==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: null-ptr-deref in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:111 [inline]
BUG: KASAN: null-ptr-deref in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: null-ptr-deref in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: null-ptr-deref in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: null-ptr-deref in get_task_struct include/linux/sched/task.h:106 [inline]
BUG: KASAN: null-ptr-deref in kthread_stop+0x3a/0x3e0 kernel/kthread.c:675
Write of size 4 at addr 0000000000000028 by task syz.5.186/1513
CPU: 0 PID: 1513 Comm: syz.5.186 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:88
dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
__kasan_report mm/kasan/report.c:431 [inline]
kasan_report+0xe7/0x140 mm/kasan/report.c:444
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:101 [inline]
atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:111 [inline]
__refcount_add include/linux/refcount.h:193 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
get_task_struct include/linux/sched/task.h:106 [inline]
kthread_stop+0x3a/0x3e0 kernel/kthread.c:675
f2fs_stop_gc_thread+0x65/0xb0 fs/f2fs/gc.c:198
f2fs_ioc_shutdown fs/f2fs/file.c:2314 [inline]
__f2fs_ioctl+0x5fb8/0xb580 fs/f2fs/file.c:4233
f2fs_ioctl+0x149/0x240 fs/f2fs/file.c:4314
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:860
__x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4fae997079
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4fae3db028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4faebc3080 RCX: 00007f4fae997079
RDX: 0000200000000140 RSI: 000000008004587d RDI: 0000000000000005
RBP: 00007f4faea29a4c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4faebc3080 R15: 00007ffeff70faa8
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000028
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 10fcdf067 P4D 10fcdf067 PUD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 1513 Comm: syz.5.186 Tainted: G B syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:arch_atomic_fetch_add arch/x86/include/asm/atomic.h:184 [inline]
RIP: 0010:atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:112 [inline]
RIP: 0010:__refcount_add include/linux/refcount.h:193 [inline]
RIP: 0010:__refcount_inc include/linux/refcount.h:250 [inline]
RIP: 0010:refcount_inc include/linux/refcount.h:267 [inline]
RIP: 0010:get_task_struct include/linux/sched/task.h:106 [inline]
RIP: 0010:kthread_stop+0x40/0x3e0 kernel/kthread.c:675
Code: 00 fc ff df e8 31 23 24 00 0f 1f 44 00 00 e8 27 23 24 00 4c 8d 73 28 4c 89 f7 be 04 00 00 00 e8 c6 53 63 00 41 bf 01 00 00 00 44 0f c1 7b 28 31 ff 44 89 fe e8 b0 26 24 00 45 85 ff 0f 84 32
RSP: 0018:ffffc90002727918 EFLAGS: 00010246
RAX: ffff888118eecf00 RBX: 0000000000000000 RCX: ffff888118eecf00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff
RBP: ffffc90002727940 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18a4c R12: 1ffff11024430523
R13: dffffc0000000000 R14: 0000000000000028 R15: 0000000000000001
FS: 00007f4fae3db6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000028 CR3: 000000012e1e4000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
f2fs_stop_gc_thread+0x65/0xb0 fs/f2fs/gc.c:198
f2fs_ioc_shutdown fs/f2fs/file.c:2314 [inline]
__f2fs_ioctl+0x5fb8/0xb580 fs/f2fs/file.c:4233
f2fs_ioctl+0x149/0x240 fs/f2fs/file.c:4314
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:860
__x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4fae997079
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4fae3db028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4faebc3080 RCX: 00007f4fae997079
RDX: 0000200000000140 RSI: 000000008004587d RDI: 0000000000000005
RBP: 00007f4faea29a4c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4faebc3080 R15: 00007ffeff70faa8
Modules linked in:
CR2: 0000000000000028
---[ end trace 8f7197c73cbb2b06 ]---
RIP: 0010:arch_atomic_fetch_add arch/x86/include/asm/atomic.h:184 [inline]
RIP: 0010:atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:112 [inline]
RIP: 0010:__refcount_add include/linux/refcount.h:193 [inline]
RIP: 0010:__refcount_inc include/linux/refcount.h:250 [inline]
RIP: 0010:refcount_inc include/linux/refcount.h:267 [inline]
RIP: 0010:get_task_struct include/linux/sched/task.h:106 [inline]
RIP: 0010:kthread_stop+0x40/0x3e0 kernel/kthread.c:675
Code: 00 fc ff df e8 31 23 24 00 0f 1f 44 00 00 e8 27 23 24 00 4c 8d 73 28 4c 89 f7 be 04 00 00 00 e8 c6 53 63 00 41 bf 01 00 00 00 44 0f c1 7b 28 31 ff 44 89 fe e8 b0 26 24 00 45 85 ff 0f 84 32
RSP: 0018:ffffc90002727918 EFLAGS: 00010246
RAX: ffff888118eecf00 RBX: 0000000000000000 RCX: ffff888118eecf00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff
RBP: ffffc90002727940 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18a4c R12: 1ffff11024430523
R13: dffffc0000000000 R14: 0000000000000028 R15: 0000000000000001
FS: 00007f4fae3db6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000028 CR3: 000000012e1e4000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 fc add %bh,%ah
2: ff lcall (bad)
3: df e8 fucomip %st(0),%st
5: 31 23 xor %esp,(%rbx)
7: 24 00 and $0x0,%al
9: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
e: e8 27 23 24 00 call 0x24233a
13: 4c 8d 73 28 lea 0x28(%rbx),%r14
17: 4c 89 f7 mov %r14,%rdi
1a: be 04 00 00 00 mov $0x4,%esi
1f: e8 c6 53 63 00 call 0x6353ea
24: 41 bf 01 00 00 00 mov $0x1,%r15d
* 2a: f0 44 0f c1 7b 28 lock xadd %r15d,0x28(%rbx) <-- trapping instruction
30: 31 ff xor %edi,%edi
32: 44 89 fe mov %r15d,%esi
35: e8 b0 26 24 00 call 0x2426ea
3a: 45 85 ff test %r15d,%r15d
3d: 0f .byte 0xf
3e: 84 32 test %dh,(%rdx)