syzbot


divide error in netem_enqueue

Status: auto-closed as invalid on 2022/08/28 08:54
Reported-by: syzbot+f35528b5fd195a1193ec@syzkaller.appspotmail.com
First crash: 311d, last: 300d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream divide error in netem_enqueue C done done 332 235d 1248d 0/24 closed as invalid on 2022/11/15 21:20
android-5-10 divide error in netem_enqueue (2) 1 192d 192d 0/2 auto-obsoleted due to no activity on 2022/12/14 01:50
linux-4.19 divide error in netem_enqueue C error 55 66d 851d 0/1 upstream: reported C repro on 2020/11/25 15:52
linux-4.14 divide error in netem_enqueue C error 32 293d 1185d 0/1 upstream: reported C repro on 2019/12/26 23:17

Sample crash report:
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 12131 Comm: syz-executor.4 Not tainted 5.10.117-syzkaller-00813-g0974b8411a58 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:netem_enqueue+0x29e6/0x3900 net/sched/sch_netem.c:516
Code: 45 8b 75 70 4c 89 6c 24 28 49 83 c5 74 4c 89 e9 48 c1 e9 03 8a 14 31 84 d2 48 8b 5c 24 10 0f 85 32 08 00 00 45 2b 75 00 31 d2 <41> f7 f6 49 01 d4 4c 89 e0 48 c1 e8 03 8a 04 30 84 c0 0f 85 45 08
RSP: 0018:ffffc90000bf74c0 EFLAGS: 00010246
RAX: 00000000e568b28f RBX: ffff888111316800 RCX: 1ffff1102371edc6
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff88811b8f6e30
RBP: ffffc90000bf75f0 R08: ffffffff8249afaa R09: 0000000000000003
R10: fffff5200017edfd R11: 1ffff9200017edfc R12: ffff88811118f480
R13: ffff88811b8f6e34 R14: 0000000000000000 R15: 0000000000000020
FS:  00007f0f55af5700(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000240 CR3: 000000014ce23000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 netem_enqueue+0x12cb/0x3900 net/sched/sch_netem.c:483
 __dev_xmit_skb net/core/dev.c:3823 [inline]
 __dev_queue_xmit+0xdde/0x2bb0 net/core/dev.c:4136
 dev_queue_xmit+0x17/0x20 net/core/dev.c:4204
 packet_snd net/packet/af_packet.c:3022 [inline]
 packet_sendmsg+0x4cfc/0x6880 net/packet/af_packet.c:3054
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 __sys_sendto+0x541/0x700 net/socket.c:1982
 __do_sys_sendto net/socket.c:1994 [inline]
 __se_sys_sendto net/socket.c:1990 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:1990
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f0f5697f109
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0f55af5168 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0f56a91f60 RCX: 00007f0f5697f109
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f0f569d908d R08: 0000000020000240 R09: 0000000000000080
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffec938adcf R14: 00007f0f55af5300 R15: 0000000000022000
Modules linked in:
---[ end trace 5cae68ec3b858d3e ]---
RIP: 0010:netem_enqueue+0x29e6/0x3900 net/sched/sch_netem.c:516
Code: 45 8b 75 70 4c 89 6c 24 28 49 83 c5 74 4c 89 e9 48 c1 e9 03 8a 14 31 84 d2 48 8b 5c 24 10 0f 85 32 08 00 00 45 2b 75 00 31 d2 <41> f7 f6 49 01 d4 4c 89 e0 48 c1 e8 03 8a 04 30 84 c0 0f 85 45 08
RSP: 0018:ffffc90000bf74c0 EFLAGS: 00010246
RAX: 00000000e568b28f RBX: ffff888111316800 RCX: 1ffff1102371edc6
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff88811b8f6e30
RBP: ffffc90000bf75f0 R08: ffffffff8249afaa R09: 0000000000000003
R10: fffff5200017edfd R11: 1ffff9200017edfc R12: ffff88811118f480
R13: ffff88811b8f6e34 R14: 0000000000000000 R15: 0000000000000020
FS:  00007f0f55af5700(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000240 CR3: 000000014ce23000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	45 8b 75 70          	mov    0x70(%r13),%r14d
   4:	4c 89 6c 24 28       	mov    %r13,0x28(%rsp)
   9:	49 83 c5 74          	add    $0x74,%r13
   d:	4c 89 e9             	mov    %r13,%rcx
  10:	48 c1 e9 03          	shr    $0x3,%rcx
  14:	8a 14 31             	mov    (%rcx,%rsi,1),%dl
  17:	84 d2                	test   %dl,%dl
  19:	48 8b 5c 24 10       	mov    0x10(%rsp),%rbx
  1e:	0f 85 32 08 00 00    	jne    0x856
  24:	45 2b 75 00          	sub    0x0(%r13),%r14d
  28:	31 d2                	xor    %edx,%edx
* 2a:	41 f7 f6             	div    %r14d <-- trapping instruction
  2d:	49 01 d4             	add    %rdx,%r12
  30:	4c 89 e0             	mov    %r12,%rax
  33:	48 c1 e8 03          	shr    $0x3,%rax
  37:	8a 04 30             	mov    (%rax,%rsi,1),%al
  3a:	84 c0                	test   %al,%al
  3c:	0f                   	.byte 0xf
  3d:	85 45 08             	test   %eax,0x8(%rbp)

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-android-5-10 2022/05/30 08:43 android12-5.10-lts 0974b8411a58 a46af346 .config console log report info divide error in netem_enqueue
ci2-android-5-10 2022/05/19 12:08 android12-5.10-lts 0974b8411a58 cb1ac2e7 .config console log report info divide error in netem_enqueue
* Struck through repros no longer work on HEAD.