===================================== WARNING: bad unlock balance detected! syzkaller #0 Not tainted ------------------------------------- syz.4.3372/20649 is trying to release lock (&sighand->siglock) at: [] spin_unlock include/linux/spinlock.h:391 [inline] [] copy_process+0x6b72/0x7690 kernel/fork.c:2432 but there are no more locks to release! other info that might help us debug this: 1 lock held by syz.4.3372/20649: #0: ffffffff8e61bbd0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x4ba7/0x7690 kernel/fork.c:2274 stack backtrace: CPU: 1 UID: 0 PID: 20649 Comm: syz.4.3372 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_unlock_imbalance_bug kernel/locking/lockdep.c:5298 [inline] print_unlock_imbalance_bug+0x11b/0x130 kernel/locking/lockdep.c:5272 __lock_release kernel/locking/lockdep.c:5537 [inline] lock_release+0x242/0x2f0 kernel/locking/lockdep.c:5889 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline] _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_process+0x6b72/0x7690 kernel/fork.c:2432 kernel_clone+0xfc/0x930 kernel/fork.c:2605 __do_sys_clone3+0x212/0x290 kernel/fork.c:2909 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] do_int80_emulation+0x104/0x3e0 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:626 RIP: 0023:0xf7278380 Code: Unable to access opcode bytes at 0xf7278356. RSP: 002b:00000000ffc1cc34 EFLAGS: 00000286 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00000000ffc1cca0 RCX: 0000000000000058 RDX: 00000000f7205c60 RSI: 00000000f54d6b40 RDI: 00000000ffffffd4 RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ------------[ cut here ]------------ pvqspinlock: lock 0xffff888026099280 has corrupted value 0x0! WARNING: CPU: 1 PID: 20649 at kernel/locking/qspinlock_paravirt.h:504 __pv_queued_spin_unlock_slowpath+0x237/0x330 kernel/locking/qspinlock_paravirt.h:504 Modules linked in: CPU: 1 UID: 0 PID: 20649 Comm: syz.4.3372 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:__pv_queued_spin_unlock_slowpath+0x237/0x330 kernel/locking/qspinlock_paravirt.h:504 Code: 03 0f b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 67 41 8b 55 00 4c 89 ee 48 c7 c7 00 84 ad 8b e8 9a 8b e5 f5 90 <0f> 0b 90 90 e9 64 ff ff ff 90 0f 0b 48 89 df 4c 89 04 24 e8 21 04 RSP: 0000:ffffc9000367f9c8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff888026099280 RCX: ffffffff817a02f8 RDX: ffff888054f24880 RSI: ffffffff817a0305 RDI: 0000000000000001 RBP: ffff888026099288 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 6c6e697073717670 R12: ffff888026099290 R13: ffff888026099280 R14: 00000000003d0f00 R15: ffff8880737e4880 FS: 0000000000000000(0000) GS:ffff8880975ba000(0063) knlGS:0000000056db1440 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00007f6603d0c3a0 CR3: 0000000062ca4000 CR4: 0000000000352ef0 Call Trace: __raw_callee_save___pv_queued_spin_unlock_slowpath+0x15/0x30 .slowpath+0x9/0x18 pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:562 [inline] queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline] do_raw_spin_unlock+0x172/0x230 kernel/locking/spinlock_debug.c:142 __raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_unlock+0x1e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_process+0x6b72/0x7690 kernel/fork.c:2432 kernel_clone+0xfc/0x930 kernel/fork.c:2605 __do_sys_clone3+0x212/0x290 kernel/fork.c:2909 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] do_int80_emulation+0x104/0x3e0 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:626 RIP: 0023:0xf7278380 Code: Unable to access opcode bytes at 0xf7278356. RSP: 002b:00000000ffc1cc34 EFLAGS: 00000286 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00000000ffc1cca0 RCX: 0000000000000058 RDX: 00000000f7205c60 RSI: 00000000f54d6b40 RDI: 00000000ffffffd4 RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000