Re: general protection fault in f2fs_in_warm_node_list

[Chao Yu]

On 6/27/26 05:28, sanan.hasanou@xxxxxxxxx wrote:
> Good day, dear maintainers,
> 
> We found a bug using a modified version of syzkaller.
> 
> Kernel Branch: 7.0-rc1
> Kernel Config: <https://drive.google.com/open?id=1SkS9U2y8MGrnaXhjJJI5n5SymSSMyYnS>
> Unfortunately, we don't have any reproducer for this bug yet.

Thanks for the report, I guess it should has been fix w/

2d9c4a4ed4ee ("f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io()")

Thanks,

> Thank you!
> 
> Best regards,
> Sanan Hasanov
> 
> Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
> CPU: 0 UID: 0 PID: 3043 Comm: kworker/u8:10 Not tainted 7.0.0-rc1 #1 PREEMPT_{RT,(full)} 
> Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> Workqueue: bat_events batadv_tt_purge
> 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+0xc5/0x2a0 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 19 09 07 fe 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 fc 08 07 fe 4d 3b 37 74 14 e8 b2
> RSP: 0018:ffffc9000e9af568 EFLAGS: 00010216
> RAX: 0000000000000006 RBX: ffffea0000ed41c0 RCX: ffff88802cf2b980
> RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
> RBP: ffffc9000e9af590 R08: ffff8880224bd66b R09: 1ffff11004497acd
> R10: dffffc0000000000 R11: ffffed1004497ace R12: ffff888050544780
> R13: dffffc0000000000 R14: ffff88803e405010 R15: 0000000000000030
> FS:  0000000000000000(0000) GS:ffff8880dc0a8000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055a77139e428 CR3: 0000000033d4c000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  f2fs_write_end_io+0x785/0x1390 fs/f2fs/data.c:400
>  bio_endio+0x936/0x980 block/bio.c:1792
>  blk_update_request+0x5a5/0xe40 block/blk-mq.c:1016
>  blk_mq_end_request+0x4a/0x80 block/blk-mq.c:1178
>  blk_flush_complete_seq+0x667/0xd10 block/blk-flush.c:191
>  flush_end_io+0xc67/0xf40 block/blk-flush.c:251
>  __blk_mq_end_request+0x5bf/0x710 block/blk-mq.c:1168
>  blk_mq_end_request+0x5e/0x80 block/blk-mq.c:1180
>  lo_complete_rq+0xe3/0x260 drivers/block/loop.c:314
>  blk_complete_reqs block/blk-mq.c:1253 [inline]
>  blk_done_softirq+0x10e/0x160 block/blk-mq.c:1258
>  handle_softirqs+0x1c7/0x690 kernel/softirq.c:622
>  __do_softirq kernel/softirq.c:656 [inline]
>  __local_bh_enable_ip+0x16a/0x270 kernel/softirq.c:302
>  local_bh_enable include/linux/bottom_half.h:33 [inline]
>  spin_unlock_bh include/linux/spinlock_rt.h:116 [inline]
>  batadv_tt_global_purge net/batman-adv/translation-table.c:2250 [inline]
>  batadv_tt_purge+0x45c/0x9e0 net/batman-adv/translation-table.c:3510
>  process_one_work kernel/workqueue.c:3275 [inline]
>  process_scheduled_works+0xa5a/0x15e0 kernel/workqueue.c:3358
>  worker_thread+0xab9/0xff0 kernel/workqueue.c:3439
>  kthread+0x355/0x410 kernel/kthread.c:467
>  ret_from_fork+0x49c/0xa10 arch/x86/kernel/process.c:158
>  ret_from_fork_asm+0x11/0x20 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+0xc5/0x2a0 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 19 09 07 fe 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 fc 08 07 fe 4d 3b 37 74 14 e8 b2
> RSP: 0018:ffffc9000e9af568 EFLAGS: 00010216
> RAX: 0000000000000006 RBX: ffffea0000ed41c0 RCX: ffff88802cf2b980
> RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100
> RBP: ffffc9000e9af590 R08: ffff8880224bd66b R09: 1ffff11004497acd
> R10: dffffc0000000000 R11: ffffed1004497ace R12: ffff888050544780
> R13: dffffc0000000000 R14: ffff88803e405010 R15: 0000000000000030
> FS:  0000000000000000(0000) GS:ffff8880dc0a8000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055a77139e428 CR3: 0000000033d4c000 CR4: 00000000000006f0
> ----------------
> 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 19 09 07 fe       	call   0xfe070935
>   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 fc 08 07 fe       	call   0xfe070935
>   39:	4d 3b 37             	cmp    (%r15),%r14
>   3c:	74 14                	je     0x52
>   3e:	e8                   	.byte 0xe8
>   3f:	b2                   	.byte 0xb2
> 
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