syzbot


WARNING in ext4_dirty_folio

Status: upstream: reported C repro on 2025/09/21 20:59
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+63515cf575687a69e6b5@syzkaller.appspotmail.com
First crash: 93d, last: 4d16h
Bug presence (1)
Date Name Commit Repro Result
2025/12/21 upstream (ToT) 9094662f6707 C [report] WARNING in ext4_dirty_folio
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in ext4_dirty_folio mm -1 C error 7438 4d13h 1368d 0/29 upstream: reported C repro on 2022/03/26 15:24
linux-6.1 WARNING in ext4_dirty_folio origin:upstream missing-backport -1 C done 26 3d13h 899d 0/3 upstream: reported C repro on 2023/07/08 13:03

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5926 at fs/ext4/inode.c:3583 ext4_dirty_folio+0x159/0x310 fs/ext4/inode.c:3583
Modules linked in:
CPU: 1 PID: 5926 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:ext4_dirty_folio+0x159/0x310 fs/ext4/inode.c:3583
Code: 49 83 3f 00 74 1f e8 36 5a 53 ff 48 8b 3c 24 48 89 de 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 ec 83 c9 ff e8 17 5a 53 ff <0f> 0b eb dd e8 0e 5a 53 ff 0f 0b eb af e8 05 5a 53 ff 48 89 df 48
RSP: 0018:ffffc90003437998 EFLAGS: 00010293
RAX: ffffffff823236a9 RBX: ffffea0001b09980 RCX: ffff88802b879e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 1ffffd4000361330 R08: ffffea0001b09987 R09: 1ffffd4000361330
R10: dffffc0000000000 R11: fffff94000361331 R12: dffffc0000000000
R13: 1ffffd4000361331 R14: 0000000000000001 R15: ffffea0001b099a8
FS:  00007f85149cf6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f85149cef98 CR3: 00000000767c6000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 set_page_dirty_lock+0xfc/0x2c0 mm/page-writeback.c:2825
 fuse_copy_finish+0x104/0x200 fs/fuse/dev.c:678
 fuse_dev_do_read+0xc44/0x11a0 fs/fuse/dev.c:1302
 fuse_dev_read+0x14d/0x1d0 fs/fuse/dev.c:1367
 call_read_iter include/linux/fs.h:2012 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x431/0x920 fs/read_write.c:470
 ksys_read+0x147/0x250 fs/read_write.c:613
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8513b8f749
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:00007f85149cf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f8513de6090 RCX: 00007f8513b8f749
RDX: 0000000000002020 RSI: 0000200000000940 RDI: 0000000000000005
RBP: 00007f8513c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8513de6128 R14: 00007f8513de6090 R15: 00007fffd10880d8
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/19 17:37 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan WARNING in ext4_dirty_folio
2025/12/19 16:36 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ext4_dirty_folio
2025/12/19 16:34 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ext4_dirty_folio
2025/12/19 16:33 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in ext4_dirty_folio
2025/09/21 20:59 linux-6.6.y af1544b5d072 67c37560 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan WARNING in ext4_dirty_folio
* Struck through repros no longer work on HEAD.