syzbot


WARNING in netfs_writepages (3)

Status: upstream: reported C repro on 2026/07/06 21:44
Subsystems: netfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+0da43efa72f88bd3a8af@syzkaller.appspotmail.com
First crash: 4d23h, last: 2d17h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
e569e5fe-4c6b-4ba2-9ee9-74ef927521de assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in netfs_writepages (3) 2026/07/06 00:02 2026/07/06 00:02 2026/07/06 00:49 93f579545ae410f5bccfa141d2e7bf03178f036c

			
		
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] netfs: fix ENOMEM handling in netfs_writepages() to drain all dirty folios 2 (2) 2026/07/07 06:13
[syzbot] [netfs?] WARNING in netfs_writepages (3) 0 (2) 2026/07/07 05:34
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in netfs_writepages (2) netfs -1 1 339d 335d 0/29 auto-obsoleted due to no activity on 2025/11/12 09:56
upstream WARNING in netfs_writepages netfs -1 C error 11 496d 599d 0/29 auto-obsoleted due to no activity on 2025/06/08 22:51
Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/07/07 05:34 31m yun.zhou@windriver.com patch upstream OK log

Sample crash report:
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fe029a25fac R14: 00007fe029a25fa0 R15: 00007fe029a25fa0
 </TASK>
------------[ cut here ]------------
folio != NULL
WARNING: fs/netfs/write_issue.c:603 at netfs_writepages+0x883/0xa10 fs/netfs/write_issue.c:603, CPU#3: syz.0.17/5919
Modules linked in:
CPU: 3 UID: 0 PID: 5919 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:netfs_writepages+0x883/0xa10 fs/netfs/write_issue.c:603
Code: 48 89 df e8 3f 8b 7b ff 48 8b 4c 24 08 48 89 da 4c 89 e6 4c 89 f7 e8 ec 34 7f ff 48 85 c0 0f 84 c1 fe ff ff e8 0e c7 3d ff 90 <0f> 0b 90 e9 b3 fe ff ff e8 00 c7 3d ff 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000415f178 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffea00014f2580 RCX: ffffffff824b4bda
RDX: ffff88802bcea540 RSI: ffffffff82cc0992 RDI: ffff88802bcea540
RBP: fffffffffffffff4 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc9000415f348
R13: ffff888046848bc0 R14: ffff888046848dd8 R15: dffffc0000000000
FS:  0000555567857500(0000) GS:ffff8880d60ec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002901 CR3: 0000000025ac6000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 do_writepages+0x278/0x600 mm/page-writeback.c:2571
 filemap_writeback+0x22d/0x2e0 mm/filemap.c:387
 v9fs_mmap_vm_close fs/9p/vfs_file.c:496 [inline]
 v9fs_mmap_vm_close+0x137/0x1e0 fs/9p/vfs_file.c:489
 vma_close mm/internal.h:190 [inline]
 vms_clean_up_area mm/vma.c:1318 [inline]
 __mmap_setup mm/vma.c:2476 [inline]
 __mmap_region+0x890/0x2db0 mm/vma.c:2756
 mmap_region+0x527/0x620 mm/vma.c:2860
 do_mmap+0xc63/0x12f0 mm/mmap.c:560
 vm_mmap_pgoff+0x29e/0x470 mm/util.c:581
 ksys_mmap_pgoff+0x3cb/0x610 mm/mmap.c:606
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe02979de59
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:00007fff3ad0a858 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe029a25fa0 RCX: 00007fe02979de59
RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fff3ad0a8c0 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fe029a25fac R14: 00007fe029a25fa0 R15: 00007fe029a25fa0
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/05 08:34 upstream 7404ce516372 fcece630 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in netfs_writepages
2026/07/05 08:07 upstream 7404ce516372 fcece630 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in netfs_writepages
2026/07/05 07:42 upstream 7404ce516372 fcece630 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in netfs_writepages
2026/07/07 12:19 upstream 0e35b9b6ec0f 76cdc0c0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in netfs_writepages
2026/07/06 16:53 upstream 8cdeaa50eae8 88b240e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in netfs_writepages
2026/07/05 07:17 upstream 7404ce516372 fcece630 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in netfs_writepages
2026/07/06 00:40 upstream f105f3631d51 fcece630 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in netfs_writepages
* Struck through repros no longer work on HEAD.