==================================================================
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.2.17/482
CPU: 1 PID: 482 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+0x21/0x30 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
f2fs_issue_flush+0x161/0x8b0 fs/f2fs/segment.c:-1
f2fs_do_sync_file+0x11aa/0x1bb0 fs/f2fs/file.c:381
f2fs_ioc_commit_atomic_write fs/f2fs/file.c:2210 [inline]
__f2fs_ioctl+0x31ac/0xb580 fs/f2fs/file.c:4225
f2fs_ioctl+0x149/0x240 fs/f2fs/file.c:4313
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: 0033:0x7f62aba90539
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:00007f62ab8f5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f62abcfbfa0 RCX: 00007f62aba90539
RDX: 0000000000000000 RSI: 000000000000f502 RDI: 0000000000000005
RBP: 00007f62abb23ee0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f62abcfc038 R14: 00007f62abcfbfa0 R15: 00007ffd5eca5e58
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000024
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 116b76067 P4D 116b76067 PUD 0
Oops: 0002 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 482 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/linux/atomic/atomic-instrumented.h:182 [inline]
RIP: 0010:f2fs_issue_flush+0x172/0x8b0 fs/f2fs/segment.c:595
Code: 03 52 ff 4c 89 64 24 28 49 83 c4 24 4c 89 e7 be 04 00 00 00 e8 7f 2c 91 ff 81 e3 00 04 00 00 0f 85 52 01 00 00 4c 89 64 24 08 41 ff 04 24 4c 8b 74 24 20 4d 8d ae 3c 0c 00 00 4d 89 ec 49 c1
RSP: 0018:ffffc900020576c0 EFLAGS: 00010246
RAX: ffff8881186f4f00 RBX: 0000000000000000 RCX: ffff8881186f4f00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff
RBP: ffffc900020577d0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18a4c R12: 0000000000000024
R13: ffffc90002057720 R14: 0000000000000000 R15: 1ffff9200040aee0
FS: 00007f62ab8f56c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000024 CR3: 0000000112c00000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
f2fs_do_sync_file+0x11aa/0x1bb0 fs/f2fs/file.c:381
f2fs_ioc_commit_atomic_write fs/f2fs/file.c:2210 [inline]
__f2fs_ioctl+0x31ac/0xb580 fs/f2fs/file.c:4225
f2fs_ioctl+0x149/0x240 fs/f2fs/file.c:4313
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: 0033:0x7f62aba90539
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:00007f62ab8f5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f62abcfbfa0 RCX: 00007f62aba90539
RDX: 0000000000000000 RSI: 000000000000f502 RDI: 0000000000000005
RBP: 00007f62abb23ee0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f62abcfc038 R14: 00007f62abcfbfa0 R15: 00007ffd5eca5e58
Modules linked in:
CR2: 0000000000000024
---[ end trace bf949ca981f9b737 ]---
RIP: 0010:arch_atomic_inc fs/f2fs/segment.c:-1 [inline]
RIP: 0010:atomic_inc include/linux/atomic/atomic-instrumented.h:182 [inline]
RIP: 0010:f2fs_issue_flush+0x172/0x8b0 fs/f2fs/segment.c:595
Code: 03 52 ff 4c 89 64 24 28 49 83 c4 24 4c 89 e7 be 04 00 00 00 e8 7f 2c 91 ff 81 e3 00 04 00 00 0f 85 52 01 00 00 4c 89 64 24 08 41 ff 04 24 4c 8b 74 24 20 4d 8d ae 3c 0c 00 00 4d 89 ec 49 c1
RSP: 0018:ffffc900020576c0 EFLAGS: 00010246
RAX: ffff8881186f4f00 RBX: 0000000000000000 RCX: ffff8881186f4f00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00000000ffffffff
RBP: ffffc900020577d0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18a4c R12: 0000000000000024
R13: ffffc90002057720 R14: 0000000000000000 R15: 1ffff9200040aee0
FS: 00007f62ab8f56c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000024 CR3: 0000000112c00000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 03 52 ff add -0x1(%rdx),%edx
3: 4c 89 64 24 28 mov %r12,0x28(%rsp)
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 7f 2c 91 ff call 0xff912c98
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 3c 0c 00 00 lea 0xc3c(%r14),%r13
3b: 4d 89 ec mov %r13,%r12
3e: 49 rex.WB
3f: c1 .byte 0xc1