syzbot


general protection fault in lec_arp_clear_vccs

Status: upstream: reported on 2025/09/16 12:39
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+72e3ea390c305de0e259@syzkaller.appspotmail.com
First crash: 4d08h, last: 4d08h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] general protection fault in lec_arp_clear_vccs 0 (1) 2025/09/16 12:39

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 27966 Comm: syz.1.7437 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:lec_arp_clear_vccs+0xad/0x380 net/atm/lec.c:1263
Code: e8 03 80 3c 28 00 74 08 4c 89 e7 e8 9d e0 76 f7 4c 89 74 24 18 49 8b 2c 24 4c 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ef e8 75 e0 76 f7 4d 8b 75 00 4d 8d a7 18
RSP: 0018:ffffc9001c217bd0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880528ad400 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff8be33be0 RDI: ffff8880528ad400
RBP: ffff88802e2c2000 R08: ffffffff8e8e2db3 R09: 1ffffffff1d1c5b6
R10: dffffc0000000000 R11: fffffbfff1d1c5b7 R12: ffff88807df10638
R13: 0000000000000000 R14: ffff8880528ad430 R15: ffff88807df10000
FS:  000055555dcab500(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2733b056c0 CR3: 000000007e312000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lec_vcc_close net/atm/lec.c:2183 [inline]
 lec_push+0x3cb/0x1860 net/atm/lec.c:594
 vcc_destroy_socket net/atm/common.c:183 [inline]
 vcc_release+0x157/0x460 net/atm/common.c:205
 svc_release+0x6b/0xb0 net/atm/svc.c:95
 __sock_release net/socket.c:649 [inline]
 sock_close+0xc3/0x240 net/socket.c:1439
 __fput+0x449/0xa70 fs/file_table.c:468
 task_work_run+0x1d1/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f114b78eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff6f7d2028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f114b9d7da0 RCX: 00007f114b78eba9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f114b9d7da0 R08: 0000000000000000 R09: 0000000d6f7d231f
R10: 000000000003fd58 R11: 0000000000000246 R12: 00000000000a243d
R13: 00007fff6f7d2120 R14: ffffffffffffffff R15: 00007fff6f7d2140
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:lec_arp_clear_vccs+0xad/0x380 net/atm/lec.c:1263
Code: e8 03 80 3c 28 00 74 08 4c 89 e7 e8 9d e0 76 f7 4c 89 74 24 18 49 8b 2c 24 4c 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ef e8 75 e0 76 f7 4d 8b 75 00 4d 8d a7 18
RSP: 0018:ffffc9001c217bd0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8880528ad400 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffffffff8be33be0 RDI: ffff8880528ad400
RBP: ffff88802e2c2000 R08: ffffffff8e8e2db3 R09: 1ffffffff1d1c5b6
R10: dffffc0000000000 R11: fffffbfff1d1c5b7 R12: ffff88807df10638
R13: 0000000000000000 R14: ffff8880528ad430 R15: ffff88807df10000
FS:  000055555dcab500(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2733b056c0 CR3: 000000007e312000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	e8 03 80 3c 28       	call   0x283c8008
   5:	00 74 08 4c          	add    %dh,0x4c(%rax,%rcx,1)
   9:	89 e7                	mov    %esp,%edi
   b:	e8 9d e0 76 f7       	call   0xf776e0ad
  10:	4c 89 74 24 18       	mov    %r14,0x18(%rsp)
  15:	49 8b 2c 24          	mov    (%r12),%rbp
  19:	4c 89 e8             	mov    %r13,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ef             	mov    %r13,%rdi
  33:	e8 75 e0 76 f7       	call   0xf776e0ad
  38:	4d 8b 75 00          	mov    0x0(%r13),%r14
  3c:	4d                   	rex.WRB
  3d:	8d                   	.byte 0x8d
  3e:	a7                   	cmpsl  %es:(%rdi),%ds:(%rsi)
  3f:	18                   	.byte 0x18

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/12 10:41 net 2690cb089502 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce general protection fault in lec_arp_clear_vccs
* Struck through repros no longer work on HEAD.