syzbot


general protection fault in step_into

Status: upstream: reported C repro on 2025/09/14 20:10
Reported-by: syzbot+f3a1ef61c7e1d78a2fb6@syzkaller.appspotmail.com
First crash: 1d11h, last: 3h39m
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 general protection fault in step_into origin:lts-only 11 C done 287 1d04h 520d 0/3 upstream: reported C repro on 2024/04/13 08:21
upstream general protection fault in step_into fs 2 1 1843d 1839d 0/29 auto-closed as invalid on 2020/11/28 01:59
android-5-10 general protection fault in step_into 2 C done 247 6d08h 855d 0/2 upstream: reported C repro on 2023/05/14 14:12
linux-6.1 KASAN: null-ptr-deref Read in step_into origin:lts-only 11 C inconclusive 68 9d05h 527d 0/3 upstream: reported C repro on 2024/04/06 11:08
android-5-15 general protection fault in step_into origin:downstream 2 C done 96 1d04h 855d 0/2 upstream: reported C repro on 2023/05/14 14:01
android-6-1 general protection fault in step_into origin:downstream 2 C done 80 3d19h 855d 0/2 upstream: reported C repro on 2023/05/14 14:12
android-6-12 general protection fault in step_into origin:downstream 2 C 18 1d15h 77d 0/1 premoderation: reported C repro on 2025/06/30 23:58
upstream BUG: unable to handle kernel paging request in step_into ntfs3 11 C error done 5 619d 985d 0/29 auto-obsoleted due to no activity on 2024/05/25 15:27

Sample crash report:
ntfs: (device loop0): ntfs_ucstonls(): Unicode name contains characters that cannot be converted to character set iso8859-2.  You might want to try to use the mount option nls=utf8.
ntfs: (device loop0): ntfs_filldir(): Skipping unrepresentable inode 0x4.
ntfs: (device loop0): ntfs_lookup(): ntfs_lookup_ino_by_name() failed with error code -24.
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: 5907 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:traverse_mounts fs/namei.c:1435 [inline]
RIP: 0010:handle_mounts fs/namei.c:1547 [inline]
RIP: 0010:step_into+0x121/0xf10 fs/namei.c:1840
Code: 74 24 08 c6 44 24 7f 00 43 0f b6 04 3c 84 c0 4d 89 fd 0f 85 f5 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 f4 0b 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc90003387ac0 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffffc90003387ca0 RCX: ffff888023333c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003387bc8 R08: ffff88805dce4e57 R09: 1ffff1100bb9c9ca
R10: dffffc0000000000 R11: ffffed100bb9c9cb R12: 1ffff92000670f9b
R13: dffffc0000000000 R14: 0000000000000080 R15: 0000000000000018
FS:  000055557611a500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc76b47c08 CR3: 000000005e901000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 lookup_last fs/namei.c:2459 [inline]
 path_lookupat+0x169/0x440 fs/namei.c:2483
 filename_lookup+0x1f4/0x510 fs/namei.c:2512
 user_path_at_empty+0x42/0x60 fs/namei.c:2909
 user_path_at include/linux/namei.h:57 [inline]
 ksys_umount fs/namespace.c:1912 [inline]
 __do_sys_umount fs/namespace.c:1920 [inline]
 __se_sys_umount fs/namespace.c:1918 [inline]
 __x64_sys_umount+0xf5/0x170 fs/namespace.c:1918
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa77078fed7
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 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 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc76b483b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa77078fed7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc76b48470
RBP: 00007ffc76b48470 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc76b49560
R13: 00007fa770811c05 R14: 000055557611a4a8 R15: 00007ffc76b4b720
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:traverse_mounts fs/namei.c:1435 [inline]
RIP: 0010:handle_mounts fs/namei.c:1547 [inline]
RIP: 0010:step_into+0x121/0xf10 fs/namei.c:1840
Code: 74 24 08 c6 44 24 7f 00 43 0f b6 04 3c 84 c0 4d 89 fd 0f 85 f5 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 f4 0b 00 00 45 8b 3f 44 89 fe 81 e6 00
RSP: 0018:ffffc90003387ac0 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffffc90003387ca0 RCX: ffff888023333c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003387bc8 R08: ffff88805dce4e57 R09: 1ffff1100bb9c9ca
R10: dffffc0000000000 R11: ffffed100bb9c9cb R12: 1ffff92000670f9b
R13: dffffc0000000000 R14: 0000000000000080 R15: 0000000000000018
FS:  000055557611a500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc76b47c08 CR3: 000000005e901000 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 f5 0b 00 00    	jne    0xc0d
  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 f4 0b 00 00    	jne    0xc2b
  37:	45 8b 3f             	mov    (%r15),%r15d
  3a:	44 89 fe             	mov    %r15d,%esi
  3d:	81                   	.byte 0x81
  3e:	e6 00                	out    %al,$0x0

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/16 04:14 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/16 02:02 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/15 21:18 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/15 16:41 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/15 13:31 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/15 09:42 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/15 00:40 linux-6.6.y 60a9e718726f e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-6-kasan general protection fault in step_into
2025/09/14 20:09 linux-6.6.y 60a9e718726f e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in step_into
* Struck through repros no longer work on HEAD.