syzbot
general protection fault in step_into
Status:
upstream: reported C repro on 2025/09/14 20:10
Bug presence:
origin:lts-only
[Documentation on labels]
Reported-by: syzbot+f3a1ef61c7e1d78a2fb6@syzkaller.appspotmail.com
First crash: 316d, last: 98d
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Bug presence (2)
| Date |
Name |
Commit |
Repro |
Result |
| 2025/09/19 |
linux-6.6.y (ToT) |
60a9e718726f |
C
|
[report] general protection fault in step_into
|
| 2025/09/19 |
upstream (ToT) |
097a6c336d00 |
C
|
Didn't crash |
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Fix bisection attempts (1)
| Created |
Duration |
User |
Patch |
Repo |
Result |
| 2025/11/18 23:58 |
1h46m
|
fix candidate
|
|
upstream |
OK
(0)
job log
|
Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 0 PID: 5875 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:traverse_mounts fs/namei.c:1443 [inline]
RIP: 0010:handle_mounts fs/namei.c:1555 [inline]
RIP: 0010:step_into+0x129/0xf20 fs/namei.c:1848
Code: 74 24 08 c6 44 24 7f 00 43 0f b6 04 3c 84 c0 4d 89 fd 0f 85 fd 0b 00 00 45 8b 36 4c 8b bc 24 a8 00 00 00 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 fc 0b 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc90003057ac0 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffffc90003057ca0 RCX: ffff888027113c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003057bc8 R08: ffff88805dc5ded7 R09: 1ffff1100bb8bbda
R10: dffffc0000000000 R11: ffffed100bb8bbdb R12: 1ffff9200060af9b
R13: dffffc0000000000 R14: 0000000000000080 R15: 0000000000000018
FS: 0000555570e5b500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555570e86aa8 CR3: 000000002f2ba000 CR4: 00000000003506f0
Call Trace:
<TASK>
lookup_last fs/namei.c:2467 [inline]
path_lookupat+0x169/0x440 fs/namei.c:2491
filename_lookup+0x228/0x560 fs/namei.c:2520
user_path_at_empty+0x42/0x60 fs/namei.c:2917
user_path_at include/linux/namei.h:57 [inline]
ksys_umount fs/namespace.c:1921 [inline]
__do_sys_umount fs/namespace.c:1929 [inline]
__se_sys_umount fs/namespace.c:1927 [inline]
__x64_sys_umount+0xfd/0x180 fs/namespace.c:1927
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb1df39da57
Code: a2 c7 05 9c fc 24 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffcb192ba28 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb1df39da57
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcb192bae0
RBP: 00007ffcb192bae0 R08: 00007ffcb192cae0 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcb192cbd0
R13: 00007fb1df432048 R14: 0000555570e5b4e8 R15: 00007ffcb192ed90
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:traverse_mounts fs/namei.c:1443 [inline]
RIP: 0010:handle_mounts fs/namei.c:1555 [inline]
RIP: 0010:step_into+0x129/0xf20 fs/namei.c:1848
Code: 74 24 08 c6 44 24 7f 00 43 0f b6 04 3c 84 c0 4d 89 fd 0f 85 fd 0b 00 00 45 8b 36 4c 8b bc 24 a8 00 00 00 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 fc 0b 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc90003057ac0 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffffc90003057ca0 RCX: ffff888027113c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003057bc8 R08: ffff88805dc5ded7 R09: 1ffff1100bb8bbda
R10: dffffc0000000000 R11: ffffed100bb8bbdb R12: 1ffff9200060af9b
R13: dffffc0000000000 R14: 0000000000000080 R15: 0000000000000018
FS: 0000555570e5b500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f05eada1796 CR3: 000000002f2ba000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: 74 24 je 0x26
2: 08 c6 or %al,%dh
4: 44 24 7f rex.R and $0x7f,%al
7: 00 43 0f add %al,0xf(%rbx)
a: b6 04 mov $0x4,%dh
c: 3c 84 cmp $0x84,%al
e: c0 4d 89 fd rorb $0xfd,-0x77(%rbp)
12: 0f 85 fd 0b 00 00 jne 0xc15
18: 45 8b 36 mov (%r14),%r14d
1b: 4c 8b bc 24 a8 00 00 mov 0xa8(%rsp),%r15
22: 00
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 fc 0b 00 00 jne 0xc33
37: 45 8b 3f mov (%r15),%r15d
3a: 44 89 fe mov %r15d,%esi
3d: 81 .byte 0x81
3e: e6 00 out %al,$0x0
* Struck through repros no longer work on HEAD.