linux-kernel - [syzbot] [net?] [ext4?] general protection fault in clip

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <68556f59.a00a0220.137b3.004e.GAE@google.com>
Date: Fri, 20 Jun 2025 07:25:29 -0700
From: syzbot <syzbot+1316233c4c6803382a8b@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, horms@...nel.org, 
	kuba@...nel.org, linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org, 
	netdev@...r.kernel.org, pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] [ext4?] general protection fault in clip_push

Hello,

syzbot found the following issue on:

HEAD commit:    41687a5c6f8b Merge tag 'spi-fix-v6.16-rc2' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12ca5370580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d11f52d3049c3790
dashboard link: https://syzkaller.appspot.com/bug?extid=1316233c4c6803382a8b
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17365d0c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11cff5d4580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-41687a5c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c889133baca6/vmlinux-41687a5c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/288c0c860dbf/bzImage-41687a5c.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/ad66cd154f6a/mount_4.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=10818182580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1316233c4c6803382a8b@...kaller.appspotmail.com

EXT4-fs: Ignoring removed oldalloc option
EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
Oops: general protection fault, probably for non-canonical address 0xdffffc000000001c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x00000000000000e0-0x00000000000000e7]
CPU: 0 UID: 0 PID: 5312 Comm: syz-executor180 Not tainted 6.16.0-rc2-syzkaller-00162-g41687a5c6f8b #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:clip_push+0x6dd/0x760 net/atm/clip.c:197
Code: 20 8d aa 8c e8 e4 f6 5b fa 48 83 3d bc 23 64 0f 00 0f 85 94 f9 ff ff e8 a1 32 27 f7 48 8d bb e0 00 00 00 48 89 f8 48 c1 e8 03 <0f> b6 04 28 84 c0 75 3c 8b ab e0 00 00 00 49 8d bd 40 01 00 00 be
RSP: 0018:ffffc9000d4e7898 EFLAGS: 00010202
RAX: 000000000000001c RBX: 0000000000000000 RCX: ffff888000f3c880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000e0
RBP: dffffc0000000000 R08: ffffffff8fa110f7 R09: 1ffffffff1f4221e
R10: dffffc0000000000 R11: ffffffff8a9922e0 R12: ffffffff8a9922e0
R13: ffff888031799000 R14: ffff8880429ce180 R15: ffff888031799578
FS:  0000000000000000(0000) GS:ffff88808d251000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f074213de58 CR3: 000000003f358000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vcc_destroy_socket net/atm/common.c:183 [inline]
 vcc_release+0x15a/0x460 net/atm/common.c:205
 __sock_release net/socket.c:647 [inline]
 sock_close+0xc0/0x240 net/socket.c:1391
 __fput+0x44c/0xa70 fs/file_table.c:465
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6ad/0x22e0 kernel/exit.c:955
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1104
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f07420ea849
Code: Unable to access opcode bytes at 0x7f07420ea81f.
RSP: 002b:00007f074209f198 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f07421716c8 RCX: 00007f07420ea849
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f07421716cc
RBP: 00007f07421716c0 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 65732f636f72702f R11: 0000000000000246 R12: 00007f074213e56c
R13: 00007f074209f1a0 R14: 0031656c69662f2e R15: 0000200000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:clip_push+0x6dd/0x760 net/atm/clip.c:197
Code: 20 8d aa 8c e8 e4 f6 5b fa 48 83 3d bc 23 64 0f 00 0f 85 94 f9 ff ff e8 a1 32 27 f7 48 8d bb e0 00 00 00 48 89 f8 48 c1 e8 03 <0f> b6 04 28 84 c0 75 3c 8b ab e0 00 00 00 49 8d bd 40 01 00 00 be
RSP: 0018:ffffc9000d4e7898 EFLAGS: 00010202
RAX: 000000000000001c RBX: 0000000000000000 RCX: ffff888000f3c880
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000e0
RBP: dffffc0000000000 R08: ffffffff8fa110f7 R09: 1ffffffff1f4221e
R10: dffffc0000000000 R11: ffffffff8a9922e0 R12: ffffffff8a9922e0
R13: ffff888031799000 R14: ffff8880429ce180 R15: ffff888031799578
FS:  0000000000000000(0000) GS:ffff88808d251000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f074213de58 CR3: 00000000403da000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	20 8d aa 8c e8 e4    	and    %cl,-0x1b177356(%rbp)
   6:	f6 5b fa             	negb   -0x6(%rbx)
   9:	48 83 3d bc 23 64 0f 	cmpq   $0x0,0xf6423bc(%rip)        # 0xf6423cd
  10:	00
  11:	0f 85 94 f9 ff ff    	jne    0xfffff9ab
  17:	e8 a1 32 27 f7       	call   0xf72732bd
  1c:	48 8d bb e0 00 00 00 	lea    0xe0(%rbx),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	75 3c                	jne    0x6e
  32:	8b ab e0 00 00 00    	mov    0xe0(%rbx),%ebp
  38:	49 8d bd 40 01 00 00 	lea    0x140(%r13),%rdi
  3f:	be                   	.byte 0xbe


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup