syzbot

 sign-in | mailing list | source | docs
🐞 Open [131]
🐞 Fixed [2]
🐞 Invalid [238]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

KASAN: null-ptr-deref Write in incfs_kill_sb

Status: premoderation: reported on 2026/05/02 13:38
Reported-by: syzbot+675eba943b2213e9b5d3@syzkaller.appspotmail.com
First crash: 1d21h, last: 1d21h
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 KASAN: null-ptr-deref Write in incfs_kill_sb 12 1 200d 200d 0/2 auto-obsoleted due to no activity on 2026/01/14 00:20
android-5-10 general protection fault in incfs_kill_sb 2 C done 380 1528d 1530d 2/2 fixed on 2022/05/12 07:47
android-54 general protection fault in incfs_kill_sb 2 C 2965 1515d 1550d 2/2 fixed on 2022/04/19 10:20

Sample crash report:
RSP: 002b:00007ffda3708b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe412b9e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffda3708bc0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffda3709c50
R13: 00007fe412c32120 R14: 0000000000014fd7 R15: 00007ffda3709c90
 </TASK>
---[ end trace 0000000000000000 ]---
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
BUG: KASAN: null-ptr-deref in atomic_inc_return include/linux/atomic/atomic-instrumented.h:198 [inline]
BUG: KASAN: null-ptr-deref in ihold+0x20/0x60 fs/inode.c:455
Write of size 4 at addr 0000000000000170 by task syz-executor/294

CPU: 0 PID: 294 Comm: syz-executor Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_inc_return include/linux/atomic/atomic-instrumented.h:198 [inline]
 ihold+0x20/0x60 fs/inode.c:455
 incfs_kill_sb+0x105/0x220 fs/incfs/vfs.c:1995
 deactivate_locked_super+0xb5/0x120 fs/super.c:336
 deactivate_super+0xaf/0xe0 fs/super.c:367
 cleanup_mnt+0x474/0x500 fs/namespace.c:1192
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe412b9e017
Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffda3708b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe412b9e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffda3708bc0
RBP: 00007ffda3708bc0 R08: 00007ffda3709bc0 R09: 00000000ffffffff
R13: 00007fe412c32120 R14: 0000000000014fd7 R15: 00007ffda3709c90
 </TASK>
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000170
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 132f19067 P4D 132f19067 PUD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 294 Comm: syz-executor Tainted: G    B   W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:165 [inline]
RIP: 0010:arch_atomic_inc_return include/linux/atomic/atomic-arch-fallback.h:440 [inline]
RIP: 0010:atomic_inc_return include/linux/atomic/atomic-instrumented.h:199 [inline]
RIP: 0010:ihold+0x26/0x60 fs/inode.c:455
Code: 33 36 7c df 55 48 89 e5 41 56 53 48 89 fb e8 61 06 ab ff 48 8d bb 70 01 00 00 be 04 00 00 00 e8 10 a3 f0 ff 41 be 01 00 00 00 <f0> 44 0f c1 b3 70 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 51
RSP: 0018:ffffc9000db77c78 EFLAGS: 00010246
RAX: ffff888108e10000 RBX: 0000000000000000 RCX: ffff888108e10000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000db77c88 R08: ffffffff87b757e7 R09: 1ffffffff0f6eafc
R10: dffffc0000000000 R11: fffffbfff0f6eafd R12: ffff8881340fd374
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000000
FS:  0000555570c79500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000170 CR3: 000000013034d000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 d_delete_notify include/linux/fsnotify.h:289 [inline]
 vfs_rmdir+0x25f/0x500 fs/namei.c:4211
 incfs_kill_sb+0x105/0x220 fs/incfs/vfs.c:1995
 deactivate_locked_super+0xb5/0x120 fs/super.c:336
 deactivate_super+0xaf/0xe0 fs/super.c:367
 cleanup_mnt+0x474/0x500 fs/namespace.c:1192
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1199
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe412b9e017
Code: a2 c7 05 dc 06 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffda3708b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fe412b9e017
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffda3708bc0
RBP: 00007ffda3708bc0 R08: 00007ffda3709bc0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffda3709c50
R13: 00007fe412c32120 R14: 0000000000014fd7 R15: 00007ffda3709c90
 </TASK>
Modules linked in:
CR2: 0000000000000170
---[ end trace 0000000000000000 ]---
RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:165 [inline]
RIP: 0010:arch_atomic_inc_return include/linux/atomic/atomic-arch-fallback.h:440 [inline]
RIP: 0010:atomic_inc_return include/linux/atomic/atomic-instrumented.h:199 [inline]
RIP: 0010:ihold+0x26/0x60 fs/inode.c:455
Code: 33 36 7c df 55 48 89 e5 41 56 53 48 89 fb e8 61 06 ab ff 48 8d bb 70 01 00 00 be 04 00 00 00 e8 10 a3 f0 ff 41 be 01 00 00 00 <f0> 44 0f c1 b3 70 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 51
RSP: 0018:ffffc9000db77c78 EFLAGS: 00010246
RAX: ffff888108e10000 RBX: 0000000000000000 RCX: ffff888108e10000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000db77c88 R08: ffffffff87b757e7 R09: 1ffffffff0f6eafc
R10: dffffc0000000000 R11: fffffbfff0f6eafd R12: ffff8881340fd374
R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000000
FS:  0000555570c79500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000170 CR3: 000000013034d000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	33 36                	xor    (%rsi),%esi
   2:	7c df                	jl     0xffffffe3
   4:	55                   	push   %rbp
   5:	48 89 e5             	mov    %rsp,%rbp
   8:	41 56                	push   %r14
   a:	53                   	push   %rbx
   b:	48 89 fb             	mov    %rdi,%rbx
   e:	e8 61 06 ab ff       	call   0xffab0674
  13:	48 8d bb 70 01 00 00 	lea    0x170(%rbx),%rdi
  1a:	be 04 00 00 00       	mov    $0x4,%esi
  1f:	e8 10 a3 f0 ff       	call   0xfff0a334
  24:	41 be 01 00 00 00    	mov    $0x1,%r14d
* 2a:	f0 44 0f c1 b3 70 01 	lock xadd %r14d,0x170(%rbx) <-- trapping instruction
  31:	00 00
  33:	41 ff c6             	inc    %r14d
  36:	bf 02 00 00 00       	mov    $0x2,%edi
  3b:	44 89 f6             	mov    %r14d,%esi
  3e:	e8                   	.byte 0xe8
  3f:	51                   	push   %rcx

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/02 13:37 android14-6.1 1e4e23ff0f90 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 KASAN: null-ptr-deref Write in incfs_kill_sb
* Struck through repros no longer work on HEAD.