KASAN: null-ptr-deref Write in f2fs_stop_gc

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
android-6-1	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread origin:lts	12	C		error	5	30d	300d	0/2	upstream: reported C repro on 2025/07/15 15:45
android-5-15	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread origin:lts	12	C		error	5	24d	300d	0/2	upstream: reported C repro on 2025/07/15 08:24
upstream	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread f2fs	22	C	done		5	609d	656d	28/29	fixed on 2024/10/22 11:56
linux-6.1	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread origin:lts-only	12	C		inconclusive	13	1d03h	499d	0/3	upstream: reported C repro on 2024/12/29 01:22

Kernel

Title

Rank 🛈

android-6-1

KASAN: null-ptr-deref Write in f2fs_stop_gc_thread origin:lts

error

30d

300d

0/2

upstream: reported C repro on 2025/07/15 15:45

android-5-15

KASAN: null-ptr-deref Write in f2fs_stop_gc_thread origin:lts

error

24d

300d

0/2

upstream: reported C repro on 2025/07/15 08:24

upstream

KASAN: null-ptr-deref Write in f2fs_stop_gc_thread f2fs

done

609d

656d

28/29

fixed on 2024/10/22 11:56

linux-6.1

KASAN: null-ptr-deref Write in f2fs_stop_gc_thread origin:lts-only

inconclusive

1d03h

499d

0/3

upstream: reported C repro on 2024/12/29 01:22


Created	Duration	User	Repo	Result
2026/04/21 00:05	14m	retest repro	android13-5.10-lts	report log
2026/04/21 00:05	16m	retest repro	android13-5.10-lts	report log
2026/04/21 00:05	11m	retest repro	android13-5.10-lts	report log
2026/04/21 00:05	12m	retest repro	android13-5.10-lts	report log
2026/02/04 20:54	5m	retest repro	android13-5.10-lts	report log
2026/02/04 20:54	6m	retest repro	android13-5.10-lts	report log
2026/02/04 20:54	6m	retest repro	android13-5.10-lts	report log
2026/02/04 20:54	7m	retest repro	android13-5.10-lts	report log
2025/12/21 11:11	14m	retest repro	android13-5.10-lts	report log
2025/11/21 08:52	5m	retest repro	android13-5.10-lts	report log

Created	Duration	User	Repo	Result
2026/04/05 22:16	1h35m	bisect fix	android13-5.10-lts	OK (0) job log log
2026/03/06 21:12	51m	bisect fix	android13-5.10-lts	OK (0) job log log
2026/01/21 19:25	1h20m	bisect fix	android13-5.10-lts	OK (0) job log log
2025/08/03 02:09	1h57m	bisect fix	android13-5.10-lts	OK (0) job log log
2025/06/19 08:35	1h29m	bisect fix	android13-5.10-lts	OK (0) job log log
2025/05/19 11:17	1h09m	bisect fix	android13-5.10-lts	OK (0) job log log

Created

Duration

User

Patch

Repo

Result

2026/04/05 22:16

1h35m

bisect fix

android13-5.10-lts

OK (0) job log log

2026/03/06 21:12

51m

bisect fix

android13-5.10-lts

OK (0) job log log

2026/01/21 19:25

1h20m

bisect fix

android13-5.10-lts

OK (0) job log log

2025/08/03 02:09

1h57m

bisect fix

android13-5.10-lts

OK (0) job log log

2025/06/19 08:35

1h29m

bisect fix

android13-5.10-lts

OK (0) job log log

2025/05/19 11:17

1h09m

bisect fix

android13-5.10-lts

OK (0) job log log

================================================================== 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/asm-generic/atomic-instrumented.h:142 [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:108 [inline] BUG: KASAN: null-ptr-deref in kthread_stop+0x3a/0x3e0 kernel/kthread.c:640 Write of size 4 at addr 0000000000000020 by task syz.0.63/783 CPU: 1 PID: 783 Comm: syz.0.63 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118 __kasan_report mm/kasan/report.c:439 [inline] kasan_report+0xd8/0x130 mm/kasan/report.c:452 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/asm-generic/atomic-instrumented.h:142 [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:108 [inline] kthread_stop+0x3a/0x3e0 kernel/kthread.c:640 f2fs_stop_gc_thread+0x65/0xb0 fs/f2fs/gc.c:199 f2fs_ioc_shutdown fs/f2fs/file.c:2415 [inline] __f2fs_ioctl+0x70d6/0xcc90 fs/f2fs/file.c:4384 f2fs_ioctl+0x149/0x240 fs/f2fs/file.c:4469 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fb57db72dd9 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:00007fb57d9b4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb57ddec090 RCX: 00007fb57db72dd9 RDX: 0000200000000080 RSI: 000000008004587d RDI: 0000000000000004 RBP: 00007fb57dc08d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb57ddec128 R14: 00007fb57ddec090 R15: 00007ffd405a6cc8 ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 129ed6067 P4D 129ed6067 PUD 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 783 Comm: syz.0.63 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:arch_atomic_fetch_add arch/x86/include/asm/atomic.h:184 [inline] RIP: 0010:atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:143 [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:108 [inline] RIP: 0010:kthread_stop+0x40/0x3e0 kernel/kthread.c:640 Code: 00 fc ff df e8 01 44 22 00 0f 1f 44 00 00 e8 f7 43 22 00 4c 8d 73 20 4c 89 f7 be 04 00 00 00 e8 46 c8 5c 00 41 bf 01 00 00 00 <f0> 44 0f c1 7b 20 31 ff 44 89 fe e8 80 47 22 00 45 85 ff 0f 84 32 RSP: 0018:ffffc90000e17898 EFLAGS: 00010246 RAX: ffff88810e8a9300 RBX: 0000000000000000 RCX: 0000000000000286 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffffc90000e178c0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff0dcf848 R12: 1ffff110259ab925 R13: dffffc0000000000 R14: 0000000000000020 R15: 0000000000000001 FS: 00007fb57d9b46c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 000000012ecc7000 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:199 f2fs_ioc_shutdown fs/f2fs/file.c:2415 [inline] __f2fs_ioctl+0x70d6/0xcc90 fs/f2fs/file.c:4384 f2fs_ioctl+0x149/0x240 fs/f2fs/file.c:4469 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x121/0x1a0 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fb57db72dd9 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:00007fb57d9b4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb57ddec090 RCX: 00007fb57db72dd9 RDX: 0000200000000080 RSI: 000000008004587d RDI: 0000000000000004 RBP: 00007fb57dc08d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb57ddec128 R14: 00007fb57ddec090 R15: 00007ffd405a6cc8 Modules linked in: CR2: 0000000000000020 ---[ end trace 61d26f71f819323f ]--- RIP: 0010:arch_atomic_fetch_add arch/x86/include/asm/atomic.h:184 [inline] RIP: 0010:atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:143 [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:108 [inline] RIP: 0010:kthread_stop+0x40/0x3e0 kernel/kthread.c:640 Code: 00 fc ff df e8 01 44 22 00 0f 1f 44 00 00 e8 f7 43 22 00 4c 8d 73 20 4c 89 f7 be 04 00 00 00 e8 46 c8 5c 00 41 bf 01 00 00 00 <f0> 44 0f c1 7b 20 31 ff 44 89 fe e8 80 47 22 00 45 85 ff 0f 84 32 RSP: 0018:ffffc90000e17898 EFLAGS: 00010246 RAX: ffff88810e8a9300 RBX: 0000000000000000 RCX: 0000000000000286 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffffc90000e178c0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff0dcf848 R12: 1ffff110259ab925 R13: dffffc0000000000 R14: 0000000000000020 R15: 0000000000000001 FS: 00007fb57d9b46c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 000000012ecc7000 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: 01 44 22 00 add %eax,0x0(%rdx,%riz,1) 9: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) e: e8 f7 43 22 00 call 0x22440a 13: 4c 8d 73 20 lea 0x20(%rbx),%r14 17: 4c 89 f7 mov %r14,%rdi 1a: be 04 00 00 00 mov $0x4,%esi 1f: e8 46 c8 5c 00 call 0x5cc86a 24: 41 bf 01 00 00 00 mov $0x1,%r15d * 2a: f0 44 0f c1 7b 20 lock xadd %r15d,0x20(%rbx) <-- trapping instruction 30: 31 ff xor %edi,%edi 32: 44 89 fe mov %r15d,%esi 35: e8 80 47 22 00 call 0x2247ba 3a: 45 85 ff test %r15d,%r15d 3d: 0f .byte 0xf 3e: 84 32 test %dh,(%rdx)

Crashes (7):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/05/11 06:25	android13-5.10-lts	5feb5545d40a	29233ece	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread
2025/04/02 20:28	android13-5.10-lts	094fc3778d6b	c799dfdd	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread
2025/04/02 09:59	android13-5.10-lts	094fc3778d6b	c799dfdd	.config	strace log	report	syz / log	C		[disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread
2025/04/02 05:23	android13-5.10-lts	094fc3778d6b	b8645499	.config	console log	report	syz / log	C		[disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread
2025/04/02 23:07	android13-5.10-lts	094fc3778d6b	c799dfdd	.config	console log	report	syz / log			[disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread
2025/04/02 01:54	android13-5.10-lts	094fc3778d6b	b8645499	.config	console log	report	syz / log			[disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_stop_gc_thread
2025/10/29 12:52	android13-5.10-lts	2ece552169c2	fd2207e7	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-android-5-10	KASAN: use-after-free Read in f2fs_stop_gc_thread

Crashes (7):

Assets (help?)