===================================== WARNING: bad unlock balance detected! syzkaller #0 Not tainted ------------------------------------- syz.0.1010/9733 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.0.1010/9733: #0: ffffffff8e61b890 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x4ba7/0x7690 kernel/fork.c:2274 stack backtrace: CPU: 0 UID: 0 PID: 9733 Comm: syz.0.1010 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+0x104/0x460 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:626 RIP: 0023:0xf72a8370 Code: 4c 24 04 85 c9 0f 84 5f 39 fe ff 8b 54 24 0c 85 d2 0f 84 53 39 fe ff 53 56 8b 74 24 18 89 cb 8b 4c 24 10 b8 b3 01 00 00 cd 80 <85> c0 74 09 5e 5b 0f 8c 34 39 fe ff c3 31 ed 83 e4 f0 83 ec 0c 56 RSP: 002b:00000000ff9939e4 EFLAGS: 00000286 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00000000ff993a50 RCX: 0000000000000058 RDX: 00000000f7235c50 RSI: 00000000f54feb40 RDI: 00000000ffffffd4 RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ------------[ cut here ]------------ pvqspinlock: lock 0xffff888024cf9280 has corrupted value 0x0! WARNING: CPU: 1 PID: 9733 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: 9733 Comm: syz.0.1010 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 80 81 ad 8b e8 da fa e5 f5 90 <0f> 0b 90 90 e9 64 ff ff ff 90 0f 0b 48 89 df 4c 89 04 24 e8 51 6c RSP: 0018:ffffc900036379c8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff888024cf9280 RCX: ffffffff817a02f8 RDX: ffff8880279b4880 RSI: ffffffff817a0305 RDI: 0000000000000001 RBP: ffff888024cf9288 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 6c6e697073717670 R12: ffff888024cf9290 R13: ffff888024cf9280 R14: 00000000003d0f00 R15: ffff8880218f8000 FS: 0000000000000000(0000) GS:ffff8880975bd000(0063) knlGS:0000000056d10440 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000800004c8 CR3: 0000000070b81000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 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+0x104/0x460 arch/x86/entry/syscall_32.c:172 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:626 RIP: 0023:0xf72a8370 Code: Unable to access opcode bytes at 0xf72a8346. RSP: 002b:00000000ff9939e4 EFLAGS: 00000286 ORIG_RAX: 00000000000001b3 RAX: ffffffffffffffda RBX: 00000000ff993a50 RCX: 0000000000000058 RDX: 00000000f7235c50 RSI: 00000000f54feb40 RDI: 00000000ffffffd4 RBP: 000000000000000b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 4c 24 04 rex.WR and $0x4,%al 3: 85 c9 test %ecx,%ecx 5: 0f 84 5f 39 fe ff je 0xfffe396a b: 8b 54 24 0c mov 0xc(%rsp),%edx f: 85 d2 test %edx,%edx 11: 0f 84 53 39 fe ff je 0xfffe396a 17: 53 push %rbx 18: 56 push %rsi 19: 8b 74 24 18 mov 0x18(%rsp),%esi 1d: 89 cb mov %ecx,%ebx 1f: 8b 4c 24 10 mov 0x10(%rsp),%ecx 23: b8 b3 01 00 00 mov $0x1b3,%eax 28: cd 80 int $0x80 * 2a: 85 c0 test %eax,%eax <-- trapping instruction 2c: 74 09 je 0x37 2e: 5e pop %rsi 2f: 5b pop %rbx 30: 0f 8c 34 39 fe ff jl 0xfffe396a 36: c3 ret 37: 31 ed xor %ebp,%ebp 39: 83 e4 f0 and $0xfffffff0,%esp 3c: 83 ec 0c sub $0xc,%esp 3f: 56 push %rsi