Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an
issue:
general protection fault in f2fs_in_warm_node_list
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000006: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0
PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
02/12/2026
RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:2260 [inline]
RIP: 0010:is_node_folio fs/f2fs/f2fs.h:2270 [inline]
RIP: 0010:f2fs_in_warm_node_list+0xbd/0x290 fs/f2fs/node.c:330
Code: 00 00 4d 03 3c 24 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8
71 a9 fd fd 4d 8b 3f 49 83 c7 30 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c
89 ff e8 54 a9 fd fd 4d 3b 37 74 19 e8 da
RSP: 0018:ffffc900001479a8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffffea0000aa0c80 RCX: ffff88801c6e9e80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: dffffc0000000000 R08: ffffffff8f6a32b7 R09: 1ffffffff1ed4656
R10: dffffc0000000000 R11: fffffbfff1ed4657 R12: ffff8880394a8798
R13: dffffc0000000000 R14: ffff88805c522950 R15: 0000000000000030
FS: 0000000000000000(0000) GS:ffff888126340000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd37652e50 CR3: 0000000044d76000 CR4: 00000000003526f0
Call Trace:
<TASK>
f2fs_write_end_io+0x691/0x1020 fs/f2fs/data.c:400
blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
blk_flush_complete_seq+0x687/0xce0 block/blk-flush.c:191
flush_end_io+0xc40/0xf30 block/blk-flush.c:251
__blk_mq_end_request+0x4a9/0x680 block/blk-mq.c:1168
blk_complete_reqs block/blk-mq.c:1253 [inline]
blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
handle_softirqs+0x1de/0x6f0 kernel/softirq.c:622
run_ksoftirqd+0x52/0x180 kernel/softirq.c:1063
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:2260 [inline]
RIP: 0010:is_node_folio fs/f2fs/f2fs.h:2270 [inline]
RIP: 0010:f2fs_in_warm_node_list+0xbd/0x290 fs/f2fs/node.c:330
Code: 00 00 4d 03 3c 24 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8
71 a9 fd fd 4d 8b 3f 49 83 c7 30 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c
89 ff e8 54 a9 fd fd 4d 3b 37 74 19 e8 da
RSP: 0018:ffffc900001479a8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffffea0000aa0c80 RCX: ffff88801c6e9e80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
RBP: dffffc0000000000 R08: ffffffff8f6a32b7 R09: 1ffffffff1ed4656
R10: dffffc0000000000 R11: fffffbfff1ed4657 R12: ffff8880394a8798
R13: dffffc0000000000 R14: ffff88805c522950 R15: 0000000000000030
FS: 0000000000000000(0000) GS:ffff888126340000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd37652e50 CR3: 0000000044d76000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 4d 03 3c 24 add (%r12),%r15
6: 4c 89 f8 mov %r15,%rax
9: 48 c1 e8 03 shr $0x3,%rax
d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
12: 74 08 je 0x1c
14: 4c 89 ff mov %r15,%rdi
17: e8 71 a9 fd fd call 0xfdfda98d
1c: 4d 8b 3f mov (%r15),%r15
1f: 49 83 c7 30 add $0x30,%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping
instruction
2f: 74 08 je 0x39
31: 4c 89 ff mov %r15,%rdi
34: e8 54 a9 fd fd call 0xfdfda98d
39: 4d 3b 37 cmp (%r15),%r14
3c: 74 19 je 0x57
3e: e8 .byte 0xe8
3f: da .byte 0xda
Tested on:
commit: af4e9ef3 uaccess: Fix scoped_user_read_access() for 'p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=129818d6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a019678b1a3a692
dashboard link: https://syzkaller.appspot.com/bug?extid=6e4cb1cac5efc96ea0ca
compiler: Debian clang version 21.1.8
(++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=11948d5a580000
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