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* [syzbot] possible deadlock in lock_system_sleep (2)
@ 2026-10-19 18:08 syzbot
  2026-10-20  0:37 ` Edward Adam Davis
  2026-10-20  1:05 ` [PATCH] kernel/reboot: Avoid potential deadlocks during suspension Edward Adam Davis
  0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2026-10-19 18:08 UTC (permalink / raw)
  To: linux-kernel, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    32c52ec87d62 x86/insn-eval: Fix shadowed segment index in ..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=120a93a9580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c4b098695335c89f
dashboard link: https://syzkaller.appspot.com/bug?extid=1f0fbc2561b3e5d51b91
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=141d098e580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1f0fbc2561b3e5d51b91@syzkaller.appspotmail.com

============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.3.5755/5950 is trying to acquire lock:
ffffffff8fc04760 (system_transition_mutex){+.+.}-{4:4}, at: lock_system_sleep+0x49/0x70 kernel/power/main.c:71

but task is already holding lock:
ffffffff8fc04760 (system_transition_mutex){+.+.}-{4:4}, at: __do_sys_reboot kernel/reboot.c:774 [inline]
ffffffff8fc04760 (system_transition_mutex){+.+.}-{4:4}, at: __se_sys_reboot+0x223/0x460 kernel/reboot.c:738

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

       CPU0
       ----
  lock(system_transition_mutex);
  lock(system_transition_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

locks held by syz.3.5755/5950: 1, last CPU#0:
 #0: ffffffff8fc04760 (system_transition_mutex){+.+.}-{4:4}, at: __do_sys_reboot kernel/reboot.c:774 [inline]
 #0: ffffffff8fc04760 (system_transition_mutex){+.+.}-{4:4}, at: __se_sys_reboot+0x223/0x460 kernel/reboot.c:738

stack backtrace:
CPU: 0 UID: 0 PID: 5950 Comm: syz.3.5755 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x27a/0x290 kernel/locking/lockdep.c:3085
 check_deadlock kernel/locking/lockdep.c:3137 [inline]
 validate_chain kernel/locking/lockdep.c:3939 [inline]
 __lock_acquire+0x25db/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
 lock_system_sleep+0x49/0x70 kernel/power/main.c:71
 hibernate+0x162/0x680 kernel/power/hibernate.c:784
 __do_sys_reboot kernel/reboot.c:816 [inline]
 __se_sys_reboot+0x2ba/0x460 kernel/reboot.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdb2419f809
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff22cee98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a9
RAX: ffffffffffffffda RBX: 00007ffff22cefc8 RCX: 00007fdb2419f809
RDX: 00000000d000fce2 RSI: 0000000028121969 RDI: 00000000fee1dead
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffff22cefc8
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffff22cefb8
R13: 0000000000000002 R14: 00007fdb24222cc0 R15: 0000000000000002
 </TASK>


---
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^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-10-20  1:47 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-10-19 18:08 [syzbot] possible deadlock in lock_system_sleep (2) syzbot
2026-10-20  0:37 ` Edward Adam Davis
2026-10-20  1:47   ` syzbot
2026-10-20  1:05 ` [PATCH] kernel/reboot: Avoid potential deadlocks during suspension Edward Adam Davis

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