syzbot
general protection fault in gfs2_quota_lock
Status:
upstream: reported C repro on 2026/09/01 23:06
Subsystems:
gfs2
Labels:
prio:high
[Documentation on labels]
Reported-by: syzbot+d84e35a320d14f8c270a@syzkaller.appspotmail.com
First crash: 1d07h, last: 21h51m
Sample crash report:
capability: warning: `syz-executor311' uses deprecated v2 capabilities in a way that may be insecure
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000020: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000100-0x0000000000000107]
CPU: 1 UID: 0 PID: 5636 Comm: syz-executor311 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:gfs2_quota_lock+0x103/0x7b0 fs/gfs2/quota.c:1105
Code: 00 00 4d 89 fd 49 c1 ed 03 41 80 7c 1d 00 00 74 08 4c 89 ff e8 1e fd e7 fd 49 8b 3f 48 8d 87 00 01 00 00 48 89 c1 48 c1 e9 03 <0f> b6 0c 19 84 c9 0f 85 c9 05 00 00 8b b7 00 01 00 00 ba 08 00 00
RSP: 0018:ffffc90003bcf8d0 EFLAGS: 00010202
RAX: 0000000000000100 RBX: dffffc0000000000 RCX: 0000000000000020
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff907a487f R09: 1ffffffff20f490f
R10: dffffc0000000000 R11: fffffbfff20f4910 R12: ffff888012189320
R13: 1ffff110024312f9 R14: 00000000ffffffff R15: ffff8880121897c8
FS: 000055558edf6400(0000) GS:ffff888124dcd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006a9ee0 CR3: 0000000073f60000 CR4: 00000000003526f0
Call Trace:
<TASK>
gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
do_grow fs/gfs2/bmap.c:2117 [inline]
gfs2_setattr_size+0x9df/0x1270 fs/gfs2/bmap.c:2198
gfs2_setattr+0x269/0x430 fs/gfs2/inode.c:2138
notify_change+0xbba/0xea0 fs/attr.c:556
do_truncate+0x1c2/0x250 fs/open.c:68
vfs_truncate+0x4b4/0x540 fs/open.c:118
ksys_truncate+0xf3/0x1c0 fs/open.c:142
__do_sys_truncate fs/open.c:154 [inline]
__se_sys_truncate fs/open.c:152 [inline]
__x64_sys_truncate+0x5b/0x70 fs/open.c:152
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: 0033:0x7f49688f2409
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4cc3da68 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f49688f2409
RDX: 00007f49688f2409 RSI: 000000000008fff5 RDI: 0000200000000180
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd4cc3db98
R13: 0000000000000002 R14: 00007f49689b3c80 R15: 0000000000000002
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:gfs2_quota_lock+0x103/0x7b0 fs/gfs2/quota.c:1105
Code: 00 00 4d 89 fd 49 c1 ed 03 41 80 7c 1d 00 00 74 08 4c 89 ff e8 1e fd e7 fd 49 8b 3f 48 8d 87 00 01 00 00 48 89 c1 48 c1 e9 03 <0f> b6 0c 19 84 c9 0f 85 c9 05 00 00 8b b7 00 01 00 00 ba 08 00 00
RSP: 0018:ffffc90003bcf8d0 EFLAGS: 00010202
RAX: 0000000000000100 RBX: dffffc0000000000 RCX: 0000000000000020
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff907a487f R09: 1ffffffff20f490f
R10: dffffc0000000000 R11: fffffbfff20f4910 R12: ffff888012189320
R13: 1ffff110024312f9 R14: 00000000ffffffff R15: ffff8880121897c8
FS: 000055558edf6400(0000) GS:ffff888124dcd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006a9ee0 CR3: 0000000073f60000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 4d 89 fd mov %r15,%r13
5: 49 c1 ed 03 shr $0x3,%r13
9: 41 80 7c 1d 00 00 cmpb $0x0,0x0(%r13,%rbx,1)
f: 74 08 je 0x19
11: 4c 89 ff mov %r15,%rdi
14: e8 1e fd e7 fd call 0xfde7fd37
19: 49 8b 3f mov (%r15),%rdi
1c: 48 8d 87 00 01 00 00 lea 0x100(%rdi),%rax
23: 48 89 c1 mov %rax,%rcx
26: 48 c1 e9 03 shr $0x3,%rcx
* 2a: 0f b6 0c 19 movzbl (%rcx,%rbx,1),%ecx <-- trapping instruction
2e: 84 c9 test %cl,%cl
30: 0f 85 c9 05 00 00 jne 0x5ff
36: 8b b7 00 01 00 00 mov 0x100(%rdi),%esi
3c: ba .byte 0xba
3d: 08 00 or %al,(%rax)
* Struck through repros no longer work on HEAD.