KASAN: null-ptr-deref Write in f2fs_issue

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
android-5-15	KASAN: null-ptr-deref Write in f2fs_issue_flush origin:lts	12	C		error	6	19d	154d	0/2	upstream: reported C repro on 2025/09/30 19:35
linux-6.1	KASAN: null-ptr-deref Write in f2fs_issue_flush origin:lts-only	12	C		error	3	50d	154d	0/3	upstream: reported C repro on 2025/10/01 01:02

Kernel

Title

Rank 🛈

android-5-15

KASAN: null-ptr-deref Write in f2fs_issue_flush origin:lts

error

19d

154d

0/2

upstream: reported C repro on 2025/09/30 19:35

linux-6.1

KASAN: null-ptr-deref Write in f2fs_issue_flush origin:lts-only

error

50d

154d

0/3

upstream: reported C repro on 2025/10/01 01:02


Created	Duration	User	Repo	Result
2026/02/24 21:49	5m	retest repro	android13-5.10-lts	report log
2026/02/08 05:00	6m	retest repro	android13-5.10-lts	report log
2026/02/08 05:00	5m	retest repro	android13-5.10-lts	report log
2026/02/08 05:00	7m	retest repro	android13-5.10-lts	report log
2025/11/25 22:59	9m	retest repro	android13-5.10-lts	report log
2025/11/25 22:59	11m	retest repro	android13-5.10-lts	report log
2025/11/25 22:59	12m	retest repro	android13-5.10-lts	report log
2025/11/25 22:59	9m	retest repro	android13-5.10-lts	report log

Created	Duration	User	Patch	Repo	Result
2026/01/25 04:05	38m	bisect fix		android13-5.10-lts	OK (0) job log log
2025/12/26 01:51	2h14m	bisect fix		android13-5.10-lts	OK (0) job log log

Created

Duration

User

Patch

Repo

Result

2026/01/25 04:05

38m

bisect fix

android13-5.10-lts

OK (0) job log log

2025/12/26 01:51

2h14m

bisect fix

android13-5.10-lts

OK (0) job log log

WARNING: the mand mount option is being deprecated and will be removed in v5.15! ====================================================== F2FS-fs (loop2): Try to recover all the superblocks, ret: 0 ================================================================== BUG: KASAN: null-ptr-deref in f2fs_issue_flush+0x161/0x8b0 fs/f2fs/segment.c:-1 Write of size 4 at addr 0000000000000024 by task syz.2.17/357 CPU: 0 PID: 357 Comm: syz.2.17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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 f2fs_issue_flush+0x161/0x8b0 fs/f2fs/segment.c:-1 f2fs_do_sync_file+0x1325/0x1d80 fs/f2fs/file.c:385 f2fs_sync_file+0x103/0x150 fs/f2fs/file.c:401 vfs_fsync_range fs/sync.c:202 [inline] vfs_fsync+0x18d/0x1a0 fs/sync.c:216 __loop_update_dio+0x260/0x610 drivers/block/loop.c:212 loop_update_dio drivers/block/loop.c:638 [inline] loop_configure+0xbf5/0x1250 drivers/block/loop.c:1160 lo_ioctl+0xa9a/0x1f60 drivers/block/loop.c:1697 __blkdev_driver_ioctl block/ioctl.c:240 [inline] blkdev_ioctl+0x2db/0x640 block/ioctl.c:635 block_ioctl+0xae/0x100 fs/block_dev.c:1888 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: 0033:0x7f39bfbb2f79 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:00007fffe8190e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f39bfe2cfa0 RCX: 00007f39bfbb2f79 RDX: 00002000000002c0 RSI: 0000000000004c0a RDI: 0000000000000003 RBP: 00007f39bfc497e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f39bfe2cfac R14: 00007f39bfe2cfa0 R15: 00007f39bfe2cfa0 ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000024 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 10fe4c067 P4D 10fe4c067 PUD 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 0 PID: 357 Comm: syz.2.17 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:arch_atomic_inc fs/f2fs/segment.c:-1 [inline] RIP: 0010:atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline] RIP: 0010:f2fs_issue_flush+0x172/0x8b0 fs/f2fs/segment.c:678 Code: 4b 58 ff 4c 89 64 24 28 49 83 c4 24 4c 89 e7 be 04 00 00 00 e8 1f cb 92 ff 81 e3 00 04 00 00 0f 85 52 01 00 00 4c 89 64 24 08 <f0> 41 ff 04 24 4c 8b 74 24 20 4d 8d ae 6c 0c 00 00 4d 89 ec 49 c1 RSP: 0018:ffffc90000ca6ec0 EFLAGS: 00010246 RAX: ffff88810cd12700 RBX: 0000000000000000 RCX: 0000000000000286 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffffc90000ca6fd0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff0dcf448 R12: 0000000000000024 R13: ffffc90000ca6f20 R14: 0000000000000000 R15: 1ffff92000194de0 FS: 000055555b2df500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000024 CR3: 000000010ce50000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: f2fs_do_sync_file+0x1325/0x1d80 fs/f2fs/file.c:385 f2fs_sync_file+0x103/0x150 fs/f2fs/file.c:401 vfs_fsync_range fs/sync.c:202 [inline] vfs_fsync+0x18d/0x1a0 fs/sync.c:216 __loop_update_dio+0x260/0x610 drivers/block/loop.c:212 loop_update_dio drivers/block/loop.c:638 [inline] loop_configure+0xbf5/0x1250 drivers/block/loop.c:1160 lo_ioctl+0xa9a/0x1f60 drivers/block/loop.c:1697 __blkdev_driver_ioctl block/ioctl.c:240 [inline] blkdev_ioctl+0x2db/0x640 block/ioctl.c:635 block_ioctl+0xae/0x100 fs/block_dev.c:1888 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: 0033:0x7f39bfbb2f79 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:00007fffe8190e08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f39bfe2cfa0 RCX: 00007f39bfbb2f79 RDX: 00002000000002c0 RSI: 0000000000004c0a RDI: 0000000000000003 RBP: 00007f39bfc497e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f39bfe2cfac R14: 00007f39bfe2cfa0 R15: 00007f39bfe2cfa0 Modules linked in: CR2: 0000000000000024 ---[ end trace 974f4c9c2442fec6 ]--- RIP: 0010:arch_atomic_inc fs/f2fs/segment.c:-1 [inline] RIP: 0010:atomic_inc include/asm-generic/atomic-instrumented.h:241 [inline] RIP: 0010:f2fs_issue_flush+0x172/0x8b0 fs/f2fs/segment.c:678 Code: 4b 58 ff 4c 89 64 24 28 49 83 c4 24 4c 89 e7 be 04 00 00 00 e8 1f cb 92 ff 81 e3 00 04 00 00 0f 85 52 01 00 00 4c 89 64 24 08 <f0> 41 ff 04 24 4c 8b 74 24 20 4d 8d ae 6c 0c 00 00 4d 89 ec 49 c1 RSP: 0018:ffffc90000ca6ec0 EFLAGS: 00010246 RAX: ffff88810cd12700 RBX: 0000000000000000 RCX: 0000000000000286 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff RBP: ffffc90000ca6fd0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff0dcf448 R12: 0000000000000024 R13: ffffc90000ca6f20 R14: 0000000000000000 R15: 1ffff92000194de0 FS: 000055555b2df500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000024 CR3: 000000010ce50000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 4b 58 rex.WXB pop %r8 2: ff 4c 89 64 decl 0x64(%rcx,%rcx,4) 6: 24 28 and $0x28,%al 8: 49 83 c4 24 add $0x24,%r12 c: 4c 89 e7 mov %r12,%rdi f: be 04 00 00 00 mov $0x4,%esi 14: e8 1f cb 92 ff call 0xff92cb38 19: 81 e3 00 04 00 00 and $0x400,%ebx 1f: 0f 85 52 01 00 00 jne 0x177 25: 4c 89 64 24 08 mov %r12,0x8(%rsp) * 2a: f0 41 ff 04 24 lock incl (%r12) <-- trapping instruction 2f: 4c 8b 74 24 20 mov 0x20(%rsp),%r14 34: 4d 8d ae 6c 0c 00 00 lea 0xc6c(%r14),%r13 3b: 4d 89 ec mov %r13,%r12 3e: 49 rex.WB 3f: c1 .byte 0xc1

Crashes (6):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/02/10 18:34	android13-5.10-lts	0be127d3b2ec	91d776d3	.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_issue_flush
2025/11/11 21:18	android13-5.10-lts	ab3e1c0dd1ff	4e1406b4	.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_issue_flush
2025/11/11 18:27	android13-5.10-lts	ab3e1c0dd1ff	4e1406b4	.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_issue_flush
2025/11/09 07:10	android13-5.10-lts	ab3e1c0dd1ff	4e1406b4	.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_issue_flush
2025/11/09 06:50	android13-5.10-lts	ab3e1c0dd1ff	4e1406b4	.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_issue_flush
2025/11/09 06:29	android13-5.10-lts	ab3e1c0dd1ff	4e1406b4	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-android-5-10	KASAN: null-ptr-deref Write in f2fs_issue_flush

Crashes (6):

Assets (help?)