syzbot

 sign-in | mailing list | source | docs
🐞 Open [73] 🐞 Fixed [70] 🐞 Invalid [133] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

KASAN: null-ptr-deref Write in prepare_to_wait

Status: fixed on 2021/12/01 19:46
Reported-by: syzbot+b0003676644cf0d6acc4@syzkaller.appspotmail.com
Fix commit: 748786564a35 Revert "io_uring: reinforce cancel on flush during exit"
First crash: 908d, last: 908d
Cause bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH 5.10 00/16] 5.10.78-rc1 review 27 (27) 2021/11/05 14:06
[PATCH v5.10.y 1/1] Revert "io_uring: reinforce cancel on flush during exit" 3 (3) 2021/11/03 07:38
▶ ▼ Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in prepare_to_wait (2) hams syz inconclusive 4 212d 250d 23/26 fixed on 2023/10/12 12:47
linux-4.14 general protection fault in prepare_to_wait C error 11 524d 1774d 0/1 upstream: reported C repro on 2019/06/16 06:33
linux-4.19 general protection fault in prepare_to_wait C error 29 503d 1717d 0/1 upstream: reported C repro on 2019/08/12 18:19
upstream general protection fault in prepare_to_wait hams C done error 285 453d 1938d 0/26 auto-obsoleted due to no activity on 2023/05/27 16:21

Sample crash report:
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write syzkaller/managers/android-5-10/kernel/./include/linux/instrumented.h:101 [inline]
BUG: KASAN: null-ptr-deref in atomic_try_cmpxchg_acquire syzkaller/managers/android-5-10/kernel/./include/asm-generic/atomic-instrumented.h:705 [inline]
BUG: KASAN: null-ptr-deref in queued_spin_lock syzkaller/managers/android-5-10/kernel/./include/asm-generic/qspinlock.h:82 [inline]
BUG: KASAN: null-ptr-deref in do_raw_spin_lock_flags syzkaller/managers/android-5-10/kernel/./include/linux/spinlock.h:195 [inline]
BUG: KASAN: null-ptr-deref in __raw_spin_lock_irqsave syzkaller/managers/android-5-10/kernel/./include/linux/spinlock_api_smp.h:119 [inline]
BUG: KASAN: null-ptr-deref in _raw_spin_lock_irqsave+0xeb/0x210 syzkaller/managers/android-5-10/kernel/kernel/locking/spinlock.c:159
Write of size 4 at addr 0000000000000010 by task syz-executor631/546

CPU: 1 PID: 546 Comm: syz-executor631 Not tainted 5.10.76-syzkaller-01178-g4944ec82ebb9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack syzkaller/managers/android-5-10/kernel/lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b syzkaller/managers/android-5-10/kernel/lib/dump_stack.c:118
 __kasan_report+0x138/0x220 syzkaller/managers/android-5-10/kernel/mm/kasan/report.c:423
 kasan_report+0x51/0x70 syzkaller/managers/android-5-10/kernel/mm/kasan/report.c:436
 check_region_inline syzkaller/managers/android-5-10/kernel/mm/kasan/generic.c:135 [inline]
 kasan_check_range+0x2b6/0x2f0 syzkaller/managers/android-5-10/kernel/mm/kasan/generic.c:186
 __kasan_check_write+0x14/0x20 syzkaller/managers/android-5-10/kernel/mm/kasan/shadow.c:37
 instrument_atomic_read_write syzkaller/managers/android-5-10/kernel/./include/linux/instrumented.h:101 [inline]
 atomic_try_cmpxchg_acquire syzkaller/managers/android-5-10/kernel/./include/asm-generic/atomic-instrumented.h:705 [inline]
 queued_spin_lock syzkaller/managers/android-5-10/kernel/./include/asm-generic/qspinlock.h:82 [inline]
 do_raw_spin_lock_flags syzkaller/managers/android-5-10/kernel/./include/linux/spinlock.h:195 [inline]
 __raw_spin_lock_irqsave syzkaller/managers/android-5-10/kernel/./include/linux/spinlock_api_smp.h:119 [inline]
 _raw_spin_lock_irqsave+0xeb/0x210 syzkaller/managers/android-5-10/kernel/kernel/locking/spinlock.c:159
 prepare_to_wait+0x9c/0x290 syzkaller/managers/android-5-10/kernel/kernel/sched/wait.c:248
 io_uring_cancel_files syzkaller/managers/android-5-10/kernel/fs/io_uring.c:8690 [inline]
 io_uring_cancel_task_requests+0x16a9/0x1ed0 syzkaller/managers/android-5-10/kernel/fs/io_uring.c:8760
 io_uring_flush+0x170/0x6d0 syzkaller/managers/android-5-10/kernel/fs/io_uring.c:8923
 filp_close+0xb0/0x150 syzkaller/managers/android-5-10/kernel/fs/open.c:1319
 close_files syzkaller/managers/android-5-10/kernel/fs/file.c:401 [inline]
 put_files_struct+0x1d4/0x350 syzkaller/managers/android-5-10/kernel/fs/file.c:429
 exit_files+0x80/0xa0 syzkaller/managers/android-5-10/kernel/fs/file.c:458
 do_exit+0x6d9/0x23a0 syzkaller/managers/android-5-10/kernel/kernel/exit.c:808
 do_group_exit+0x16a/0x2d0 syzkaller/managers/android-5-10/kernel/kernel/exit.c:910
 get_signal+0x133e/0x1f80 syzkaller/managers/android-5-10/kernel/kernel/signal.c:2790
 arch_do_signal+0x8d/0x620 syzkaller/managers/android-5-10/kernel/arch/x86/kernel/signal.c:805
 exit_to_user_mode_loop syzkaller/managers/android-5-10/kernel/kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xaa/0xe0 syzkaller/managers/android-5-10/kernel/kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x24/0x40 syzkaller/managers/android-5-10/kernel/kernel/entry/common.c:266
 do_syscall_64+0x3d/0x70 syzkaller/managers/android-5-10/kernel/arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fc6d1589a89
Code: Unable to access opcode bytes at RIP 0x7fc6d1589a5f.
RSP: 002b:00007ffd2b5da728 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 0000000000005193 RCX: 00007fc6d1589a89
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc6d161142c
RBP: 0000000000000032 R08: 00007ffd2b5eb0b8 R09: 0000000000000000
R10: 00007ffd2b5da750 R11: 0000000000000246 R12: 00007fc6d161142c
R13: 00007ffd2b5da750 R14: 00007ffd2b5da770 R15: 0000000000000000
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000010
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 0 P4D 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 546 Comm: syz-executor631 Tainted: G    B             5.10.76-syzkaller-01178-g4944ec82ebb9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:arch_atomic_try_cmpxchg syzkaller/managers/android-5-10/kernel/./arch/x86/include/asm/atomic.h:202 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire syzkaller/managers/android-5-10/kernel/./include/asm-generic/atomic-instrumented.h:707 [inline]
RIP: 0010:queued_spin_lock syzkaller/managers/android-5-10/kernel/./include/asm-generic/qspinlock.h:82 [inline]
RIP: 0010:do_raw_spin_lock_flags syzkaller/managers/android-5-10/kernel/./include/linux/spinlock.h:195 [inline]
RIP: 0010:__raw_spin_lock_irqsave syzkaller/managers/android-5-10/kernel/./include/linux/spinlock_api_smp.h:119 [inline]
RIP: 0010:_raw_spin_lock_irqsave+0x10d/0x210 syzkaller/managers/android-5-10/kernel/kernel/locking/spinlock.c:159
Code: 00 00 00 e8 d5 29 09 fd 4c 89 e7 be 04 00 00 00 e8 c8 29 09 fd 42 8a 04 3b 84 c0 0f 85 be 00 00 00 8b 44 24 40 b9 01 00 00 00 <f0> 41 0f b1 4d 00 75 45 48 c7 44 24 20 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90000f174e0 EFLAGS: 00010097
RAX: 0000000000000000 RBX: 1ffff920001e2ea4 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000f17520
RBP: ffffc90000f175b0 R08: dffffc0000000000 R09: 0000000000000003
R10: fffff520001e2ea5 R11: 0000000000000004 R12: ffffc90000f17520
R13: 0000000000000010 R14: 1ffff920001e2ea0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 000000000640f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 prepare_to_wait+0x9c/0x290 syzkaller/managers/android-5-10/kernel/kernel/sched/wait.c:248
 io_uring_cancel_files syzkaller/managers/android-5-10/kernel/fs/io_uring.c:8690 [inline]
 io_uring_cancel_task_requests+0x16a9/0x1ed0 syzkaller/managers/android-5-10/kernel/fs/io_uring.c:8760
 io_uring_flush+0x170/0x6d0 syzkaller/managers/android-5-10/kernel/fs/io_uring.c:8923
 filp_close+0xb0/0x150 syzkaller/managers/android-5-10/kernel/fs/open.c:1319
 close_files syzkaller/managers/android-5-10/kernel/fs/file.c:401 [inline]
 put_files_struct+0x1d4/0x350 syzkaller/managers/android-5-10/kernel/fs/file.c:429
 exit_files+0x80/0xa0 syzkaller/managers/android-5-10/kernel/fs/file.c:458
 do_exit+0x6d9/0x23a0 syzkaller/managers/android-5-10/kernel/kernel/exit.c:808
 do_group_exit+0x16a/0x2d0 syzkaller/managers/android-5-10/kernel/kernel/exit.c:910
 get_signal+0x133e/0x1f80 syzkaller/managers/android-5-10/kernel/kernel/signal.c:2790
 arch_do_signal+0x8d/0x620 syzkaller/managers/android-5-10/kernel/arch/x86/kernel/signal.c:805
 exit_to_user_mode_loop syzkaller/managers/android-5-10/kernel/kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xaa/0xe0 syzkaller/managers/android-5-10/kernel/kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x24/0x40 syzkaller/managers/android-5-10/kernel/kernel/entry/common.c:266
 do_syscall_64+0x3d/0x70 syzkaller/managers/android-5-10/kernel/arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fc6d1589a89
Code: Unable to access opcode bytes at RIP 0x7fc6d1589a5f.
RSP: 002b:00007ffd2b5da728 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 0000000000005193 RCX: 00007fc6d1589a89
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fc6d161142c
RBP: 0000000000000032 R08: 00007ffd2b5eb0b8 R09: 0000000000000000
R10: 00007ffd2b5da750 R11: 0000000000000246 R12: 00007fc6d161142c
R13: 00007ffd2b5da750 R14: 00007ffd2b5da770 R15: 0000000000000000
Modules linked in:
CR2: 0000000000000010
---[ end trace fe8044f7dc4d8d65 ]---
RIP: 0010:arch_atomic_try_cmpxchg syzkaller/managers/android-5-10/kernel/./arch/x86/include/asm/atomic.h:202 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire syzkaller/managers/android-5-10/kernel/./include/asm-generic/atomic-instrumented.h:707 [inline]
RIP: 0010:queued_spin_lock syzkaller/managers/android-5-10/kernel/./include/asm-generic/qspinlock.h:82 [inline]
RIP: 0010:do_raw_spin_lock_flags syzkaller/managers/android-5-10/kernel/./include/linux/spinlock.h:195 [inline]
RIP: 0010:__raw_spin_lock_irqsave syzkaller/managers/android-5-10/kernel/./include/linux/spinlock_api_smp.h:119 [inline]
RIP: 0010:_raw_spin_lock_irqsave+0x10d/0x210 syzkaller/managers/android-5-10/kernel/kernel/locking/spinlock.c:159
Code: 00 00 00 e8 d5 29 09 fd 4c 89 e7 be 04 00 00 00 e8 c8 29 09 fd 42 8a 04 3b 84 c0 0f 85 be 00 00 00 8b 44 24 40 b9 01 00 00 00 <f0> 41 0f b1 4d 00 75 45 48 c7 44 24 20 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90000f174e0 EFLAGS: 00010097
RAX: 0000000000000000 RBX: 1ffff920001e2ea4 RCX: 0000000000000001
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000f17520
RBP: ffffc90000f175b0 R08: dffffc0000000000 R09: 0000000000000003
R10: fffff520001e2ea5 R11: 0000000000000004 R12: ffffc90000f17520
R13: 0000000000000010 R14: 1ffff920001e2ea0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 000000000640f000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	00 00                	add    %al,(%rax)
   2:	e8 d5 29 09 fd       	callq  0xfd0929dc
   7:	4c 89 e7             	mov    %r12,%rdi
   a:	be 04 00 00 00       	mov    $0x4,%esi
   f:	e8 c8 29 09 fd       	callq  0xfd0929dc
  14:	42 8a 04 3b          	mov    (%rbx,%r15,1),%al
  18:	84 c0                	test   %al,%al
  1a:	0f 85 be 00 00 00    	jne    0xde
  20:	8b 44 24 40          	mov    0x40(%rsp),%eax
  24:	b9 01 00 00 00       	mov    $0x1,%ecx
* 29:	f0 41 0f b1 4d 00    	lock cmpxchg %ecx,0x0(%r13) <-- trapping instruction
  2f:	75 45                	jne    0x76
  31:	48 c7 44 24 20 0e 36 	movq   $0x45e0360e,0x20(%rsp)
  38:	e0 45
  3a:	4b                   	rex.WXB
  3b:	c7                   	.byte 0xc7
  3c:	04 37                	add    $0x37,%al

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/10/29 14:46 android12-5.10-lts 4944ec82ebb9 2353a3ec .config console log report syz C ci2-android-5-10 KASAN: null-ptr-deref Write in prepare_to_wait
2021/10/29 14:30 android12-5.10-lts 4944ec82ebb9 2353a3ec .config console log report info ci2-android-5-10 KASAN: null-ptr-deref Write in prepare_to_wait
* Struck through repros no longer work on HEAD.