Re: [PATCH 5.14 000/173] 5.14.10-rc2 review

[Naresh Kamboju <naresh.kamboju@linaro.org>]

On Wed, 6 Oct 2021 at 00:37, Thomas Backlund <tmb@iki.fi> wrote:
>
> Den 2021-10-05 kl. 18:59, skrev Guenter Roeck:
> > On Tue, Oct 05, 2021 at 10:38:40AM +0200, Greg Kroah-Hartman wrote:
> >> This is the start of the stable review cycle for the 5.14.10 release.
> >> There are 173 patches in this series, all will be posted as a response
> >> to this one.  If anyone has any issues with these being applied, please
> >> let me know.
> >>
> >> Responses should be made by Thu, 07 Oct 2021 08:32:44 +0000.
> >> Anything received after that time might be too late.
> >>
> >
> > AFAICS the warning problems are still seen. Unfortunately I won't be able
> > to bisect since I have limited internet access.
> >
> > Guenter
> >
> > =========================
> > WARNING: held lock freed!
> > 5.14.10-rc2-00174-g355f3195d051 #1 Not tainted
> > -------------------------
> > ip/202 is freeing memory c000000009918900-c000000009918f7f, with a lock still held there!
> > c000000009918a20 (sk_lock-AF_INET){+.+.}-{0:0}, at: .sk_common_release+0x4c/0x1b0
> > 2 locks held by ip/202:
> >   #0: c00000000ae149d0 (&sb->s_type->i_mutex_key#5){+.+.}-{3:3}, at: .__sock_release+0x4c/0x150
> >   #1: c000000009918a20 (sk_lock-AF_INET){+.+.}-{0:0}, at: .sk_common_release+0x4c/0x1b0
> >
> >
>

When I reverted the following two patches the warning got fixed.

73a03563f123 af_unix: fix races in sk_peer_pid and sk_peer_cred accesses
b226d61807f1 net: introduce and use lock_sock_fast_nested()


> Isn't this a fallout of:
>
> queue-5.14/net-introduce-and-use-lock_sock_fast_nested.patch
> that has: Fixes: 2dcb96bacce3 ("net: core: Correct the
> sock::sk_lock.owned lockdep annotations")

I have cherry-picked and tested but still I see this  new warning.

old warings are:
----------------------
[ 22.528947] WARNING: held lock freed!
or
[ 36.765439] WARNING: lock held when returning to user space!


new warning after the cherry pick.
------------------
[   22.330646] ============================================
[   22.335955] WARNING: possible recursive locking detected
[   22.341260] 5.14.10-rc2 #1 Not tainted
[   22.345004] --------------------------------------------
[   22.348869] igb 0000:02:00.0 eno2: renamed from eth1
[   22.350309] sd-resolve/345 is trying to acquire lock:
[   22.350310] ffff9a39c9580120 (sk_lock-AF_INET){+.+.}-{0:0}, at:
udp_destroy_sock+0x3a/0xe0
[   22.350317]
[   22.350317] but task is already holding lock:
[   22.350317] ffff9a39c9580120 (sk_lock-AF_INET){+.+.}-{0:0}, at:
sk_common_release+0x22/0x110
[   22.350321]
[   22.350321] other info that might help us debug this:
[   22.350321]  Possible unsafe locking scenario:
[   22.350321]
[   22.350322]        CPU0
[   22.350322]        ----
[   22.350322]   lock(sk_lock-AF_INET);
[   22.350323]   lock(sk_lock-AF_INET);
[   22.350324]
[   22.350324]  *** DEADLOCK ***
[   22.350324]
[   22.350324]  May be due to missing lock nesting notation
[   22.350324]
[   22.350325] 2 locks held by sd-resolve/345:
[   22.350326]  #0: ffff9a39c0610c10
(&sb->s_type->i_mutex_key#6){+.+.}-{3:3}, at: __sock_release+0x32/0xb0
[   22.424188]  #1: ffff9a39c9580120 (sk_lock-AF_INET){+.+.}-{0:0},
at: sk_common_release+0x22/0x110
[   22.424191]
[   22.424191] stack backtrace:
[   22.424192] CPU: 2 PID: 345 Comm: sd-resolve Not tainted 5.14.10-rc2 #1
[   22.424194] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[   22.424195] Call Trace:
[   22.424196]  dump_stack_lvl+0x49/0x5e
[   22.424200]  dump_stack+0x10/0x12
[   22.424202]  __lock_acquire.cold+0x21f/0x2b8
[   22.424204]  ? lock_is_held_type+0x9d/0x110
[   22.424207]  lock_acquire+0xb5/0x2c0
[   22.424209]  ? udp_destroy_sock+0x3a/0xe0
[   22.424212]  ? sk_common_release+0x22/0x110
[   22.424214]  __lock_sock_fast+0x34/0x90
[   22.424216]  ? udp_destroy_sock+0x3a/0xe0
[   22.424217]  udp_destroy_sock+0x3a/0xe0
[   22.424219]  ? sk_common_release+0x22/0x110
[   22.424220]  sk_common_release+0x22/0x110
[   22.424221]  udp_lib_close+0x9/0x10
[   22.424223]  inet_release+0x48/0x80
[   22.424225]  __sock_release+0x42/0xb0
[   22.424227]  sock_close+0x18/0x20
[   22.424228]  __fput+0xbb/0x270
[   22.424230]  ____fput+0xe/0x10
[   22.424231]  task_work_run+0x64/0xb0
[   22.424234]  exit_to_user_mode_prepare+0x201/0x210
[   22.424237]  syscall_exit_to_user_mode+0x1e/0x50
[   22.424239]  do_syscall_64+0x69/0x80
[   22.424241]  ? do_syscall_64+0x69/0x80
[   22.424243]  ? exc_page_fault+0x7c/0x220
[   22.424244]  ? asm_exc_page_fault+0x8/0x30
[   22.424246]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   22.424248] RIP: 0033:0x7f509b8c4837
[   22.424250] Code: 2c 00 f7 d8 64 89 02 b8 ff ff ff ff c3 48 8b 0d
57 86 2c 00 f7 d8 64 89 01 b8 ff ff ff ff eb c2 0f 1f 00 b8 03 00 00
00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 31 86 2c 00 f7 d8 64 89
02 b8
[   22.424251] RSP: 002b:00007f509a9419c8 EFLAGS: 00000213 ORIG_RAX:
0000000000000003
[   22.424253] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00007f509b8c4837
[   22.424254] RDX: 0000000000001387 RSI: 0000000000000000 RDI: 000000000000000c
[   22.424255] RBP: 00007f509a949db8 R08: 0000000000000000 R09: 0000000000005d18
[   22.424256] R10: 00007ffc8831c080 R11: 0000000000000213 R12: 0000000000000000
[   22.424257] R13: 0000000000000000 R14: 00007f509a949db8 R15: 0000000000000004

ref:
new warning after the cherry-pick full test log link,
https://lkft.validation.linaro.org/scheduler/job/3673750


on RC2 the original reported warning links,
https://lkft.validation.linaro.org/scheduler/job/3672925#L1185
https://lkft.validation.linaro.org/scheduler/job/3672930#L1261


>
> BUT:
>
> $ git describe --contains 2dcb96bacce3
> v5.15-rc3~30^2~26
>
> --
> Thomas

- Naresh