WARNING in btrfs_quota_enable (2)

Status: upstream: reported on 2026/08/25 15:41
Subsystems: btrfs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+11ac036337245d7faf6d@syzkaller.appspotmail.com
First crash: 49d, last: 2d11h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
89db6b95 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in btrfs_quota_enable (2) 2026/08/23 01:43 2026/08/23 01:43 2026/08/23 02:21 1e72964b
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Title Replies (including bot) Last reply
[syzbot] [btrfs?] WARNING in btrfs_quota_enable (2) 0 (1) 2026/08/25 15:41
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in btrfs_quota_enable origin:upstream -1 syz, C error 8 11d 1051d 0/3 upstream: reported C repro on 2023/11/24 03:47
upstream WARNING in btrfs_quota_enable btrfs -1 1 1140d 1136d 0/29 auto-obsoleted due to no activity on 2023/12/05 05:27
linux-6.1 WARNING in btrfs_quota_enable -1 1 346d 346d 0/3 auto-obsoleted due to no activity on 2026/02/06 00:31
linux-4.19 WARNING in btrfs_quota_enable btrfs -1 syz, C error 4 1323d 1395d 0/1 upstream: reported C repro on 2022/12/15 10:06

Sample crash report:
loop0: detected capacity change from 0 to 32768
BTRFS: device fsid 395ef67a-297e-477c-816d-cd80a5b93e5d devid 1 transid 8 /dev/loop0 (7:0) scanned by syz.0.0 (5317)
BTRFS info (device loop0): first mount of filesystem 395ef67a-297e-477c-816d-cd80a5b93e5d
BTRFS info (device loop0): using sha256 checksum algorithm
BTRFS info (device loop0): rebuilding free space tree
BTRFS info (device loop0): enabling ssd optimizations
BTRFS info (device loop0): using spread ssd allocation scheme
BTRFS info (device loop0): turning on async discard
BTRFS info (device loop0): enabling free space tree
BTRFS info (device loop0): force clearing of disk cache
------------[ cut here ]------------
btrfs_abort_should_print_stack(__error)
WARNING: fs/btrfs/qgroup.c:1077 at btrfs_quota_enable+0x1acf/0x1e20 fs/btrfs/qgroup.c:1077, CPU#0: syz.0.0/5317
Modules linked in:
CPU: 0 UID: 0 PID: 5317 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 04/01/2014
RIP: 0010:btrfs_quota_enable+0x1acf/0x1e20 fs/btrfs/qgroup.c:1077
Code: 08 00 00 00 4c 89 e7 e8 bf a2 01 fe e9 3c e7 ff ff e8 65 83 b1 07 e8 30 1f 8f fd eb 10 e8 29 1f 8f fd eb 09 e8 22 1f 8f fd 90 <0f> 0b 90 4c 8b 64 24 20 44 89 e1 f7 d9 e9 eb f9 ff ff 44 89 f7 48
RSP: 0018:ffffc9000e52fc80 EFLAGS: 00010283
RAX: ffffffff8439012e RBX: ffffffffffffffe4 RCX: 0000000000100000
RDX: ffffc9000f6a1000 RSI: 0000000000001175 RDI: 0000000000001176
RBP: ffffc9000e52fe70 R08: ffff88803d60a580 R09: 0000000000000003
R10: 00000000fffffffb R11: 0000000000000002 R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888053f1da00 R15: ffffc9000e52fd90
FS:  00007f8202bcd6c0(0000) GS:ffff88808b0b4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8202013300 CR3: 000000001375a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 btrfs_ioctl_quota_ctl+0x186/0x1f0 fs/btrfs/ioctl.c:3581
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8201d9e199
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:00007f8202bccfe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8202025fa0 RCX: 00007f8201d9e199
RDX: 00002000000000c0 RSI: 00000000c0109428 RDI: 0000000000000004
RBP: 00007f8201e35888 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8202026038 R14: 00007f8202025fa0 R15: 00007ffc432938d8
 </TASK>

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/08 03:31 upstream 7b63ef2d55f2 4f6a9fcf .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/10/06 08:57 upstream 2c3418fffa9d f7710056 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/10/04 07:04 upstream a74306e2e676 57bbd979 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/10/02 04:30 upstream d24e8ac715de 6d32eb1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/10/02 03:28 upstream d24e8ac715de 6d32eb1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/10/02 03:26 upstream d24e8ac715de 6d32eb1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/09/21 14:26 upstream 93f51579e7df 853b104b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/08/21 15:39 upstream 818bebeb63dd 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/08/21 15:39 upstream 818bebeb63dd 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
2026/08/21 15:38 upstream 818bebeb63dd 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in btrfs_quota_enable
* Struck through repros no longer work on HEAD.