Re: [PATCH bpf-next v6 1/2] bpf: Fix a race condition between btf_put() and map_free()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@xxxxxxxxxx>:

On Thu, 14 Dec 2023 12:38:15 -0800 you wrote:
> 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
> 
> [...]

Here is the summary with links:
  - [bpf-next,v6,1/2] bpf: Fix a race condition between btf_put() and map_free()
    https://git.kernel.org/bpf/bpf-next/c/59e5791f59dd
  - [bpf-next,v6,2/2] selftests/bpf: Remove flaky test_btf_id test
    https://git.kernel.org/bpf/bpf-next/c/56925f389e15

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html






[Index of Archives]     [Linux Samsung SoC]     [Linux Rockchip SoC]     [Linux Actions SoC]     [Linux for Synopsys ARC Processors]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]


  Powered by Linux