syzbot
general protection fault in configfs_symlink
Status:
premoderation: reported on 2026/08/11 15:49
Reported-by: syzbot+9317bd15b43b72183e0e@syzkaller.appspotmail.com
First crash: 3d09h, last: 3d09h
Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f]
CPU: 1 PID: 1751 Comm: syz.2.428 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:create_link fs/configfs/symlink.c:83 [inline]
RIP: 0010:configfs_symlink+0x5e0/0x1320 fs/configfs/symlink.c:205
Code: 24 40 48 83 c3 48 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ee 39 d6 ff 48 8b 1b 48 83 c3 78 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 d1 39 d6 ff 4c 8b 23 4c 89 e7 e8
RSP: 0000:ffffc900014dfce0 EFLAGS: 00010206
RAX: 000000000000000f RBX: 0000000000000078 RCX: ffffffff84810592
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc900014dfc60
RBP: ffffc900014dfe18 R08: ffffc900014dfc67 R09: 1ffff9200029bf8c
R10: dffffc0000000000 R11: fffff5200029bf8d R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8558ef08 R15: ffff8881190b2200
FS: 00007f54cf2d86c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faebd5c1000 CR3: 000000012f754000 CR4: 00000000003526a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vfs_symlink+0x339/0x4c0 fs/namei.c:4107
do_symlinkat+0x10e/0x3d0 fs/namei.c:4134
__do_sys_symlink fs/namei.c:4153 [inline]
__se_sys_symlink fs/namei.c:4151 [inline]
__x64_sys_symlink+0x60/0x70 fs/namei.c:4151
do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f54d08a00d9
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:00007f54cf2d8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 00007f54d0b28090 RCX: 00007f54d08a00d9
RDX: 0000000000000000 RSI: 0000200000000940 RDI: 0000200000000900
RBP: 00007f54d0937024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f54d0b28128 R14: 00007f54d0b28090 R15: 00007ffc7b5a4318
Modules linked in:
---[ end trace 02d2fa0da63f2159 ]---
RIP: 0010:create_link fs/configfs/symlink.c:83 [inline]
RIP: 0010:configfs_symlink+0x5e0/0x1320 fs/configfs/symlink.c:205
Code: 24 40 48 83 c3 48 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ee 39 d6 ff 48 8b 1b 48 83 c3 78 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 d1 39 d6 ff 4c 8b 23 4c 89 e7 e8
RSP: 0000:ffffc900014dfce0 EFLAGS: 00010206
RAX: 000000000000000f RBX: 0000000000000078 RCX: ffffffff84810592
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc900014dfc60
RBP: ffffc900014dfe18 R08: ffffc900014dfc67 R09: 1ffff9200029bf8c
R10: dffffc0000000000 R11: fffff5200029bf8d R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8558ef08 R15: ffff8881190b2200
FS: 00007f54cf2d86c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2e24a1 CR3: 000000012f754000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 24 40 and $0x40,%al
2: 48 83 c3 48 add $0x48,%rbx
6: 48 89 d8 mov %rbx,%rax
9: 48 c1 e8 03 shr $0x3,%rax
d: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
12: 74 08 je 0x1c
14: 48 89 df mov %rbx,%rdi
17: e8 ee 39 d6 ff call 0xffd63a0a
1c: 48 8b 1b mov (%rbx),%rbx
1f: 48 83 c3 78 add $0x78,%rbx
23: 48 89 d8 mov %rbx,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 48 89 df mov %rbx,%rdi
34: e8 d1 39 d6 ff call 0xffd63a0a
39: 4c 8b 23 mov (%rbx),%r12
3c: 4c 89 e7 mov %r12,%rdi
3f: e8 .byte 0xe8
* Struck through repros no longer work on HEAD.