[moderation] [gfs2?] general protection fault in gfs2_remove_from_journal (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e811c33b1f13 Merge tag 'drm-fixes-2025-11-08' of https://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1609aa92580000
kernel config: https://syzkaller.appspot.com/x/.config?x=929790bc044e87d7
dashboard link: https://syzkaller.appspot.com/bug?extid=8ea1fe5b3267fd7603ec
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [agru...@redhat.com gf...@lists.linux.dev linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-e811c33b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9a1852775b7f/vmlinux-e811c33b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d2f7ca742771/bzImage-e811c33b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8ea1fe...@syzkaller.appspotmail.com

Zero length message leads to an empty skb
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:gfs2_remove_from_journal+0x3cc/0x6d0 fs/gfs2/meta_io.c:359
Code: 3a 4c 89 e7 e8 05 ab 27 fe eb 30 e8 9e 6b c0 fd 48 8b 6c 24 10 4c 8d 65 2c 4c 89 e0 48 c1 e8 03 49 be 00 00 00 00 00 fc ff df <42> 0f b6 04 30 84 c0 4c 8b 3c 24 0f 85 aa 01 00 00 41 ff 04 24 48
RSP: 0018:ffffc9000d4973f8 EFLAGS: 00010207
RAX: 0000000000000005 RBX: ffff88801c0d0000 RCX: 0000000000100000
RDX: ffffc9000e683000 RSI: 0000000000000e73 RDI: 0000000000000e74
RBP: 0000000000000000 R08: ffff8880434e0caf R09: 1ffff1100869c195
R10: dffffc0000000000 R11: ffffed100869c196 R12: 000000000000002c
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880511d41e0
FS: 00007fa4cc38a6c0(0000) GS:ffff88808d730000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000140 CR3: 000000004233d000 CR4: 0000000000352ef0
Call Trace:
<TASK>
gfs2_discard fs/gfs2/aops.c:597 [inline]
gfs2_invalidate_folio+0x579/0x750 fs/gfs2/aops.c:631
folio_invalidate mm/truncate.c:140 [inline]
truncate_cleanup_folio+0x2d8/0x430 mm/truncate.c:160
truncate_inode_pages_range+0x233/0xda0 mm/truncate.c:379
do_gfs2_set_flags fs/gfs2/file.c:254 [inline]
gfs2_fileattr_set+0x80a/0x9b0 fs/gfs2/file.c:311
vfs_fileattr_set+0x932/0xb90 fs/file_attr.c:298
ioctl_setflags+0x180/0x1e0 fs/file_attr.c:334
do_vfs_ioctl+0x8ed/0x1430 fs/ioctl.c:560
__do_sys_ioctl fs/ioctl.c:595 [inline]
__se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa4cb58f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa4cc38a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa4cb7e6090 RCX: 00007fa4cb58f6c9
RDX: 0000200000000140 RSI: 0000000040086602 RDI: 0000000000000005
RBP: 00007fa4cb611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa4cb7e6128 R14: 00007fa4cb7e6090 R15: 00007ffcd258e628
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:gfs2_remove_from_journal+0x3cc/0x6d0 fs/gfs2/meta_io.c:359
Code: 3a 4c 89 e7 e8 05 ab 27 fe eb 30 e8 9e 6b c0 fd 48 8b 6c 24 10 4c 8d 65 2c 4c 89 e0 48 c1 e8 03 49 be 00 00 00 00 00 fc ff df <42> 0f b6 04 30 84 c0 4c 8b 3c 24 0f 85 aa 01 00 00 41 ff 04 24 48
RSP: 0018:ffffc9000d4973f8 EFLAGS: 00010207
RAX: 0000000000000005 RBX: ffff88801c0d0000 RCX: 0000000000100000
RDX: ffffc9000e683000 RSI: 0000000000000e73 RDI: 0000000000000e74
RBP: 0000000000000000 R08: ffff8880434e0caf R09: 1ffff1100869c195
R10: dffffc0000000000 R11: ffffed100869c196 R12: 000000000000002c
R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880511d41e0
FS: 00007fa4cc38a6c0(0000) GS:ffff88808d730000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000140 CR3: 000000004233d000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 3a 4c 89 e7 cmp -0x19(%rcx,%rcx,4),%cl
4: e8 05 ab 27 fe call 0xfe27ab0e
9: eb 30 jmp 0x3b
b: e8 9e 6b c0 fd call 0xfdc06bae
10: 48 8b 6c 24 10 mov 0x10(%rsp),%rbp
15: 4c 8d 65 2c lea 0x2c(%rbp),%r12
19: 4c 89 e0 mov %r12,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 49 be 00 00 00 00 00 movabs $0xdffffc0000000000,%r14
27: fc ff df
* 2a: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 4c 8b 3c 24 mov (%rsp),%r15
35: 0f 85 aa 01 00 00 jne 0x1e5
3b: 41 ff 04 24 incl (%r12)
3f: 48 rex.W


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