syzbot


general protection fault in can_rx_unregister (2)

Status: moderation: reported on 2026/04/16 20:38
Subsystems: can
[Documentation on labels]
Reported-by: syzbot+0b0900adc47a4f6f9f9a@syzkaller.appspotmail.com
First crash: 5d09h, last: 5d09h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in can_rx_unregister can 2 1 182d 178d 0/29 auto-obsoleted due to no activity on 2026/01/25 13:05

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 0 UID: 0 PID: 6472 Comm: syz.1.124 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:can_rx_unregister+0x250/0x6d0 net/can/af_can.c:537
Code: 54 24 18 48 8d 84 24 b8 00 00 00 48 8d 74 24 78 48 8d 78 b0 e8 d1 ee ff ff 48 ba 00 00 00 00 00 fc ff df 48 89 c1 48 c1 e9 03 <80> 3c 11 00 0f 85 4f 04 00 00 48 8b 18 44 8b 64 24 68 44 8b 7c 24
RSP: 0018:ffffc900037bfb80 EFLAGS: 00010202
RAX: 0000000000000058 RBX: 0000000000000000 RCX: 000000000000000b
RDX: dffffc0000000000 RSI: ffffffff8a801db9 RDI: ffff888032190000
RBP: 0000000000000000 R08: 0000000000000005 R09: 00000000c00007ff
R10: 00000000c00007ff R11: 0000000000000000 R12: ffff888022db0578
R13: ffff888028a64000 R14: 1ffff920006f7f77 R15: 00000000c00007ff
FS:  0000555577445500(0000) GS:ffff8880d6338000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb862b4da08 CR3: 0000000064937000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 isotp_release+0x899/0xaf0 net/can/isotp.c:1231
 __sock_release+0xb3/0x260 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x100/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0f599c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc8a8669c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc8a866ab0 RCX: 00007fd0f599c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000011d11 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2ea20000 R11: 0000000000000246 R12: 00007ffc8a866af0
R13: 00007fd0f5c15fac R14: 0000000000011d8f R15: 00007fd0f5c15fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:can_rx_unregister+0x250/0x6d0 net/can/af_can.c:537
Code: 54 24 18 48 8d 84 24 b8 00 00 00 48 8d 74 24 78 48 8d 78 b0 e8 d1 ee ff ff 48 ba 00 00 00 00 00 fc ff df 48 89 c1 48 c1 e9 03 <80> 3c 11 00 0f 85 4f 04 00 00 48 8b 18 44 8b 64 24 68 44 8b 7c 24
RSP: 0018:ffffc900037bfb80 EFLAGS: 00010202
RAX: 0000000000000058 RBX: 0000000000000000 RCX: 000000000000000b
RDX: dffffc0000000000 RSI: ffffffff8a801db9 RDI: ffff888032190000
RBP: 0000000000000000 R08: 0000000000000005 R09: 00000000c00007ff
R10: 00000000c00007ff R11: 0000000000000000 R12: ffff888022db0578
R13: ffff888028a64000 R14: 1ffff920006f7f77 R15: 00000000c00007ff
FS:  0000555577445500(0000) GS:ffff8880d6338000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb862b4da08 CR3: 0000000064937000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	54                   	push   %rsp
   1:	24 18                	and    $0x18,%al
   3:	48 8d 84 24 b8 00 00 	lea    0xb8(%rsp),%rax
   a:	00
   b:	48 8d 74 24 78       	lea    0x78(%rsp),%rsi
  10:	48 8d 78 b0          	lea    -0x50(%rax),%rdi
  14:	e8 d1 ee ff ff       	call   0xffffeeea
  19:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  20:	fc ff df
  23:	48 89 c1             	mov    %rax,%rcx
  26:	48 c1 e9 03          	shr    $0x3,%rcx
* 2a:	80 3c 11 00          	cmpb   $0x0,(%rcx,%rdx,1) <-- trapping instruction
  2e:	0f 85 4f 04 00 00    	jne    0x483
  34:	48 8b 18             	mov    (%rax),%rbx
  37:	44 8b 64 24 68       	mov    0x68(%rsp),%r12d
  3c:	44                   	rex.R
  3d:	8b                   	.byte 0x8b
  3e:	7c 24                	jl     0x64

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/12 20:29 upstream f5459048c38a 38c8e246 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in can_rx_unregister
* Struck through repros no longer work on HEAD.