syzbot


general protection fault in nsim_fib_event_work

Status: moderation: reported on 2025/05/09 20:00
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+82d048181b547233d2a9@syzkaller.appspotmail.com
First crash: 1d04h, last: 11h01m

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 1 UID: 0 PID: 58 Comm: kworker/1:1 Not tainted 6.15.0-rc5-syzkaller-00204-g0e1329d4045c #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
Workqueue: events nsim_fib_event_work
RIP: 0010:nsim_fib6_rt_create drivers/net/netdevsim/fib.c:551 [inline]
RIP: 0010:nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
RIP: 0010:nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
RIP: 0010:nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
RIP: 0010:nsim_fib_event_work+0x183b/0x2e80 drivers/net/netdevsim/fib.c:1493
Code: 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 e6 11 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 2e 48 8d 7d 10 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e cb 11 00 00 49 8d 46 60 8b 6d
RSP: 0018:ffffc90000affb10 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88803129e980 RCX: ffff888050f5e0a0
RDX: 0000000000000002 RSI: ffffffff87129e98 RDI: 0000000000000010
RBP: 0000000000000000 R08: ffffffff911324ce R09: ffff88816d4b40b0
R10: 0000000000000003 R11: 0000000000002bb0 R12: ffff88804f9a6be0
R13: 0000000000000001 R14: ffff8880428dc000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880d6ae1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000004ca000 CR3: 00000000599a9000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nsim_fib6_rt_create drivers/net/netdevsim/fib.c:551 [inline]
RIP: 0010:nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
RIP: 0010:nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
RIP: 0010:nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
RIP: 0010:nsim_fib_event_work+0x183b/0x2e80 drivers/net/netdevsim/fib.c:1493
Code: 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 e6 11 00 00 48 b8 00 00 00 00 00 fc ff df 49 8b 2e 48 8d 7d 10 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e cb 11 00 00 49 8d 46 60 8b 6d
RSP: 0018:ffffc90000affb10 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88803129e980 RCX: ffff888050f5e0a0
RDX: 0000000000000002 RSI: ffffffff87129e98 RDI: 0000000000000010
RBP: 0000000000000000 R08: ffffffff911324ce R09: ffff88816d4b40b0
R10: 0000000000000003 R11: 0000000000002bb0 R12: ffff88804f9a6be0
R13: 0000000000000001 R14: ffff8880428dc000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880d6ae1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005624703c6b00 CR3: 000000000e180000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	48 c1 ea 03          	shr    $0x3,%rdx
   4:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   8:	0f 85 e6 11 00 00    	jne    0x11f4
   e:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  15:	fc ff df
  18:	49 8b 2e             	mov    (%r14),%rbp
  1b:	48 8d 7d 10          	lea    0x10(%rbp),%rdi
  1f:	48 89 fa             	mov    %rdi,%rdx
  22:	48 c1 ea 03          	shr    $0x3,%rdx
* 26:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2a:	84 c0                	test   %al,%al
  2c:	74 08                	je     0x36
  2e:	3c 03                	cmp    $0x3,%al
  30:	0f 8e cb 11 00 00    	jle    0x1201
  36:	49 8d 46 60          	lea    0x60(%r14),%rax
  3a:	8b                   	.byte 0x8b
  3b:	6d                   	insl   (%dx),%es:(%rdi)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/10 04:01 upstream 0e1329d4045c 77908e5f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in nsim_fib_event_work
2025/05/09 10:54 upstream 9c69f8884904 43803998 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in nsim_fib_event_work
* Struck through repros no longer work on HEAD.