileged application. The design accommodates
suggestions from Christian Brauner and Paul Moore.

Example:
$ sudo mkdir -p /sys/fs/bpf/token
$ sudo mount -t bpf bpffs /sys/fs/bpf/token \
             -o delegate_cmds=prog_load:MAP_CREATE \
             -o delegate_progs=kprobe \
             -o delegate_attachs=xdp

3) Various verifier improvements and fixes, from Andrii Nakryiko, Andrei Matei.

 - Complete precision tracking support for register spills
 - Fix verification of possibly-zero-sized stack accesses
 - Fix access to uninit stack slots
 - Track aligned STACK_ZERO cases as imprecise spilled registers.
   It improves the verifier "instructions processed" metric from single
   digit to 50-60% for some programs.
 - Fix verifier retval logic

4) Support for VLAN tag in XDP hints, from Larysa Zaremba.

5) Allocate BPF trampoline via bpf_prog_pack mechanism, from Song Liu.

End result: better memory utilization and lower I$ miss for calls to BPF
via BPF trampoline.

6) Fix race between BPF prog accessing inner map and parallel delete,
from Hou Tao.

7) Add bpf_xdp_get_xfrm_state() kfunc, from Daniel Xu.

It allows BPF interact with IPSEC infra. The intent is to support
software RSS (via XDP) for the upcoming ipsec pcpu work.
Experiments on AWS demonstrate single tunnel pcpu ipsec reaching
line rate on 100G ENA nics.

8) Expand bpf_cgrp_storage to support cgroup1 non-attach, from Yafang Shao.

9) BPF file verification via fsverity, from Song Liu.

It allows BPF progs get fsverity digest.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (164 commits)
  bpf: Ensure precise is reset to false in __mark_reg_const_zero()
  selftests/bpf: Add more uprobe multi fail tests
  bpf: Fail uprobe multi link with negative offset
  selftests/bpf: Test the release of map btf
  s390/bpf: Fix indirect trampoline generation
  selftests/bpf: Temporarily disable dummy_struct_ops test on s390
  x86/cfi,bpf: Fix bpf_exception_cb() signature
  bpf: Fix dtor CFI
  cfi: Add CFI_NOSEAL()
  x86/cfi,bpf: Fix bpf_struct_ops CFI
  x86/cfi,bpf: Fix bpf_callback_t CFI
  x86/cfi,bpf: Fix BPF JIT call
  cfi: Flip headers
  selftests/bpf: Add test for abnormal cnt during multi-kprobe attachment
  selftests/bpf: Don't use libbpf_get_error() in kprobe_multi_test
  selftests/bpf: Add test for abnormal cnt during multi-uprobe attachment
  bpf: Limit the number of kprobes when attaching program to multiple kprobes
  bpf: Limit the number of uprobes when attaching program to multiple uprobes
  bpf: xdp: Register generic_kfunc_set with XDP programs
  selftests/bpf: utilize string values for delegate_xxx mount options
  ...
====================

Link: https://lore.kernel.org/r/20231219000520.34178-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-18 16:46:08 -08:00
Andrii Nakryiko
8e432e6197 bpf: Ensure precise is reset to false in __mark_reg_const_zero()
It is safe to always start with imprecise SCALAR_VALUE register.
Previously __mark_reg_const_zero() relied on caller to reset precise
mark, but it's very error prone and we already missed it in a few
places. So instead make __mark_reg_const_zero() reset precision always,
as it's a safe default for SCALAR_VALUE. Explanation is basically the
same as for why we are resetting (or rather not setting) precision in
current state. If necessary, precision propagation will set it to
precise correctly.

As such, also remove a big comment about forward precision propagation
in mark_reg_stack_read() and avoid unnecessarily setting precision to
true after reading from STACK_ZERO stack. Again, precision propagation
will correctly handle this, if that SCALAR_VALUE register will ever be
needed to be precise.

Reported-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20231218173601.53047-1-andrii@kernel.org
2023-12-18 23:54:21 +01:00
Jiri Olsa
3983c00281 bpf: Fail uprobe multi link with negative offset
Currently the __uprobe_register will return 0 (success) when called with
negative offset. The reason is that the call to register_for_each_vma and
then build_map_info won't return error for negative offset. They just won't
do anything - no matching vma is found so there's no registered breakpoint
for the uprobe.

I don't think we can change the behaviour of __uprobe_register and fail
for negative uprobe offset, because apps might depend on that already.

But I think we can still make the change and check for it on bpf multi
link syscall level.

Also moving the __get_user call and check for the offsets to the top of
loop, to fail early without extra __get_user calls for ref_ctr_offset
and cookie arrays.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20231217215538.3361991-2-jolsa@kernel.org
2023-12-18 09:51:30 -08:00
Alexei Starovoitov
852486b35f x86/cfi,bpf: Fix bpf_exception_cb() signature
As per the earlier patches, BPF sub-programs have bpf_callback_t
signature and CFI expects callers to have matching signature. This is
violated by bpf_prog_aux::bpf_exception_cb().

[peterz: Changelog]
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/CAADnVQ+Z7UcXXBBhMubhcMM=R-dExk-uHtfOLtoLxQ1XxEpqEA@mail.gmail.com
Link: https://lore.kernel.org/r/20231215092707.910319166@infradead.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-15 16:25:55 -08:00
Peter Zijlstra
e4c0033989 bpf: Fix dtor CFI
Ensure the various dtor functions match their prototype and retain
their CFI signatures, since they don't have their address taken, they
are prone to not getting CFI, making them impossible to call
indirectly.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231215092707.799451071@infradead.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-15 16:25:55 -08:00
Peter Zijlstra
2cd3e3772e x86/cfi,bpf: Fix bpf_struct_ops CFI
BPF struct_ops uses __arch_prepare_bpf_trampoline() to write
trampolines for indirect function calls. These tramplines much have
matching CFI.

In order to obtain the correct CFI hash for the various methods, add a
matching structure that contains stub functions, the compiler will
generate correct CFI which we can pilfer for the trampolines.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231215092707.566977112@infradead.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-15 16:25:55 -08:00
Peter Zijlstra
4f9087f166 x86/cfi,bpf: Fix BPF JIT call
The current BPF call convention is __nocfi, except when it calls !JIT things,
then it calls regular C functions.

It so happens that with FineIBT the __nocfi and C calling conventions are
incompatible. Specifically __nocfi will call at func+0, while FineIBT will have
endbr-poison there, which is not a valid indirect target. Causing #CP.

Notably this only triggers on IBT enabled hardware, which is probably why this
hasn't been reported (also, most people will have JIT on anyway).

Implement proper CFI prologues for the BPF JIT codegen and drop __nocfi for
x86.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20231215092707.345270396@infradead.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-15 16:25:55 -08:00
Hou Tao
d6d1e6c17c bpf: Limit the number of kprobes when attaching program to multiple kprobes
An abnormally big cnt may also be assigned to kprobe_multi.cnt when
attaching multiple kprobes. It will trigger the following warning in
kvmalloc_node():

	if (unlikely(size > INT_MAX)) {
	    WARN_ON_ONCE(!(flags & __GFP_NOWARN));
	    return NULL;
	}

Fix the warning by limiting the maximal number of kprobes in
bpf_kprobe_multi_link_attach(). If the number of kprobes is greater than
MAX_KPROBE_MULTI_CNT, the attachment will fail and return -E2BIG.

Fixes: 0dcac27254 ("bpf: Add multi kprobe link")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231215100708.2265609-3-houtao@huaweicloud.com
2023-12-15 22:54:55 +01:00
Hou Tao
8b2efe51ba bpf: Limit the number of uprobes when attaching program to multiple uprobes
An abnormally big cnt may be passed to link_create.uprobe_multi.cnt,
and it will trigger the following warning in kvmalloc_node():

	if (unlikely(size > INT_MAX)) {
		WARN_ON_ONCE(!(flags & __GFP_NOWARN));
		return NULL;
	}

Fix the warning by limiting the maximal number of uprobes in
bpf_uprobe_multi_link_attach(). If the number of uprobes is greater than
MAX_UPROBE_MULTI_CNT, the attachment will return -E2BIG.

Fixes: 89ae89f53d ("bpf: Add multi uprobe link")
Reported-by: Xingwei Lee <xrivendell7@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3YiNVA@mail.gmail.com
Link: https://lore.kernel.org/bpf/20231215100708.2265609-2-houtao@huaweicloud.com
2023-12-15 22:54:46 +01:00
Daniel Xu
7489723c2e bpf: xdp: Register generic_kfunc_set with XDP programs
Registering generic_kfunc_set with XDP programs enables some of the
newer BPF features inside XDP -- namely tree based data structures and
BPF exceptions.

The current motivation for this commit is to enable assertions inside
XDP bpf progs. Assertions are a standard and useful tool to encode
intent.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/d07d4614b81ca6aada44fcb89bb6b618fb66e4ca.1702594357.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-14 19:12:16 -08:00
Andrii Nakryiko
c5707b2146 bpf: support symbolic BPF FS delegation mount options
Besides already supported special "any" value and hex bit mask, support
string-based parsing of delegation masks based on exact enumerator
names. Utilize BTF information of `enum bpf_cmd`, `enum bpf_map_type`,
`enum bpf_prog_type`, and `enum bpf_attach_type` types to find supported
symbolic names (ignoring __MAX_xxx guard values and stripping repetitive
prefixes like BPF_ for cmd and attach types, BPF_MAP_TYPE_ for maps, and
BPF_PROG_TYPE_ for prog types). The case doesn't matter, but it is
normalized to lower case in mount option output. So "PROG_LOAD",
"prog_load", and "MAP_create" are all valid values to specify for
delegate_cmds options, "array" is among supported for map types, etc.

Besides supporting string values, we also support multiple values
specified at the same time, using colon (':') separator.

There are corresponding changes on bpf_show_options side to use known
values to print them in human-readable format, falling back to hex mask
printing, if there are any unrecognized bits. This shouldn't be
necessary when enum BTF information is present, but in general we should
always be able to fall back to this even if kernel was built without BTF.
As mentioned, emitted symbolic names are normalized to be all lower case.

Example below shows various ways to specify delegate_cmds options
through mount command and how mount options are printed back:

12/14 14:39:07.604
vmuser@archvm:~/local/linux/tools/testing/selftests/bpf
$ mount | rg token

  $ sudo mkdir -p /sys/fs/bpf/token
  $ sudo mount -t bpf bpffs /sys/fs/bpf/token \
               -o delegate_cmds=prog_load:MAP_CREATE \
               -o delegate_progs=kprobe \
               -o delegate_attachs=xdp
  $ mount | grep token
  bpffs on /sys/fs/bpf/token type bpf (rw,relatime,delegate_cmds=map_create:prog_load,delegate_progs=kprobe,delegate_attachs=xdp)

Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231214225016.1209867-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-14 17:30:27 -08:00
Jakub Kicinski
8f674972d6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

Conflicts:

drivers/net/ethernet/intel/iavf/iavf_ethtool.c
  3a0b5a2929 ("iavf: Introduce new state machines for flow director")
  95260816b4 ("iavf: use iavf_schedule_aq_request() helper")
https://lore.kernel.org/all/84e12519-04dc-bd80-bc34-8cf50d7898ce@intel.com/

drivers/net/ethernet/broadcom/bnxt/bnxt.c
  c13e268c07 ("bnxt_en: Fix HWTSTAMP_FILTER_ALL packet timestamp logic")
  c2f8063309 ("bnxt_en: Refactor RX VLAN acceleration logic.")
  a7445d6980 ("bnxt_en: Add support for new RX and TPA_START completion types for P7")
  1c7fd6ee2f ("bnxt_en: Rename some macros for the P5 chips")
https://lore.kernel.org/all/20231211110022.27926ad9@canb.auug.org.au/

drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
  bd6781c18c ("bnxt_en: Fix wrong return value check in bnxt_close_nic()")
  84793a4995 ("bnxt_en: Skip nic close/open when configuring tstamp filters")
https://lore.kernel.org/all/20231214113041.3a0c003c@canb.auug.org.au/

drivers/net/ethernet/mellanox/mlx5/core/fw_reset.c
  3d7a3f2612 ("net/mlx5: Nack sync reset request when HotPlug is enabled")
  cecf44ea1a ("net/mlx5: Allow sync reset flow when BF MGT interface device is present")
https://lore.kernel.org/all/20231211110328.76c925af@canb.auug.org.au/

No adjacent changes.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-14 17:14:41 -08:00
Yonghong Song
59e5791f59 bpf: Fix a race condition between btf_put() and map_free()
When running `./test_progs -j` in my local vm with latest kernel,
I once hit a kasan error like below:

  [ 1887.184724] BUG: KASAN: slab-use-after-free in bpf_rb_root_free+0x1f8/0x2b0
  [ 1887.185599] Read of size 4 at addr ffff888106806910 by task kworker/u12:2/2830
  [ 1887.186498]
  [ 1887.186712] CPU: 3 PID: 2830 Comm: kworker/u12:2 Tainted: G           OEL     6.7.0-rc3-00699-g90679706d486-dirty #494
  [ 1887.188034] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [ 1887.189618] Workqueue: events_unbound bpf_map_free_deferred
  [ 1887.190341] Call Trace:
  [ 1887.190666]  <TASK>
  [ 1887.190949]  dump_stack_lvl+0xac/0xe0
  [ 1887.191423]  ? nf_tcp_handle_invalid+0x1b0/0x1b0
  [ 1887.192019]  ? panic+0x3c0/0x3c0
  [ 1887.192449]  print_report+0x14f/0x720
  [ 1887.192930]  ? preempt_count_sub+0x1c/0xd0
  [ 1887.193459]  ? __virt_addr_valid+0xac/0x120
  [ 1887.194004]  ? bpf_rb_root_free+0x1f8/0x2b0
  [ 1887.194572]  kasan_report+0xc3/0x100
  [ 1887.195085]  ? bpf_rb_root_free+0x1f8/0x2b0
  [ 1887.195668]  bpf_rb_root_free+0x1f8/0x2b0
  [ 1887.196183]  ? __bpf_obj_drop_impl+0xb0/0xb0
  [ 1887.196736]  ? preempt_count_sub+0x1c/0xd0
  [ 1887.197270]  ? preempt_count_sub+0x1c/0xd0
  [ 1887.197802]  ? _raw_spin_unlock+0x1f/0x40
  [ 1887.198319]  bpf_obj_free_fields+0x1d4/0x260
  [ 1887.198883]  array_map_free+0x1a3/0x260
  [ 1887.199380]  bpf_map_free_deferred+0x7b/0xe0
  [ 1887.199943]  process_scheduled_works+0x3a2/0x6c0
  [ 1887.200549]  worker_thread+0x633/0x890
  [ 1887.201047]  ? __kthread_parkme+0xd7/0xf0
  [ 1887.201574]  ? kthread+0x102/0x1d0
  [ 1887.202020]  kthread+0x1ab/0x1d0
  [ 1887.202447]  ? pr_cont_work+0x270/0x270
  [ 1887.202954]  ? kthread_blkcg+0x50/0x50
  [ 1887.203444]  ret_from_fork+0x34/0x50
  [ 1887.203914]  ? kthread_blkcg+0x50/0x50
  [ 1887.204397]  ret_from_fork_asm+0x11/0x20
  [ 1887.204913]  </TASK>
  [ 1887.204913]  </TASK>
  [ 1887.205209]
  [ 1887.205416] Allocated by task 2197:
  [ 1887.205881]  kasan_set_track+0x3f/0x60
  [ 1887.206366]  __kasan_kmalloc+0x6e/0x80
  [ 1887.206856]  __kmalloc+0xac/0x1a0
  [ 1887.207293]  btf_parse_fields+0xa15/0x1480
  [ 1887.207836]  btf_parse_struct_metas+0x566/0x670
  [ 1887.208387]  btf_new_fd+0x294/0x4d0
  [ 1887.208851]  __sys_bpf+0x4ba/0x600
  [ 1887.209292]  __x64_sys_bpf+0x41/0x50
  [ 1887.209762]  do_syscall_64+0x4c/0xf0
  [ 1887.210222]  entry_SYSCALL_64_after_hwframe+0x63/0x6b
  [ 1887.210868]
  [ 1887.211074] Freed by task 36:
  [ 1887.211460]  kasan_set_track+0x3f/0x60
  [ 1887.211951]  kasan_save_free_info+0x28/0x40
  [ 1887.212485]  ____kasan_slab_free+0x101/0x180
  [ 1887.213027]  __kmem_cache_free+0xe4/0x210
  [ 1887.213514]  btf_free+0x5b/0x130
  [ 1887.213918]  rcu_core+0x638/0xcc0
  [ 1887.214347]  __do_softirq+0x114/0x37e

The error happens at bpf_rb_root_free+0x1f8/0x2b0:

  00000000000034c0 <bpf_rb_root_free>:
  ; {
    34c0: f3 0f 1e fa                   endbr64
    34c4: e8 00 00 00 00                callq   0x34c9 <bpf_rb_root_free+0x9>
    34c9: 55                            pushq   %rbp
    34ca: 48 89 e5                      movq    %rsp, %rbp
  ...
  ;       if (rec && rec->refcount_off >= 0 &&
    36aa: 4d 85 ed                      testq   %r13, %r13
    36ad: 74 a9                         je      0x3658 <bpf_rb_root_free+0x198>
    36af: 49 8d 7d 10                   leaq    0x10(%r13), %rdi
    36b3: e8 00 00 00 00                callq   0x36b8 <bpf_rb_root_free+0x1f8>
                                        <==== kasan function
    36b8: 45 8b 7d 10                   movl    0x10(%r13), %r15d
                                        <==== use-after-free load
    36bc: 45 85 ff                      testl   %r15d, %r15d
    36bf: 78 8c                         js      0x364d <bpf_rb_root_free+0x18d>

So the problem is at rec->refcount_off in the above.

I did some source code analysis and find the reason.
                                  CPU A                        CPU B
  bpf_map_put:
    ...
    btf_put with rcu callback
    ...
    bpf_map_free_deferred
      with system_unbound_wq
    ...                          ...                           ...
    ...                          btf_free_rcu:                 ...
    ...                          ...                           bpf_map_free_deferred:
    ...                          ...
    ...         --------->       btf_struct_metas_free()
    ...         | race condition ...
    ...         --------->                                     map->ops->map_free()
    ...
    ...                          btf->struct_meta_tab = NULL

In the above, map_free() corresponds to array_map_free() and eventually
calling bpf_rb_root_free() which calls:
  ...
  __bpf_obj_drop_impl(obj, field->graph_root.value_rec, false);
  ...

Here, 'value_rec' is assigned in btf_check_and_fixup_fields() with following code:

  meta = btf_find_struct_meta(btf, btf_id);
  if (!meta)
    return -EFAULT;
  rec->fields[i].graph_root.value_rec = meta->record;

So basically, 'value_rec' is a pointer to the record in struct_metas_tab.
And it is possible that that particular record has been freed by
btf_struct_metas_free() and hence we have a kasan error here.

Actually it is very hard to reproduce the failure with current bpf/bpf-next
code, I only got the above error once. To increase reproducibility, I added
a delay in bpf_map_free_deferred() to delay map->ops->map_free(), which
significantly increased reproducibility.

  diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
  index 5e43ddd1b83f..aae5b5213e93 100644
  --- a/kernel/bpf/syscall.c
  +++ b/kernel/bpf/syscall.c
  @@ -695,6 +695,7 @@ static void bpf_map_free_deferred(struct work_struct *work)
        struct bpf_map *map = container_of(work, struct bpf_map, work);
        struct btf_record *rec = map->record;

  +     mdelay(100);
        security_bpf_map_free(map);
        bpf_map_release_memcg(map);
        /* implementation dependent freeing */

Hao also provided test cases ([1]) for easily reproducing the above issue.

There are two ways to fix the issue, the v1 of the patch ([2]) moving
btf_put() after map_free callback, and the v5 of the patch ([3]) using
a kptr style fix which tries to get a btf reference during
map_check_btf(). Each approach has its pro and cons. The first approach
delays freeing btf while the second approach needs to acquire reference
depending on context which makes logic not very elegant and may
complicate things with future new data structures. Alexei
suggested in [4] going back to v1 which is what this patch
tries to do.

Rerun './test_progs -j' with the above mdelay() hack for a couple
of times and didn't observe the error for the above rb_root test cases.
Running Hou's test ([1]) is also successful.

  [1] https://lore.kernel.org/bpf/20231207141500.917136-1-houtao@huaweicloud.com/
  [2] v1: https://lore.kernel.org/bpf/20231204173946.3066377-1-yonghong.song@linux.dev/
  [3] v5: https://lore.kernel.org/bpf/20231208041621.2968241-1-yonghong.song@linux.dev/
  [4] v4: https://lore.kernel.org/bpf/CAADnVQJ3FiXUhZJwX_81sjZvSYYKCFB3BT6P8D59RS2Gu+0Z7g@mail.gmail.com/

Cc: Hou Tao <houtao@huaweicloud.com>
Fixes: 958cf2e273 ("bpf: Introduce bpf_obj_new")
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20231214203815.1469107-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-14 17:10:32 -08:00
Hou Tao
dc68540913 bpf: Use GFP_KERNEL in bpf_event_entry_gen()
rcu_read_lock() is no longer held when invoking bpf_event_entry_gen()
which is called by perf_event_fd_array_get_ptr(), so using GFP_KERNEL
instead of GFP_ATOMIC to reduce the possibility of failures due to
out-of-memory.

Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231214043010.3458072-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-13 20:49:11 -08:00
Hou Tao
8f82583f95 bpf: Reduce the scope of rcu_read_lock when updating fd map
There is no rcu-read-lock requirement for ops->map_fd_get_ptr() or
ops->map_fd_put_ptr(), so doesn't use rcu-read-lock for these two
callbacks.

For bpf_fd_array_map_update_elem(), accessing array->ptrs doesn't need
rcu-read-lock because array->ptrs must still be allocated. For
bpf_fd_htab_map_update_elem(), htab_map_update_elem() only requires
rcu-read-lock to be held to avoid the WARN_ON_ONCE(), so only use
rcu_read_lock() during the invocation of htab_map_update_elem().

Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231214043010.3458072-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-13 20:49:11 -08:00
Hou Tao
2a0c6b41ee bpf: Update the comments in maybe_wait_bpf_programs()
Since commit 638e4b825d ("bpf: Allows per-cpu maps and map-in-map in
sleepable programs"), sleepable BPF program can also use map-in-map, but
maybe_wait_bpf_programs() doesn't handle it accordingly. The main reason
is that using synchronize_rcu_tasks_trace() to wait for the completions
of these sleepable BPF programs may incur a very long delay and
userspace may think it is hung, so the wait for sleepable BPF programs
is skipped. Update the comments in maybe_wait_bpf_programs() to reflect
the reason.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20231211083447.1921178-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-13 17:01:42 -08:00
Matt Bobrowski
b13cddf633 bpf: add small subset of SECURITY_PATH hooks to BPF sleepable_lsm_hooks list
security_path_* based LSM hooks appear to be generally missing from
the sleepable_lsm_hooks list. Initially add a small subset of them to
the preexisting sleepable_lsm_hooks list so that sleepable BPF helpers
like bpf_d_path() can be used from sleepable BPF LSM based programs.

The security_path_* hooks added in this patch are similar to the
security_inode_* counterparts that already exist in the
sleepable_lsm_hooks list, and are called in roughly similar points and
contexts. Presumably, making them OK to be also annotated as
sleepable.

Building a kernel with DEBUG_ATOMIC_SLEEP options enabled and running
reasonable workloads stimulating activity that would be intercepted by
such security hooks didn't show any splats.

Notably, I haven't added all the security_path_* LSM hooks that are
available as I don't need them at this point in time.

Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/ZXM3IHHXpNY9y82a@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-13 16:56:19 -08:00
Andrii Nakryiko
f5fdb51fb9 bpf: fail BPF_TOKEN_CREATE if no delegation option was set on BPF FS
It's quite confusing in practice when it's possible to successfully
create a BPF token from BPF FS that didn't have any of delegate_xxx
mount options set up. While it's not wrong, it's actually more
meaningful to reject BPF_TOKEN_CREATE with specific error code (-ENOENT)
to let user-space know that no token delegation is setup up.

So, instead of creating empty BPF token that will be always ignored
because it doesn't have any of the allow_xxx bits set, reject it with
-ENOENT. If we ever need empty BPF token to be possible, we can support
that with extra flag passed into BPF_TOKEN_CREATE.

Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231213190842.3844987-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-13 15:47:04 -08:00
Jie Jiang
750e785796 bpf: Support uid and gid when mounting bpffs
Parse uid and gid in bpf_parse_param() so that they can be passed in as
the `data` parameter when mount() bpffs. This will be useful when we
want to control which user/group has the control to the mounted bpffs,
otherwise a separate chown() call will be needed.

Signed-off-by: Jie Jiang <jiejiang@chromium.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mike Frysinger <vapier@chromium.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231212093923.497838-1-jiejiang@chromium.org
2023-12-13 15:37:42 -08:00
Andrei Matei
745e031130 bpf: Comment on check_mem_size_reg
This patch adds a comment to check_mem_size_reg -- a function whose
meaning is not very transparent. The function implicitly deals with two
registers connected by convention, which is not obvious.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231210225149.67639-1-andreimatei1@gmail.com
2023-12-12 15:35:32 -08:00
Yang Li
56c26d5ad8 bpf: Remove unused backtrack_state helper functions
The function are defined in the verifier.c file, but not called
elsewhere, so delete the unused function.

kernel/bpf/verifier.c:3448:20: warning: unused function 'bt_set_slot'
kernel/bpf/verifier.c:3453:20: warning: unused function 'bt_clear_slot'
kernel/bpf/verifier.c:3488:20: warning: unused function 'bt_is_slot_set'

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20231212005436.103829-1-yang.lee@linux.alibaba.com

Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7714
2023-12-12 09:52:07 -08:00
Andrii Nakryiko
1a1ad782dc bpf: tidy up exception callback management a bit
Use the fact that we are passing subprog index around and have
a corresponding struct bpf_subprog_info in bpf_verifier_env for each
subprogram. We don't need to separately pass around a flag whether
subprog is exception callback or not, each relevant verifier function
can determine this using provided subprog index if we maintain
bpf_subprog_info properly.

Also move out exception callback-specific logic from
btf_prepare_func_args(), keeping it generic. We can enforce all these
restriction right before exception callback verification pass. We add
out parameter, arg_cnt, for now, but this will be unnecessary with
subsequent refactoring and will be removed.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231204233931.49758-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-11 19:23:32 -08:00
Andrii Nakryiko
22b769bb4f bpf: emit more dynptr information in verifier log
Emit dynptr type for CONST_PTR_TO_DYNPTR register. Also emit id,
ref_obj_id, and dynptr_id fields for STACK_DYNPTR stack slots.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231204233931.49758-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-11 19:21:22 -08:00
Andrii Nakryiko
1e68485d82 bpf: log PTR_TO_MEM memory size in verifier log
Emit valid memory size addressable through PTR_TO_MEM register.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231204233931.49758-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-11 19:21:22 -08:00
Linus Torvalds
3a87498869 - Make sure tasks are thawed exactly and only once to avoid their state
getting corrupted
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Merge tag 'sched_urgent_for_v6.7_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Borislav Petkov:

 - Make sure tasks are thawed exactly and only once to avoid their state
   getting corrupted

* tag 'sched_urgent_for_v6.7_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  freezer,sched: Do not restore saved_state of a thawed task
2023-12-10 11:09:16 -08:00
Linus Torvalds
537ccb5d28 - Make sure perf event size validation is done on every event in the
group
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Merge tag 'perf_urgent_for_v6.7_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf event fix from Borislav Petkov:

 - Make sure perf event size validation is done on every event in the
   group

* tag 'perf_urgent_for_v6.7_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix perf_event_validate_size()
2023-12-10 11:03:15 -08:00
David Vernet
a6de18f310 bpf: Add bpf_cpumask_weight() kfunc
It can be useful to query how many bits are set in a cpumask. For
example, if you want to perform special logic for the last remaining
core that's set in a mask. Let's therefore add a new
bpf_cpumask_weight() kfunc which checks how many bits are set in a mask.

Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20231207210843.168466-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 21:37:33 -08:00
Andrii Nakryiko
482d548d40 bpf: handle fake register spill to stack with BPF_ST_MEM instruction
When verifier validates BPF_ST_MEM instruction that stores known
constant to stack (e.g., *(u64 *)(r10 - 8) = 123), it effectively spills
a fake register with a constant (but initially imprecise) value to
a stack slot. Because read-side logic treats it as a proper register
fill from stack slot, we need to mark such stack slot initialization as
INSN_F_STACK_ACCESS instruction to stop precision backtracking from
missing it.

Fixes: 41f6f64e69 ("bpf: support non-r10 register spill/fill to/from stack in precision tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231209010958.66758-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 18:43:20 -08:00
Hou Tao
06e5c999f1 bpf: Set uattr->batch.count as zero before batched update or deletion
generic_map_{delete,update}_batch() doesn't set uattr->batch.count as
zero before it tries to allocate memory for key. If the memory
allocation fails, the value of uattr->batch.count will be incorrect.

Fix it by setting uattr->batch.count as zero beore batched update or
deletion.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231208102355.2628918-6-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 18:12:34 -08:00
Hou Tao
67ad2c73ff bpf: Only call maybe_wait_bpf_programs() when map operation succeeds
There is no need to call maybe_wait_bpf_programs() if update or deletion
operation fails. So only call maybe_wait_bpf_programs() if update or
deletion operation succeeds.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231208102355.2628918-5-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 18:12:34 -08:00
Hou Tao
012772581d bpf: Add missed maybe_wait_bpf_programs() for htab of maps
When doing batched lookup and deletion operations on htab of maps,
maybe_wait_bpf_programs() is needed to ensure all programs don't use the
inner map after the bpf syscall returns.

Instead of adding the wait in __htab_map_lookup_and_delete_batch(),
adding the wait in bpf_map_do_batch() and also removing the calling of
maybe_wait_bpf_programs() from generic_map_{delete,update}_batch().

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231208102355.2628918-4-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 18:12:34 -08:00
Hou Tao
37ba5b59d6 bpf: Call maybe_wait_bpf_programs() only once for generic_map_update_batch()
Just like commit 9087c6ff8d ("bpf: Call maybe_wait_bpf_programs() only
once from generic_map_delete_batch()"), there is also no need to call
maybe_wait_bpf_programs() for each update in batched update, so only
call it once in generic_map_update_batch().

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231208102355.2628918-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 18:12:33 -08:00
Hou Tao
c26f2a8901 bpf: Remove unnecessary wait from bpf_map_copy_value()
Both map_lookup_elem() and generic_map_lookup_batch() use
bpf_map_copy_value() to lookup and copy the value, and there is no
update operation in bpf_map_copy_value(), so just remove the invocation
of maybe_wait_bpf_programs() from it.

Fixes: 15c14a3dca ("bpf: Add bpf_map_{value_size, update_value, map_copy_value} functions")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231208102355.2628918-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-09 18:12:33 -08:00
Yafang Shao
73d9eb340d bpf: Enable bpf_cgrp_storage for cgroup1 non-attach case
In the current cgroup1 environment, associating operations between cgroups
and applications in a BPF program requires storing a mapping of cgroup_id
to application either in a hash map or maintaining it in userspace.
However, by enabling bpf_cgrp_storage for cgroup1, it becomes possible to
conveniently store application-specific information in cgroup-local storage
and utilize it within BPF programs. Furthermore, enabling this feature for
cgroup1 involves minor modifications for the non-attach case, streamlining
the process.

However, when it comes to enabling this functionality for the cgroup1
attach case, it presents challenges. Therefore, the decision is to focus on
enabling it solely for the cgroup1 non-attach case at present. If
attempting to attach to a cgroup1 fd, the operation will simply fail with
the error code -EBADF.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20231206115326.4295-2-laoar.shao@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-12-08 17:08:18 -08:00
Andrei Matei
2929bfac00 bpf: Minor cleanup around stack bounds
Push the rounding up of stack offsets into the function responsible for
growing the stack, rather than relying on all the callers to do it.
Uncertainty about whether the callers did it or not tripped up people in
a previous review.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20231208032519.260451-4-andreimatei1@gmail.com
2023-12-08 14:19:00 -08:00
Andrei Matei
6b4a64bafd bpf: Fix accesses to uninit stack slots
Privileged programs are supposed to be able to read uninitialized stack
memory (ever since 6715df8d5) but, before this patch, these accesses
were permitted inconsistently. In particular, accesses were permitted
above state->allocated_stack, but not below it. In other words, if the
stack was already "large enough", the access was permitted, but
otherwise the access was rejected instead of being allowed to "grow the
stack". This undesired rejection was happening in two places:
- in check_stack_slot_within_bounds()
- in check_stack_range_initialized()
This patch arranges for these accesses to be permitted. A bunch of tests
that were relying on the old rejection had to change; all of them were
changed to add also run unprivileged, in which case the old behavior
persists. One tests couldn't be updated - global_func16 - because it
can't run unprivileged for other reasons.

This patch also fixes the tracking of the stack size for variable-offset
reads. This second fix is bundled in the same commit as the first one
because they're inter-related. Before this patch, writes to the stack
using registers containing a variable offset (as opposed to registers
with fixed, known values) were not properly contributing to the
function's needed stack size. As a result, it was possible for a program
to verify, but then to attempt to read out-of-bounds data at runtime
because a too small stack had been allocated for it.

Each function tracks the size of the stack it needs in
bpf_subprog_info.stack_depth, which is maintained by
update_stack_depth(). For regular memory accesses, check_mem_access()
was calling update_state_depth() but it was passing in only the fixed
part of the offset register, ignoring the variable offset. This was
incorrect; the minimum possible value of that register should be used
instead.

This tracking is now fixed by centralizing the tracking of stack size in
grow_stack_state(), and by lifting the calls to grow_stack_state() to
check_stack_access_within_bounds() as suggested by Andrii. The code is
now simpler and more convincingly tracks the correct maximum stack size.
check_stack_range_initialized() can now rely on enough stack having been
allocated for the access; this helps with the fix for the first issue.

A few tests were changed to also check the stack depth computation. The
one that fails without this patch is verifier_var_off:stack_write_priv_vs_unpriv.

Fixes: 01f810ace9 ("bpf: Allow variable-offset stack access")
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231208032519.260451-3-andreimatei1@gmail.com

Closes: https://lore.kernel.org/bpf/CABWLsev9g8UP_c3a=1qbuZUi20tGoUXoU07FPf-5FLvhOKOY+Q@mail.gmail.com/
2023-12-08 14:19:00 -08:00
Linus Torvalds
17894c2a7a tracing fixes for v6.7-rc4:
- Snapshot buffer issues
 
   1. When instances started allowing latency tracers, it uses
      a snapshot buffer (another buffer that is not written to
      but swapped with the main buffer that is). The snapshot buffer
      needs to be the same size as the main buffer. But when the
      snapshot buffers were added to instances, the code to make
      the snapshot equal to the main buffer still was only doing it
      for the main buffer and not the instances.
 
   2. Need to stop the current tracer when resizing the buffers.
      Otherwise there can be a race if the tracer decides to make
      a snapshot between resizing the main buffer and the snapshot
      buffer.
 
   3. When a tracer is "stopped" in disables both the main buffer
      and the snapshot buffer. This needs to be done for instances
      and not only the main buffer, now that instances also have
      a snapshot buffer.
 
 - Buffered event for filtering issues
 
   When filtering is enabled, because events can be dropped often,
   it is quicker to copy the event into a temp buffer and write that
   into the main buffer if it is not filtered or just drop the event
   if it is, than to write the event into the ring buffer and then
   try to discard it. This temp buffer is allocated and needs special
   synchronization to do so. But there were some issues with that:
 
   1. When disabling the filter and freeing the buffer, a call to all
      CPUs is required to stop each per_cpu usage. But the code
      called smp_call_function_many() which does not include the
      current CPU. If the task is migrated to another CPU when it
      enables the CPUs via smp_call_function_many(), it will not enable
      the one it is currently on and this causes issues later on.
      Use on_each_cpu_mask() instead, which includes the current CPU.
 
    2. When the allocation of the buffered event fails, it can give
       a warning. But the buffered event is just an optimization
       (it's still OK to write to the ring buffer and free it).
       Do not WARN in this case.
 
    3. The freeing of the buffer event requires synchronization.
       First a counter is decremented to zero so that no new uses
       of it will happen. Then it sets the buffered event to NULL,
       and finally it frees the buffered event. There's a synchronize_rcu()
       between the counter decrement and the setting the variable to
       NULL, but only a smp_wmb() between that and the freeing of the
       buffer. It is theoretically possible that a user missed seeing
       the decrement, but will use the buffer after it is free. Another
       synchronize_rcu() is needed in place of that smp_wmb().
 
 - ring buffer timestamps on 32 bit machines
 
   The ring buffer timestamp on 32 bit machines has to break the 64 bit
   number into multiple values as cmpxchg is required on it, and a
   64 bit cmpxchg on 32 bit architectures is very slow. The code use
   to just use two 32 bit values and make it a 60 bit timestamp where
   the other 4 bits were used as counters for synchronization. It later
   came known that the timestamp on 32 bit still need all 64 bits in
   some cases. So 3 words were created to handle the 64 bits. But issues
   arised with this:
 
    1. The synchronization logic still only compared the counter
       with the first two, but not with the third number, so the
       synchronization could fail unknowingly.
 
    2. A check on discard of an event could race if an event happened
       between the discard and updating one of the counters. The
       counter needs to be updated (forcing an absolute timestamp
       and not to use a delta) before the actual discard happens.
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Merge tag 'trace-v6.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Snapshot buffer issues:

   1. When instances started allowing latency tracers, it uses a
      snapshot buffer (another buffer that is not written to but swapped
      with the main buffer that is). The snapshot buffer needs to be the
      same size as the main buffer. But when the snapshot buffers were
      added to instances, the code to make the snapshot equal to the
      main buffer still was only doing it for the main buffer and not
      the instances.

   2. Need to stop the current tracer when resizing the buffers.
      Otherwise there can be a race if the tracer decides to make a
      snapshot between resizing the main buffer and the snapshot buffer.

   3. When a tracer is "stopped" in disables both the main buffer and
      the snapshot buffer. This needs to be done for instances and not
      only the main buffer, now that instances also have a snapshot
      buffer.

 - Buffered event for filtering issues:

   When filtering is enabled, because events can be dropped often, it is
   quicker to copy the event into a temp buffer and write that into the
   main buffer if it is not filtered or just drop the event if it is,
   than to write the event into the ring buffer and then try to discard
   it. This temp buffer is allocated and needs special synchronization
   to do so. But there were some issues with that:

   1. When disabling the filter and freeing the buffer, a call to all
      CPUs is required to stop each per_cpu usage. But the code called
      smp_call_function_many() which does not include the current CPU.
      If the task is migrated to another CPU when it enables the CPUs
      via smp_call_function_many(), it will not enable the one it is
      currently on and this causes issues later on. Use
      on_each_cpu_mask() instead, which includes the current CPU.

    2.When the allocation of the buffered event fails, it can give a
      warning. But the buffered event is just an optimization (it's
      still OK to write to the ring buffer and free it). Do not WARN in
      this case.

    3.The freeing of the buffer event requires synchronization. First a
      counter is decremented to zero so that no new uses of it will
      happen. Then it sets the buffered event to NULL, and finally it
      frees the buffered event. There's a synchronize_rcu() between the
      counter decrement and the setting the variable to NULL, but only a
      smp_wmb() between that and the freeing of the buffer. It is
      theoretically possible that a user missed seeing the decrement,
      but will use the buffer after it is free. Another
      synchronize_rcu() is needed in place of that smp_wmb().

 - ring buffer timestamps on 32 bit machines

   The ring buffer timestamp on 32 bit machines has to break the 64 bit
   number into multiple values as cmpxchg is required on it, and a 64
   bit cmpxchg on 32 bit architectures is very slow. The code use to
   just use two 32 bit values and make it a 60 bit timestamp where the
   other 4 bits were used as counters for synchronization. It later came
   known that the timestamp on 32 bit still need all 64 bits in some
   cases. So 3 words were created to handle the 64 bits. But issues
   arised with this:

    1. The synchronization logic still only compared the counter with
       the first two, but not with the third number, so the
       synchronization could fail unknowingly.

    2. A check on discard of an event could race if an event happened
       between the discard and updating one of the counters. The counter
       needs to be updated (forcing an absolute timestamp and not to use
       a delta) before the actual discard happens.

* tag 'trace-v6.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Test last update in 32bit version of __rb_time_read()
  ring-buffer: Force absolute timestamp on discard of event
  tracing: Fix a possible race when disabling buffered events
  tracing: Fix a warning when allocating buffered events fails
  tracing: Fix incomplete locking when disabling buffered events
  tracing: Disable snapshot buffer when stopping instance tracers
  tracing: Stop current tracer when resizing buffer
  tracing: Always update snapshot buffer size
2023-12-08 08:44:43 -08:00
Linus Torvalds
8e819a7623 31 hotfixes. 10 of these address pre-6.6 issues and are marked cc:stable.
The remainder address post-6.6 issues or aren't considered serious enough
 to justify backporting.
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Merge tag 'mm-hotfixes-stable-2023-12-07-18-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "31 hotfixes. Ten of these address pre-6.6 issues and are marked
  cc:stable. The remainder address post-6.6 issues or aren't considered
  serious enough to justify backporting"

* tag 'mm-hotfixes-stable-2023-12-07-18-47' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (31 commits)
  mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range()
  nilfs2: prevent WARNING in nilfs_sufile_set_segment_usage()
  mm/hugetlb: have CONFIG_HUGETLB_PAGE select CONFIG_XARRAY_MULTI
  scripts/gdb: fix lx-device-list-bus and lx-device-list-class
  MAINTAINERS: drop Antti Palosaari
  highmem: fix a memory copy problem in memcpy_from_folio
  nilfs2: fix missing error check for sb_set_blocksize call
  kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP
  units: add missing header
  drivers/base/cpu: crash data showing should depends on KEXEC_CORE
  mm/damon/sysfs-schemes: add timeout for update_schemes_tried_regions
  scripts/gdb/tasks: fix lx-ps command error
  mm/Kconfig: make userfaultfd a menuconfig
  selftests/mm: prevent duplicate runs caused by TEST_GEN_PROGS
  mm/damon/core: copy nr_accesses when splitting region
  lib/group_cpus.c: avoid acquiring cpu hotplug lock in group_cpus_evenly
  checkstack: fix printed address
  mm/memory_hotplug: fix error handling in add_memory_resource()
  mm/memory_hotplug: add missing mem_hotplug_lock
  .mailmap: add a new address mapping for Chester Lin
  ...
2023-12-08 08:36:23 -08:00
Jakub Kicinski
2483e7f04c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR.

Conflicts:

drivers/net/ethernet/stmicro/stmmac/dwmac5.c
drivers/net/ethernet/stmicro/stmmac/dwmac5.h
drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
drivers/net/ethernet/stmicro/stmmac/hwif.h
  37e4b8df27 ("net: stmmac: fix FPE events losing")
  c3f3b97238 ("net: stmmac: Refactor EST implementation")
https://lore.kernel.org/all/20231206110306.01e91114@canb.auug.org.au/

Adjacent changes:

net/ipv4/tcp_ao.c
  9396c4ee93 ("net/tcp: Don't store TCP-AO maclen on reqsk")
  7b0f570f87 ("tcp: Move TCP-AO bits from cookie_v[46]_check() to tcp_ao_syncookie().")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-07 17:53:17 -08:00
Linus Torvalds
5e3f5b81de Including fixes from bpf and netfilter.
Current release - regressions:
 
  - veth: fix packet segmentation in veth_convert_skb_to_xdp_buff
 
 Current release - new code bugs:
 
  - tcp: assorted fixes to the new Auth Option support
 
 Older releases - regressions:
 
  - tcp: fix mid stream window clamp
 
  - tls: fix incorrect splice handling
 
  - ipv4: ip_gre: handle skb_pull() failure in ipgre_xmit()
 
  - dsa: mv88e6xxx: restore USXGMII support for 6393X
 
  - arcnet: restore support for multiple Sohard Arcnet cards
 
 Older releases - always broken:
 
  - tcp: do not accept ACK of bytes we never sent
 
  - require admin privileges to receive packet traces via netlink
 
  - packet: move reference count in packet_sock to atomic_long_t
 
  - bpf:
    - fix incorrect branch offset comparison with cpu=v4
    - fix prog_array_map_poke_run map poke update
 
  - netfilter:
    - 3 fixes for crashes on bad admin commands
    - xt_owner: fix race accessing sk->sk_socket, TOCTOU null-deref
    - nf_tables: fix 'exist' matching on bigendian arches
 
  - leds: netdev: fix RTNL handling to prevent potential deadlock
 
  - eth: tg3: prevent races in error/reset handling
 
  - eth: r8169: fix rtl8125b PAUSE storm when suspended
 
  - eth: r8152: improve reset and surprise removal handling
 
  - eth: hns: fix race between changing features and sending
 
  - eth: nfp: fix sleep in atomic for bonding offload
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-6.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Including fixes from bpf and netfilter.

  Current release - regressions:

   - veth: fix packet segmentation in veth_convert_skb_to_xdp_buff

  Current release - new code bugs:

   - tcp: assorted fixes to the new Auth Option support

  Older releases - regressions:

   - tcp: fix mid stream window clamp

   - tls: fix incorrect splice handling

   - ipv4: ip_gre: handle skb_pull() failure in ipgre_xmit()

   - dsa: mv88e6xxx: restore USXGMII support for 6393X

   - arcnet: restore support for multiple Sohard Arcnet cards

  Older releases - always broken:

   - tcp: do not accept ACK of bytes we never sent

   - require admin privileges to receive packet traces via netlink

   - packet: move reference count in packet_sock to atomic_long_t

   - bpf:
      - fix incorrect branch offset comparison with cpu=v4
      - fix prog_array_map_poke_run map poke update

   - netfilter:
      - three fixes for crashes on bad admin commands
      - xt_owner: fix race accessing sk->sk_socket, TOCTOU null-deref
      - nf_tables: fix 'exist' matching on bigendian arches

   - leds: netdev: fix RTNL handling to prevent potential deadlock

   - eth: tg3: prevent races in error/reset handling

   - eth: r8169: fix rtl8125b PAUSE storm when suspended

   - eth: r8152: improve reset and surprise removal handling

   - eth: hns: fix race between changing features and sending

   - eth: nfp: fix sleep in atomic for bonding offload"

* tag 'net-6.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (62 commits)
  vsock/virtio: fix "comparison of distinct pointer types lacks a cast" warning
  net/smc: fix missing byte order conversion in CLC handshake
  net: dsa: microchip: provide a list of valid protocols for xmit handler
  drop_monitor: Require 'CAP_SYS_ADMIN' when joining "events" group
  psample: Require 'CAP_NET_ADMIN' when joining "packets" group
  bpf: sockmap, updating the sg structure should also update curr
  net: tls, update curr on splice as well
  nfp: flower: fix for take a mutex lock in soft irq context and rcu lock
  net: dsa: mv88e6xxx: Restore USXGMII support for 6393X
  tcp: do not accept ACK of bytes we never sent
  selftests/bpf: Add test for early update in prog_array_map_poke_run
  bpf: Fix prog_array_map_poke_run map poke update
  netfilter: xt_owner: Fix for unsafe access of sk->sk_socket
  netfilter: nf_tables: validate family when identifying table via handle
  netfilter: nf_tables: bail out on mismatching dynset and set expressions
  netfilter: nf_tables: fix 'exist' matching on bigendian arches
  netfilter: nft_set_pipapo: skip inactive elements during set walk
  netfilter: bpf: fix bad registration on nf_defrag
  leds: trigger: netdev: fix RTNL handling to prevent potential deadlock
  octeontx2-af: Update Tx link register range
  ...
2023-12-07 17:04:13 -08:00
Andrei Matei
1d38a9ee81 bpf: Guard stack limits against 32bit overflow
This patch promotes the arithmetic around checking stack bounds to be
done in the 64-bit domain, instead of the current 32bit. The arithmetic
implies adding together a 64-bit register with a int offset. The
register was checked to be below 1<<29 when it was variable, but not
when it was fixed. The offset either comes from an instruction (in which
case it is 16 bit), from another register (in which case the caller
checked it to be below 1<<29 [1]), or from the size of an argument to a
kfunc (in which case it can be a u32 [2]). Between the register being
inconsistently checked to be below 1<<29, and the offset being up to an
u32, it appears that we were open to overflowing the `int`s which were
currently used for arithmetic.

[1] 815fb87b75/kernel/bpf/verifier.c (L7494-L7498)
[2] 815fb87b75/kernel/bpf/verifier.c (L11904)

Reported-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231207041150.229139-4-andreimatei1@gmail.com
2023-12-07 13:58:10 -08:00
Andrei Matei
a833a17aea bpf: Fix verification of indirect var-off stack access
This patch fixes a bug around the verification of possibly-zero-sized
stack accesses. When the access was done through a var-offset stack
pointer, check_stack_access_within_bounds was incorrectly computing the
maximum-offset of a zero-sized read to be the same as the register's min
offset. Instead, we have to take in account the register's maximum
possible value. The patch also simplifies how the max offset is checked;
the check is now simpler than for min offset.

The bug was allowing accesses to erroneously pass the
check_stack_access_within_bounds() checks, only to later crash in
check_stack_range_initialized() when all the possibly-affected stack
slots are iterated (this time with a correct max offset).
check_stack_range_initialized() is relying on
check_stack_access_within_bounds() for its accesses to the
stack-tracking vector to be within bounds; in the case of zero-sized
accesses, we were essentially only verifying that the lowest possible
slot was within bounds. We would crash when the max-offset of the stack
pointer was >= 0 (which shouldn't pass verification, and hopefully is
not something anyone's code attempts to do in practice).

Thanks Hao for reporting!

Fixes: 01f810ace9 ("bpf: Allow variable-offset stack access")
Reported-by: Hao Sun <sunhao.th@gmail.com>
Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231207041150.229139-2-andreimatei1@gmail.com

Closes: https://lore.kernel.org/bpf/CACkBjsZGEUaRCHsmaX=h-efVogsRfK1FPxmkgb0Os_frnHiNdw@mail.gmail.com/
2023-12-07 13:57:53 -08:00
Linus Torvalds
9ace34a8e4 cgroup: Fixes for v6.7-rc4
Just one patch.
 
 f5d39b0208 ("freezer,sched: Rewrite core freezer logic") changed how
 freezing state is recorded which cgroup_freezing() disagree with the actual
 state of the task while thawing triggering a warning. Fix it by updating
 cgroup_freezing().
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Merge tag 'cgroup-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fix from Tejun Heo:
 "Just one fix.

  Commit f5d39b0208 ("freezer,sched: Rewrite core freezer logic")
  changed how freezing state is recorded which made cgroup_freezing()
  disagree with the actual state of the task while thawing triggering a
  warning. Fix it by updating cgroup_freezing()"

* tag 'cgroup-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup_freezer: cgroup_freezing: Check if not frozen
2023-12-07 12:42:40 -08:00
Linus Torvalds
e0348c1f68 workqueue: Fixes for v6.7-rc4
Just one patch to fix a bug which can crash the kernel if the housekeeping
 and wq_unbound_cpu cpumask configuration combination leaves the latter
 empty.
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Merge tag 'wq-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue fix from Tejun Heo:
 "Just one patch to fix a bug which can crash the kernel if the
  housekeeping and wq_unbound_cpu cpumask configuration combination
  leaves the latter empty"

* tag 'wq-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Make sure that wq_unbound_cpumask is never empty
2023-12-07 12:36:32 -08:00
Song Liu
26ef208c20 bpf: Use arch_bpf_trampoline_size
Instead of blindly allocating PAGE_SIZE for each trampoline, check the size
of the trampoline with arch_bpf_trampoline_size(). This size is saved in
bpf_tramp_image->size, and used for modmem charge/uncharge. The fallback
arch_alloc_bpf_trampoline() still allocates a whole page because we need to
use set_memory_* to protect the memory.

struct_ops trampoline still uses a whole page for multiple trampolines.

With this size check at caller (regular trampoline and struct_ops
trampoline), remove arch_bpf_trampoline_size() from
arch_prepare_bpf_trampoline() in archs.

Also, update bpf_image_ksym_add() to handle symbol of different sizes.

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>  # on s390x
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com> # on riscv
Link: https://lore.kernel.org/r/20231206224054.492250-7-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-06 17:17:20 -08:00
Song Liu
96d1b7c081 bpf: Add arch_bpf_trampoline_size()
This helper will be used to calculate the size of the trampoline before
allocating the memory.

arch_prepare_bpf_trampoline() for arm64 and riscv64 can use
arch_bpf_trampoline_size() to check the trampoline fits in the image.

OTOH, arch_prepare_bpf_trampoline() for s390 has to call the JIT process
twice, so it cannot use arch_bpf_trampoline_size().

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>  # on s390x
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Björn Töpel <bjorn@rivosinc.com> # on riscv
Link: https://lore.kernel.org/r/20231206224054.492250-6-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-06 17:17:20 -08:00
Song Liu
82583daa2e bpf: Add helpers for trampoline image management
As BPF trampoline of different archs moves from bpf_jit_[alloc|free]_exec()
to bpf_prog_pack_[alloc|free](), we need to use different _alloc, _free for
different archs during the transition. Add the following helpers for this
transition:

void *arch_alloc_bpf_trampoline(unsigned int size);
void arch_free_bpf_trampoline(void *image, unsigned int size);
void arch_protect_bpf_trampoline(void *image, unsigned int size);
void arch_unprotect_bpf_trampoline(void *image, unsigned int size);

The fallback version of these helpers require size <= PAGE_SIZE, but they
are only called with size == PAGE_SIZE. They will be called with size <
PAGE_SIZE when arch_bpf_trampoline_size() helper is introduced later.

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>  # on s390x
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20231206224054.492250-4-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-06 17:17:20 -08:00
Song Liu
7a3d9a159b bpf: Adjust argument names of arch_prepare_bpf_trampoline()
We are using "im" for "struct bpf_tramp_image" and "tr" for "struct
bpf_trampoline" in most of the code base. The only exception is the
prototype and fallback version of arch_prepare_bpf_trampoline(). Update
them to match the rest of the code base.

We mix "orig_call" and "func_addr" for the argument in different versions
of arch_prepare_bpf_trampoline(). s/orig_call/func_addr/g so they match.

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>  # on s390x
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20231206224054.492250-3-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-06 17:17:20 -08:00
Song Liu
f08a1c6582 bpf: Let bpf_prog_pack_free handle any pointer
Currently, bpf_prog_pack_free only can only free pointer to struct
bpf_binary_header, which is not flexible. Add a size argument to
bpf_prog_pack_free so that it can handle any pointer.

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>  # on s390x
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20231206224054.492250-2-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-06 17:17:20 -08:00
Baoquan He
dccf78d39f kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP
Ignat Korchagin complained that a potential config regression was
introduced by commit 89cde45591 ("kexec: consolidate kexec and crash
options into kernel/Kconfig.kexec").  Before the commit, CONFIG_CRASH_DUMP
has no dependency on CONFIG_KEXEC.  After the commit, CRASH_DUMP selects
KEXEC.  That enforces system to have CONFIG_KEXEC=y as long as
CONFIG_CRASH_DUMP=Y which people may not want.

In Ignat's case, he sets CONFIG_CRASH_DUMP=y, CONFIG_KEXEC_FILE=y and
CONFIG_KEXEC=n because kexec_load interface could have security issue if
kernel/initrd has no chance to be signed and verified.

CRASH_DUMP has select of KEXEC because Eric, author of above commit, met a
LKP report of build failure when posting patch of earlier version.  Please
see below link to get detail of the LKP report:

    https://lore.kernel.org/all/3e8eecd1-a277-2cfb-690e-5de2eb7b988e@oracle.com/T/#u

In fact, that LKP report is triggered because arm's <asm/kexec.h> is
wrapped in CONFIG_KEXEC ifdeffery scope.  That is wrong.  CONFIG_KEXEC
controls the enabling/disabling of kexec_load interface, but not kexec
feature.  Removing the wrongly added CONFIG_KEXEC ifdeffery scope in
<asm/kexec.h> of arm allows us to drop the select KEXEC for CRASH_DUMP. 
Meanwhile, change arch/arm/kernel/Makefile to let machine_kexec.o
relocate_kernel.o depend on KEXEC_CORE.

Link: https://lkml.kernel.org/r/20231128054457.659452-1-bhe@redhat.com
Fixes: 89cde45591 ("kexec: consolidate kexec and crash options into kernel/Kconfig.kexec")
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Ignat Korchagin <ignat@cloudflare.com>
Tested-by: Ignat Korchagin <ignat@cloudflare.com>	[compile-time only]
Tested-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Tested-by: Eric DeVolder <eric_devolder@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-06 16:12:48 -08:00