[syzbot] [lsm?] general protection fault in smack_inode_permission (4)

syzbot syzbot+fc1d5d9a7ebabbc27458 at syzkaller.appspotmail.com
Sun Oct 4 02:47:26 UTC 2026


Hello,

syzbot found the following issue on:

HEAD commit:    ce1e0223d8ad Merge tag 'devicetree-fixes-for-7.3-2' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12555b15580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=718e346eb0b8f38
dashboard link: https://syzkaller.appspot.com/bug?extid=fc1d5d9a7ebabbc27458
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4167e1ad25c1/disk-ce1e0223.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a0a74c8dec59/vmlinux-ce1e0223.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f6caa72edd70/bzImage-ce1e0223.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fc1d5d9a7ebabbc27458 at syzkaller.appspotmail.com

ERROR: (device loop4): jfs_readdir: JFS:Dtree error: ino = 2, bn=0, index = 3
ERROR: (device loop4): jfs_readdir: JFS:Dtree error: ino = 2, bn=0, index = 5
ERROR: (device loop4): jfs_readdir: JFS:Dtree error: ino = 2, bn=0, index = 6
Oops: general protection fault, probably for non-canonical address 0xdffffc018bd1a30b: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000c5e8d1858-0x0000000c5e8d185f]
CPU: 1 UID: 0 PID: 5607 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:smk_of_inode security/smack/smack.h:411 [inline]
RIP: 0010:smack_inode_permission+0x265/0x320 security/smack/smack_lsm.c:1260
Code: 83 c5 38 4c 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8 1d 99 ab fd 44 8b 3d 66 df 2c 09 4d 03 7d 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ff e8 fd 98 ab fd 49 8b 3f 44 89 f6 48 8d
RSP: 0018:ffffc900058c7920 EFLAGS: 00010202
RAX: 000000018bd1a30b RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900058c7978
RBP: ffffc900058c7a28 R08: ffffc900058c79af R09: 0000000000000000
R10: ffffc900058c7980 R11: fffff52000b18f36 R12: 1ffff92000b18f28
R13: ffff888040368e20 R14: 0000000000000001 R15: 0000000c5e8d1858
FS:  0000555564dc7500(0000) GS:ffff888125cc3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc8c0efcf0 CR3: 000000002ad9e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 security_inode_permission+0xf4/0x2e0 security/security.c:1842
 lookup_inode_permission_may_exec fs/namei.c:696 [inline]
 may_lookup fs/namei.c:1961 [inline]
 link_path_walk+0xc30/0x1910 fs/namei.c:2604
 path_lookupat+0xe4/0x8c0 fs/namei.c:2812
 filename_lookup+0x265/0x5d0 fs/namei.c:2842
 user_path_at+0x40/0x160 fs/namei.c:3641
 ksys_umount fs/namespace.c:2067 [inline]
 __do_sys_umount fs/namespace.c:2075 [inline]
 __se_sys_umount fs/namespace.c:2073 [inline]
 __x64_sys_umount+0xf6/0x170 fs/namespace.c:2073
 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: 0033:0x7fabd8aaf397
Code: a2 c7 05 5c 43 25 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:00007ffc8c0f0348 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007fabd8b444bb RCX: 00007fabd8aaf397
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc8c0f0400
RBP: 00007ffc8c0f0400 R08: 00007ffc8c0f1400 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc8c0f14f0
R13: 00007fabd8b444bb R14: 00000000000345b3 R15: 00007ffc8c0f25c0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:smk_of_inode security/smack/smack.h:411 [inline]
RIP: 0010:smack_inode_permission+0x265/0x320 security/smack/smack_lsm.c:1260
Code: 83 c5 38 4c 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8 1d 99 ab fd 44 8b 3d 66 df 2c 09 4d 03 7d 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 ff e8 fd 98 ab fd 49 8b 3f 44 89 f6 48 8d
RSP: 0018:ffffc900058c7920 EFLAGS: 00010202
RAX: 000000018bd1a30b RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900058c7978
RBP: ffffc900058c7a28 R08: ffffc900058c79af R09: 0000000000000000
R10: ffffc900058c7980 R11: fffff52000b18f36 R12: 1ffff92000b18f28
R13: ffff888040368e20 R14: 0000000000000001 R15: 0000000c5e8d1858
FS:  0000555564dc7500(0000) GS:ffff888125cc3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc8c0efcf0 CR3: 000000002ad9e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	83 c5 38             	add    $0x38,%ebp
   3:	4c 89 e8             	mov    %r13,%rax
   6:	48 c1 e8 03          	shr    $0x3,%rax
   a:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1)
   e:	74 08                	je     0x18
  10:	4c 89 ef             	mov    %r13,%rdi
  13:	e8 1d 99 ab fd       	call   0xfdab9935
  18:	44 8b 3d 66 df 2c 09 	mov    0x92cdf66(%rip),%r15d        # 0x92cdf85
  1f:	4d 03 7d 00          	add    0x0(%r13),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ff             	mov    %r15,%rdi
  33:	e8 fd 98 ab fd       	call   0xfdab9935
  38:	49 8b 3f             	mov    (%r15),%rdi
  3b:	44 89 f6             	mov    %r14d,%esi
  3e:	48                   	rex.W
  3f:	8d                   	.byte 0x8d


---
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