syzbot


WARNING in file_remove_privs_flags

Status: moderation: reported on 2026/05/12 16:39
Subsystems: fs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+bc273027d5643e48e5b3@syzkaller.appspotmail.com
First crash: 35d, last: 30d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
5577bda1-fb3c-4606-abaa-db7b7218cd61 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in file_remove_privs_flags 2026/05/17 18:13 2026/05/17 18:13 2026/05/17 19:07 de5aae85e5f28e2fa1c7deefcc24fe286abe5140
Discussions (5)
Title Replies (including bot) Last reply
[PATCH v4] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/06/07 10:54
Re: [PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 8 (8) 2026/05/30 23:57
[PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/05/25 03:40
[PATCH] loop: add sync_blockdev() in __loop_clr_fd() to prevent UAF 7 (7) 2026/05/22 11:50
[PATCH v2] loop: Fix NULL pointer dereference by synchronizing lo_release and loop_queue_rq 1 (1) 2026/05/15 01:38

Sample crash report:
------------[ cut here ]------------
d_inode(dentry) != file_inode(file)
WARNING: ./include/linux/fs.h:1368 at file_dentry include/linux/fs.h:1368 [inline], CPU#0: kworker/u8:14/1529
WARNING: ./include/linux/fs.h:1368 at file_remove_privs_flags+0x58c/0x640 fs/inode.c:2313, CPU#0: kworker/u8:14/1529
Modules linked in:
CPU: 0 UID: 0 PID: 1529 Comm: kworker/u8:14 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: loop3 loop_workfn
RIP: 0010:file_dentry include/linux/fs.h:1368 [inline]
RIP: 0010:file_remove_privs_flags+0x58c/0x640 fs/inode.c:2313
Code: 00 75 4d 44 89 e8 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 1f 82 83 ff e9 90 fe ff ff e8 15 82 83 ff 90 <0f> 0b 90 e9 85 fb ff ff 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c b7
RSP: 0018:ffffc90006adf480 EFLAGS: 00010293
RAX: ffffffff8240f23b RBX: ffff888035ab6ca0 RCX: ffff888029b19ec0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90006adf5d8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f11cdf R12: ffff888041268ab8
R13: 1ffff11006b56d94 R14: 0000000000000000 R15: 1ffff1100824d157
FS:  0000000000000000(0000) GS:ffff888126176000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555802efa68 CR3: 000000001fbda000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 shmem_file_write_iter+0xaa/0x120 mm/shmem.c:3472
 lo_rw_aio+0xc80/0xf00 include/linux/percpu-rwsem.h:-1
 do_req_filebacked drivers/block/loop.c:433 [inline]
 loop_handle_cmd drivers/block/loop.c:1925 [inline]
 loop_process_work+0x637/0x11b0 drivers/block/loop.c:1960
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/08 16:34 upstream 917719c412c4 b2988c17 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in file_remove_privs_flags
2026/05/13 20:54 linux-next e98d21c170b0 fec2a7ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in file_remove_privs_flags
* Struck through repros no longer work on HEAD.