BUG: sleeping function called from invalid context in lock_sock_nested

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 63de3747 Merge tag 'tag-chrome-platform-for-v5.5' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1727d59ce00000
kernel config: https://syzkaller.appspot.com/x/.config?x=1d189d07c6717979
dashboard link: https://syzkaller.appspot.com/bug?extid=c2f1558d49e25cc36e5e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fcf97ee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c2f155...@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at net/core/sock.c:2935
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 9008, name: udevd
4 locks held by udevd/9008:
#0: ffff888098598428 (sb_writers#5){.+.+}, at: sb_start_write
include/linux/fs.h:1650 [inline]
#0: ffff888098598428 (sb_writers#5){.+.+}, at: mnt_want_write+0x3f/0xc0
fs/namespace.c:354
#1: ffff8880a02bb248 (&type->i_mutex_dir_key#4/1){+.+.}, at:
inode_lock_nested include/linux/fs.h:826 [inline]
#1: ffff8880a02bb248 (&type->i_mutex_dir_key#4/1){+.+.}, at:
filename_create+0x17c/0x4f0 fs/namei.c:3630
#2: ffffffff89bb27a8 (tomoyo_ss){....}, at: tomoyo_path_perm+0x1cb/0x430
security/tomoyo/file.c:847
#3: ffffffff897a3fc0 (rcu_callback){....}, at: __rcu_reclaim
kernel/rcu/rcu.h:210 [inline]
#3: ffffffff897a3fc0 (rcu_callback){....}, at: rcu_do_batch
kernel/rcu/tree.c:2183 [inline]
#3: ffffffff897a3fc0 (rcu_callback){....}, at: rcu_core+0x5f8/0x1540
kernel/rcu/tree.c:2408
Preemption disabled at:
[<ffffffff880000f3>] __do_softirq+0xf3/0x98c kernel/softirq.c:269
CPU: 1 PID: 9008 Comm: udevd Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800
__might_sleep+0x95/0x190 kernel/sched/core.c:6753
lock_sock_nested+0x39/0x120 net/core/sock.c:2935
lock_sock include/net/sock.h:1526 [inline]
af_alg_release_parent+0x1a6/0x290 crypto/af_alg.c:137
hash_sock_destruct+0x164/0x1c0 crypto/algif_hash.c:423
__sk_destruct+0x53/0x7f0 net/core/sock.c:1695
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2183 [inline]
rcu_core+0x570/0x1540 kernel/rcu/tree.c:2408
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2417
__do_softirq+0x262/0x98c kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
</IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:70 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:102
Code: ff cc cc cc cc cc cc cc cc cc 55 48 89 e5 65 48 8b 04 25 c0 1e 02 00
65 8b 15 34 23 8d 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b <8b> 90 80 13 00
00 83 fa 02 75 20 48 8b 88 88 13 00 00 8b 80 84 13
RSP: 0018:ffffc90001d67a58 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88809ac86680 RBX: 0000000000000011 RCX: ffffffff835559d0
RDX: 0000000000000000 RSI: ffffffff8355597e RDI: 0000000000000003
RBP: ffffc90001d67a58 R08: ffff88809ac86680 R09: ffffed1014154557
R10: ffffed1014154556 R11: ffff8880a0aa2ab7 R12: dffffc0000000000
R13: ffff8880a0aa2ab0 R14: ffffc90001d67ba0 R15: 0000000000000011
tomoyo_check_acl+0x28e/0x3e0 security/tomoyo/domain.c:181
tomoyo_path_permission security/tomoyo/file.c:586 [inline]
tomoyo_path_permission+0x1fb/0x360 security/tomoyo/file.c:573
tomoyo_path_perm+0x374/0x430 security/tomoyo/file.c:838
tomoyo_path_symlink+0xaa/0xf0 security/tomoyo/tomoyo.c:206
security_path_symlink+0x10a/0x170 security/security.c:1053
do_symlinkat+0x137/0x290 fs/namei.c:4148
__do_sys_symlink fs/namei.c:4169 [inline]
__se_sys_symlink fs/namei.c:4167 [inline]
__x64_sys_symlink+0x59/0x80 fs/namei.c:4167
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f68d8603517
Code: 09 01 00 00 0f 05 48 3d 00 f0 ff ff 77 02 f3 c3 48 8b 15 14 39 2b 00
f7 d8 64 89 02 83 c8 ff c3 90 90 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 01 c3 48 8b 0d f1 38 2b 00 31 d2 48 29 c2 64
RSP: 002b:00007ffc322deae8 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00000000025b6250 RCX: 00007f68d8603517
RDX: 0000000000000002 RSI: 00007ffc322deb10 RDI: 00000000025cf730
RBP: 00000000025b62d0 R08: 00007ffc322de6c0 R09: 00007f68d8657de0
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000032
R13: 00000000025c7970 R14: 00000000025b6250 R15: 000000000000000b

================================
WARNING: inconsistent lock state
5.4.0-syzkaller #0 Tainted: G W
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
udevd/9008 [HC0[0]:SC1[3]:HE1:SE0] takes:
ffff88809f5a9110 (sk_lock-AF_ALG){+.?.}, at: lock_sock
include/net/sock.h:1526 [inline]
ffff88809f5a9110 (sk_lock-AF_ALG){+.?.}, at:
af_alg_release_parent+0x1a6/0x290 crypto/af_alg.c:137
{SOFTIRQ-ON-W} state was registered at:
__trace_hardirqs_on_caller kernel/locking/lockdep.c:3389 [inline]
lockdep_hardirqs_on+0x421/0x5e0 kernel/locking/lockdep.c:3434
trace_hardirqs_on+0x67/0x240 kernel/trace/trace_preemptirq.c:31
__local_bh_enable_ip+0x15a/0x270 kernel/softirq.c:194
local_bh_enable include/linux/bottom_half.h:32 [inline]
lock_sock_nested+0xe2/0x120 net/core/sock.c:2945
lock_sock include/net/sock.h:1526 [inline]
alg_bind+0x288/0x570 crypto/af_alg.c:187
__sys_bind+0x239/0x290 net/socket.c:1649
__do_sys_bind net/socket.c:1660 [inline]
__se_sys_bind net/socket.c:1658 [inline]
__x64_sys_bind+0x73/0xb0 net/socket.c:1658
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
irq event stamp: 55316
hardirqs last enabled at (55316): [<ffffffff81006743>]
trace_hardirqs_on_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:41
hardirqs last disabled at (55315): [<ffffffff8100675f>]
trace_hardirqs_off_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:42
softirqs last enabled at (53682): [<ffffffff812aa92e>] memcpy
include/linux/string.h:380 [inline]
softirqs last enabled at (53682): [<ffffffff812aa92e>]
fpu__copy+0x17e/0x8c0 arch/x86/kernel/fpu/core.c:195
softirqs last disabled at (55075): [<ffffffff81475c8b>] invoke_softirq
kernel/softirq.c:373 [inline]
softirqs last disabled at (55075): [<ffffffff81475c8b>]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(sk_lock-AF_ALG);
<Interrupt>
lock(sk_lock-AF_ALG);

*** DEADLOCK ***

4 locks held by udevd/9008:
#0: ffff888098598428 (sb_writers#5){.+.+}, at: sb_start_write
include/linux/fs.h:1650 [inline]
#0: ffff888098598428 (sb_writers#5){.+.+}, at: mnt_want_write+0x3f/0xc0
fs/namespace.c:354
#1: ffff8880a02bb248 (&type->i_mutex_dir_key#4/1){+.+.}, at:
inode_lock_nested include/linux/fs.h:826 [inline]
#1: ffff8880a02bb248 (&type->i_mutex_dir_key#4/1){+.+.}, at:
filename_create+0x17c/0x4f0 fs/namei.c:3630
#2: ffffffff89bb27a8 (tomoyo_ss){....}, at: tomoyo_path_perm+0x1cb/0x430
security/tomoyo/file.c:847
#3: ffffffff897a3fc0 (rcu_callback){....}, at: __rcu_reclaim
kernel/rcu/rcu.h:210 [inline]
#3: ffffffff897a3fc0 (rcu_callback){....}, at: rcu_do_batch
kernel/rcu/tree.c:2183 [inline]
#3: ffffffff897a3fc0 (rcu_callback){....}, at: rcu_core+0x5f8/0x1540
kernel/rcu/tree.c:2408

stack backtrace:
CPU: 1 PID: 9008 Comm: udevd Tainted: G W 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
print_usage_bug.cold+0x327/0x378 kernel/locking/lockdep.c:3101
valid_state kernel/locking/lockdep.c:3112 [inline]
mark_lock_irq kernel/locking/lockdep.c:3309 [inline]
mark_lock+0xbb4/0x1220 kernel/locking/lockdep.c:3666
mark_usage kernel/locking/lockdep.c:3566 [inline]
__lock_acquire+0x1e8e/0x4a00 kernel/locking/lockdep.c:3909
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
lock_sock_nested+0xcb/0x120 net/core/sock.c:2944
lock_sock include/net/sock.h:1526 [inline]
af_alg_release_parent+0x1a6/0x290 crypto/af_alg.c:137
hash_sock_destruct+0x164/0x1c0 crypto/algif_hash.c:423
__sk_destruct+0x53/0x7f0 net/core/sock.c:1695
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2183 [inline]
rcu_core+0x570/0x1540 kernel/rcu/tree.c:2408
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2417
__do_softirq+0x262/0x98c kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
</IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:70 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:102
Code: ff cc cc cc cc cc cc cc cc cc 55 48 89 e5 65 48 8b 04 25 c0 1e 02 00
65 8b 15 34 23 8d 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b <8b> 90 80 13 00
00 83 fa 02 75 20 48 8b 88 88 13 00 00 8b 80 84 13
RSP: 0018:ffffc90001d67a58 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88809ac86680 RBX: 0000000000000011 RCX: ffffffff835559d0
RDX: 0000000000000000 RSI: ffffffff8355597e RDI: 0000000000000003
RBP: ffffc90001d67a58 R08: ffff88809ac86680 R09: ffffed1014154557
R10: ffffed1014154556 R11: ffff8880a0aa2ab7 R12: dffffc0000000000
R13: ffff8880a0aa2ab0 R14: ffffc90001d67ba0 R15: 0000000000000011
tomoyo_check_acl+0x28e/0x3e0 security/tomoyo/domain.c:181
tomoyo_path_permission security/tomoyo/file.c:586 [inline]
tomoyo_path_permission+0x1fb/0x360 security/tomoyo/file.c:573
tomoyo_path_perm+0x374/0x430 security/tomoyo/file.c:838
tomoyo_path_symlink+0xaa/0xf0 security/tomoyo/tomoyo.c:206
security_path_symlink+0x10a/0x170 security/security.c:1053
do_symlinkat+0x137/0x290 fs/namei.c:4148
__do_sys_symlink fs/namei.c:4169 [inline]
__se_sys_symlink fs/namei.c:4167 [inline]
__x64_sys_symlink+0x59/0x80 fs/namei.c:4167
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f68d8603517
Code: 09 01 00 00 0f 05 48 3d 00 f0 ff ff 77 02 f3 c3 48 8b 15 14 39 2b 00
f7 d8 64 89 02 83 c8 ff c3 90 90 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff
ff 73 01 c3 48 8b 0d f1 38 2b 00 31 d2 48 29 c2 64
RSP: 002b:00007ffc322deae8 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00000000025b6250 RCX: 00007f68d8603517
RDX: 0000000000000002 RSI: 00007ffc322deb10 RDI: 00000000025cf730
RBP: 00000000025b62d0 R08: 00007ffc322de6c0 R09: 00007f68d8657de0
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000032
R13: 00000000025c7970 R14: 00000000025b6250 R15: 000000000000000b
BUG: sleeping function called from invalid context at net/core/sock.c:2935
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 16, name: ksoftirqd/1
INFO: lockdep is turned off.
Preemption disabled at:
[<ffffffff880000f3>] __do_softirq+0xf3/0x98c kernel/softirq.c:269
CPU: 1 PID: 16 Comm: ksoftirqd/1 Tainted: G W
5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800
__might_sleep+0x95/0x190 kernel/sched/core.c:6753
lock_sock_nested+0x39/0x120 net/core/sock.c:2935
lock_sock include/net/sock.h:1526 [inline]
af_alg_release_parent+0x1a6/0x290 crypto/af_alg.c:137
hash_sock_destruct+0x164/0x1c0 crypto/algif_hash.c:423
__sk_destruct+0x53/0x7f0 net/core/sock.c:1695
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2183 [inline]
rcu_core+0x570/0x1540 kernel/rcu/tree.c:2408
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2417
__do_softirq+0x262/0x98c kernel/softirq.c:292
run_ksoftirqd kernel/softirq.c:603 [inline]
run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
BUG: sleeping function called from invalid context at net/core/sock.c:2935
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 16, name: ksoftirqd/1
INFO: lockdep is turned off.
Preemption disabled at:
[<ffffffff880000f3>] __do_softirq+0xf3/0x98c kernel/softirq.c:269
CPU: 1 PID: 16 Comm: ksoftirqd/1 Tainted: G W
5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800
__might_sleep+0x95/0x190 kernel/sched/core.c:6753
lock_sock_nested+0x39/0x120 net/core/sock.c:2935
lock_sock include/net/sock.h:1526 [inline]
af_alg_release_parent+0x1a6/0x290 crypto/af_alg.c:137
hash_sock_destruct+0x164/0x1c0 crypto/algif_hash.c:423
__sk_destruct+0x53/0x7f0 net/core/sock.c:1695
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2183 [inline]
rcu_core+0x570/0x1540 kernel/rcu/tree.c:2408
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2417
__do_softirq+0x262/0x98c kernel/softirq.c:292
run_ksoftirqd kernel/softirq.c:603 [inline]
run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Eric Dumazet]

crypto layer (hash_sock_destruct()) is called from rcu callback (this in BH context) but tries to grab a socket lock.

A socket lock can schedule, which is illegal in BH context.

[Herbert Xu]

On Wed, Dec 04, 2019 at 08:59:11PM -0800, Eric Dumazet wrote:
>
> crypto layer (hash_sock_destruct()) is called from rcu callback (this in BH context) but tries to grab a socket lock.
>
> A socket lock can schedule, which is illegal in BH context.

Fair enough. Although I was rather intrigued as to how the RCU call
occured in the first place. After some digging my theory is that
this is due to a SO_ATTACH_REUSEPORT_CBPF or SO_ATTACH_REUSEPORT_EBPF
setsockopt on the crypto socket.

What are these filters even suppposed to do on an af_alg socket?

Anyhow, this is a bug that could have been triggered even without
this, but it would have been almost impossible to do it through
syzbot as you need to have an outstanding async skcipher/aead request
that is freed in BH context.

---8<---
As af_alg_release_parent may be called from BH context (most notably
due to an async request that only completes after socket closure,
or as reported here because of an RCU-delayed sk_destruct call), we
must use bh_lock_sock instead of lock_sock.

Reported-by: syzbot+c2f155...@syzkaller.appspotmail.com
Reported-by: Eric Dumazet <eric.d...@gmail.com>
Fixes: c840ac6af3f8 ("crypto: af_alg - Disallow bind/setkey/...")
Cc: <sta...@vger.kernel.org>
Signed-off-by: Herbert Xu <her...@gondor.apana.org.au>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 0dceaabc6321..3d8e53010cda 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -134,11 +134,13 @@ void af_alg_release_parent(struct sock *sk)
sk = ask->parent;
ask = alg_sk(sk);

- lock_sock(sk);
+ local_bh_disable();
+ bh_lock_sock(sk);
ask->nokey_refcnt -= nokey;
if (!last)
last = !--ask->refcnt;
- release_sock(sk);
+ bh_unlock_sock(sk);
+ local_bh_enable();

if (last)
sock_put(sk);
--
Email: Herbert Xu <her...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 93ad0f96 net: wan: lapbether.c: Use built-in RCU list chec..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1159eb8ee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e89bd00623fe71e

dashboard link: https://syzkaller.appspot.com/bug?extid=c2f1558d49e25cc36e5e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1070cad1e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17de84a5e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c2f155...@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at net/core/sock.c:2935

in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 3198, name:
kworker/0:112
4 locks held by kworker/0:112/3198:
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: __write_once_size
include/linux/compiler.h:226 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set
arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:855 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic_long_set
include/asm-generic/atomic-long.h:40 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_data
kernel/workqueue.c:615 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at:
process_one_work+0x88b/0x1740 kernel/workqueue.c:2235
#1: ffffc9000951fdc0 ((work_completion)(&map->work)){+.+.}, at:
process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239
#2: ffffffff899a3f00 (rcu_read_lock){....}, at: sock_hash_free+0x0/0x540
net/core/sock_map.c:317
#3: ffffc90002478d20 (&htab->buckets[i].lock){+...}, at:
sock_hash_free+0x131/0x540 net/core/sock_map.c:865
Preemption disabled at:
[<ffffffff86341331>] sock_hash_free+0x131/0x540 net/core/sock_map.c:865
CPU: 0 PID: 3198 Comm: kworker/0:112 Not tainted 5.5.0-rc5-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011

Workqueue: events bpf_map_free_deferred

Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800
__might_sleep+0x95/0x190 kernel/sched/core.c:6753
lock_sock_nested+0x39/0x120 net/core/sock.c:2935

lock_sock include/net/sock.h:1531 [inline]
sock_hash_free+0x29f/0x540 net/core/sock_map.c:868
bpf_map_free_deferred+0xb3/0x100 kernel/bpf/syscall.c:327
process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
worker_thread+0x98/0xe40 kernel/workqueue.c:2410

kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

BUG: scheduling while atomic: kworker/0:112/3198/0x00000202
4 locks held by kworker/0:112/3198:
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: __write_once_size
include/linux/compiler.h:226 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set
arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:855 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: atomic_long_set
include/asm-generic/atomic-long.h:40 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at: set_work_data
kernel/workqueue.c:615 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
#0: ffff8880aa426d28 ((wq_completion)events){+.+.}, at:
process_one_work+0x88b/0x1740 kernel/workqueue.c:2235
#1: ffffc9000951fdc0 ((work_completion)(&map->work)){+.+.}, at:
process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239
#2: ffffffff899a3f00 (rcu_read_lock){....}, at: sock_hash_free+0x0/0x540
net/core/sock_map.c:317
#3: ffffc90002478d20 (&htab->buckets[i].lock){+...}, at:
sock_hash_free+0x131/0x540 net/core/sock_map.c:865
Modules linked in:
Preemption disabled at:
[<ffffffff86341331>] sock_hash_free+0x131/0x540 net/core/sock_map.c:865