[syzbot] [bpf?] [net?] possible deadlock in sk_psock_skb_ingress_enqueue

From: syzbot
Date: Wed May 29 2024 - 12:52:53 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 44382b3ed6b2 bpf: Fix potential integer overflow in resolv..
git tree: bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1556297c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=17ffd15f654c98ba
dashboard link: https://syzkaller.appspot.com/bug?extid=53cf0afa7b308038a6db
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e2dad9cbbe0c/disk-44382b3e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f67186323c24/vmlinux-44382b3e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/02d46501b164/bzImage-44382b3e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+53cf0afa7b308038a6db@xxxxxxxxxxxxxxxxxxxxxxxxx

======================================================
WARNING: possible circular locking dependency detected
6.9.0-syzkaller-08559-g44382b3ed6b2 #0 Not tainted
------------------------------------------------------
syz-executor.3/7164 is trying to acquire lock:
ffff88804a4d7858 (&ei->socket.wq.wait){..-.}-{2:2}, at: __wake_up_common_lock+0x25/0x1e0 kernel/sched/wait.c:105

but task is already holding lock:
ffff88801e9623f0 (clock-AF_UNIX){++..}-{2:2}, at: sk_psock_data_ready include/linux/skmsg.h:468 [inline]
ffff88801e9623f0 (clock-AF_UNIX){++..}-{2:2}, at: sk_psock_skb_ingress_enqueue+0x328/0x450 net/core/skmsg.c:555

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #5 (clock-AF_UNIX){++..}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_write_lock_bh include/linux/rwlock_api_smp.h:202 [inline]
_raw_write_lock_bh+0x35/0x50 kernel/locking/spinlock.c:334
sk_psock_drop+0x34/0x500 net/core/skmsg.c:837
__sock_map_delete net/core/sock_map.c:435 [inline]
sock_map_delete_elem+0x1a2/0x250 net/core/sock_map.c:461
0xffffffffa00017f2
bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
__bpf_prog_run include/linux/filter.h:682 [inline]
bpf_prog_run include/linux/filter.h:698 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
bpf_trace_run8+0x564/0x630 kernel/trace/bpf_trace.c:2450
__bpf_trace_jbd2_handle_stats+0x47/0x60 include/trace/events/jbd2.h:210
trace_jbd2_handle_stats include/trace/events/jbd2.h:210 [inline]
jbd2_journal_stop+0xd0a/0xd80 fs/jbd2/transaction.c:1869
__ext4_journal_stop+0xfd/0x1a0 fs/ext4/ext4_jbd2.c:134
ext4_create+0x2f9/0x550 fs/ext4/namei.c:2843
lookup_open fs/namei.c:3505 [inline]
open_last_lookups fs/namei.c:3574 [inline]
path_openat+0x1425/0x3240 fs/namei.c:3804
do_filp_open+0x235/0x490 fs/namei.c:3834
do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1432
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&stab->lock){+...}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x35/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
__sock_map_delete net/core/sock_map.c:429 [inline]
sock_map_delete_elem+0x175/0x250 net/core/sock_map.c:461
bpf_prog_10a0f827fc0335db+0x3/0x21
bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
__bpf_prog_run include/linux/filter.h:691 [inline]
bpf_prog_run include/linux/filter.h:698 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
bpf_trace_run4+0x334/0x590 kernel/trace/bpf_trace.c:2446
trace_mmap_lock_acquire_returned include/trace/events/mmap_lock.h:52 [inline]
__mmap_lock_do_trace_acquire_returned+0x5c8/0x630 mm/mmap_lock.c:237
__mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline]
mmap_read_trylock include/linux/mmap_lock.h:166 [inline]
get_mmap_lock_carefully mm/memory.c:5628 [inline]
lock_mm_and_find_vma+0x213/0x2f0 mm/memory.c:5688
do_user_addr_fault arch/x86/mm/fault.c:1355 [inline]
handle_page_fault arch/x86/mm/fault.c:1475 [inline]
exc_page_fault+0x1a9/0x8a0 arch/x86/mm/fault.c:1533
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:65
copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline]
copy_to_user_iter lib/iov_iter.c:25 [inline]
iterate_ubuf include/linux/iov_iter.h:29 [inline]
iterate_and_advance2 include/linux/iov_iter.h:245 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x26b/0x1960 lib/iov_iter.c:185
copy_page_to_iter+0xb1/0x160 lib/iov_iter.c:362
pipe_read+0x59c/0x13e0 fs/pipe.c:327
call_read_iter include/linux/fs.h:2114 [inline]
new_sync_read fs/read_write.c:395 [inline]
vfs_read+0x97b/0xb70 fs/read_write.c:476
ksys_read+0x1a0/0x2c0 fs/read_write.c:619
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (lock#10){+.+.}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
__mmap_lock_do_trace_acquire_returned+0xa8/0x630 mm/mmap_lock.c:237
__mmap_lock_trace_acquire_returned include/linux/mmap_lock.h:36 [inline]
mmap_read_trylock include/linux/mmap_lock.h:166 [inline]
stack_map_get_build_id_offset+0x9b2/0x9d0 kernel/bpf/stackmap.c:141
__bpf_get_stack+0x4ad/0x5a0 kernel/bpf/stackmap.c:449
____bpf_get_stack_raw_tp kernel/trace/bpf_trace.c:1994 [inline]
bpf_get_stack_raw_tp+0x1a3/0x240 kernel/trace/bpf_trace.c:1984
bpf_prog_9dc0996bccb7470f+0x16/0x6c
bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
__bpf_prog_run include/linux/filter.h:691 [inline]
bpf_prog_run include/linux/filter.h:698 [inline]
__bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2444
trace_tlb_flush+0x118/0x140 include/trace/events/tlb.h:38
switch_mm_irqs_off+0x7cb/0xae0
context_switch kernel/sched/core.c:5392 [inline]
__schedule+0x1066/0x4a50 kernel/sched/core.c:6745
preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6924
preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6948
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
futex_wake+0x516/0x5c0 kernel/futex/waitwake.c:198
do_futex+0x392/0x560 kernel/futex/syscalls.c:107
__do_sys_futex kernel/futex/syscalls.c:179 [inline]
__se_sys_futex+0x3f9/0x480 kernel/futex/syscalls.c:160
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&rq->__lock){-.-.}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
_raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
raw_spin_rq_lock kernel/sched/sched.h:1406 [inline]
rq_lock kernel/sched/sched.h:1702 [inline]
task_fork_fair+0x61/0x1e0 kernel/sched/fair.c:12709
sched_cgroup_fork+0x37c/0x410 kernel/sched/core.c:4844
copy_process+0x2217/0x3dc0 kernel/fork.c:2499
kernel_clone+0x226/0x8f0 kernel/fork.c:2797
user_mode_thread+0x132/0x1a0 kernel/fork.c:2875
rest_init+0x23/0x300 init/main.c:707
start_kernel+0x47a/0x500 init/main.c:1084
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:507
x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:488
common_startup_64+0x13e/0x147

-> #1 (&p->pi_lock){-.-.}-{2:2}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:553 [inline]
try_to_wake_up+0xb0/0x1470 kernel/sched/core.c:4262
autoremove_wake_function+0x16/0x110 kernel/sched/wait.c:384
__wake_up_common kernel/sched/wait.c:89 [inline]
__wake_up_common_lock+0x130/0x1e0 kernel/sched/wait.c:106
sock_def_readable+0x20f/0x5b0 net/core/sock.c:3353
unix_dgram_sendmsg+0x148e/0x1f80 net/unix/af_unix.c:2113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
__sys_sendto+0x3a4/0x4f0 net/socket.c:2191
__do_sys_sendto net/socket.c:2203 [inline]
__se_sys_sendto net/socket.c:2199 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2199
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ei->socket.wq.wait){..-.}-{2:2}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
__wake_up_common_lock+0x25/0x1e0 kernel/sched/wait.c:105
sock_def_readable+0x20f/0x5b0 net/core/sock.c:3353
sk_psock_skb_ingress_enqueue+0x388/0x450 net/core/skmsg.c:555
sk_psock_skb_ingress_self+0x292/0x340 net/core/skmsg.c:606
sk_psock_verdict_apply+0x3bd/0x460 net/core/skmsg.c:1008
sk_psock_verdict_recv+0x335/0x590 net/core/skmsg.c:1202
unix_read_skb+0xd9/0x180 net/unix/af_unix.c:2502
sk_psock_verdict_data_ready+0xab/0x390 net/core/skmsg.c:1223
unix_dgram_sendmsg+0x148e/0x1f80 net/unix/af_unix.c:2113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
&ei->socket.wq.wait --> &stab->lock --> clock-AF_UNIX

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
rlock(clock-AF_UNIX);
lock(&stab->lock);
lock(clock-AF_UNIX);
lock(&ei->socket.wq.wait);

*** DEADLOCK ***

3 locks held by syz-executor.3/7164:
#0: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#0: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#0: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: sk_psock_verdict_recv+0x4d/0x590 net/core/skmsg.c:1185
#1: ffff88801e9623f0 (clock-AF_UNIX){++..}-{2:2}, at: sk_psock_data_ready include/linux/skmsg.h:468 [inline]
#1: ffff88801e9623f0 (clock-AF_UNIX){++..}-{2:2}, at: sk_psock_skb_ingress_enqueue+0x328/0x450 net/core/skmsg.c:555
#2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
#2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
#2: ffffffff8e333d20 (rcu_read_lock){....}-{1:2}, at: sock_def_readable+0xd7/0x5b0 net/core/sock.c:3350

stack backtrace:
CPU: 0 PID: 7164 Comm: syz-executor.3 Not tainted 6.9.0-syzkaller-08559-g44382b3ed6b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
__wake_up_common_lock+0x25/0x1e0 kernel/sched/wait.c:105
sock_def_readable+0x20f/0x5b0 net/core/sock.c:3353
sk_psock_skb_ingress_enqueue+0x388/0x450 net/core/skmsg.c:555
sk_psock_skb_ingress_self+0x292/0x340 net/core/skmsg.c:606
sk_psock_verdict_apply+0x3bd/0x460 net/core/skmsg.c:1008
sk_psock_verdict_recv+0x335/0x590 net/core/skmsg.c:1202
unix_read_skb+0xd9/0x180 net/unix/af_unix.c:2502
sk_psock_verdict_data_ready+0xab/0x390 net/core/skmsg.c:1223
unix_dgram_sendmsg+0x148e/0x1f80 net/unix/af_unix.c:2113
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:745
____sys_sendmsg+0x525/0x7d0 net/socket.c:2584
___sys_sendmsg net/socket.c:2638 [inline]
__sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f8967cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8f891de0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8f897ac050 RCX: 00007f8f8967cee9
RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000004
RBP: 00007f8f896c949e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f8f897ac050 R15: 00007ffc340af978
</TASK>

---
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Next message: Namhyung Kim: "Re: [PATCH v2] bpf: Allocate bpf_event_entry with node info"
Previous message: harshad shirwadkar: "Re: [PATCH v3 1/2] ext4: fix fast commit inode enqueueing during a full journal commit"
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