syzbot


general protection fault in em_cmp_match

Status: upstream: reported C repro on 2022/12/14 11:01
Reported-by: syzbot+0f85f339d85a5e331ec1@syzkaller.appspotmail.com
Fix commit: 134b529db48a net_sched: reject TCF_EM_SIMPLE case for complex ematch module
Patched on: [], missing on: [ci2-linux-4-19]
First crash: 527d, last: 527d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 general protection fault in em_cmp_match C error 1 530d 530d 2/2 fixed on 2023/05/04 14:51
linux-4.14 general protection fault in em_cmp_match C 1 522d 522d 1/1 fixed on 2023/01/18 11:20
android-5-15 general protection fault in em_cmp_match C error 1 530d 530d 2/2 fixed on 2023/02/02 00:40
upstream general protection fault in em_cmp_match net C 4 530d 526d 22/26 fixed on 2023/02/24 13:50

Sample crash report:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 19 Comm: kworker/1:0 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:em_cmp_match+0x51/0x590 net/sched/em_cmp.c:29
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f7 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 08 48 8d 7d 0a 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 93
RSP: 0018:ffff8880b5ad6bc0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880a712ac80 RCX: ffffffff869f8a05
RDX: 0000000000000001 RSI: ffffffff869fa079 RDI: 000000000000000a
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000004 R11: 0000000000000000 R12: ffff8880ab454e00
R13: ffff8880a712ac80 R14: ffffffff8ae79960 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08c504b3b0 CR3: 0000000009e6d000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tcf_em_match net/sched/ematch.c:496 [inline]
 __tcf_em_tree_match+0x14a/0x530 net/sched/ematch.c:522
 tcf_em_tree_match include/net/pkt_cls.h:531 [inline]
 basic_classify+0x1c0/0x2b0 net/sched/cls_basic.c:49
 tcf_classify+0x120/0x3c0 net/sched/cls_api.c:979
 prio_classify net/sched/sch_prio.c:46 [inline]
 prio_enqueue+0x3bb/0x7a0 net/sched/sch_prio.c:78
 __dev_xmit_skb net/core/dev.c:3494 [inline]
 __dev_queue_xmit+0x140a/0x2e00 net/core/dev.c:3807
 neigh_hh_output include/net/neighbour.h:491 [inline]
 neigh_output include/net/neighbour.h:499 [inline]
 ip_finish_output2+0xb6d/0x15a0 net/ipv4/ip_output.c:230
 ip_finish_output+0xae9/0x10b0 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_output+0x203/0x5f0 net/ipv4/ip_output.c:406
 dst_output include/net/dst.h:455 [inline]
 ip_local_out+0xaf/0x170 net/ipv4/ip_output.c:125
 iptunnel_xmit+0x63b/0x9d0 net/ipv4/ip_tunnel_core.c:91
 geneve_xmit_skb drivers/net/geneve.c:867 [inline]
 geneve_xmit+0x120d/0x2e60 drivers/net/geneve.c:943
 __netdev_start_xmit include/linux/netdevice.h:4349 [inline]
 netdev_start_xmit include/linux/netdevice.h:4363 [inline]
 xmit_one net/core/dev.c:3256 [inline]
 dev_hard_start_xmit+0x1a8/0x920 net/core/dev.c:3272
 __dev_queue_xmit+0x269d/0x2e00 net/core/dev.c:3838
 neigh_resolve_output+0x55a/0x910 net/core/neighbour.c:1374
 neigh_output include/net/neighbour.h:501 [inline]
 ip6_finish_output2+0x113d/0x2290 net/ipv6/ip6_output.c:120
 ip6_finish_output+0x89b/0x10f0 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip6_output+0x205/0x770 net/ipv6/ip6_output.c:209
 dst_output include/net/dst.h:455 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ndisc_send_skb+0xa24/0x1720 net/ipv6/ndisc.c:491
 ndisc_send_ns+0x51d/0x840 net/ipv6/ndisc.c:633
 addrconf_dad_work+0xb0e/0x10a0 net/ipv6/addrconf.c:4076
 process_one_work+0x864/0x1570 kernel/workqueue.c:2153
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Modules linked in:
---[ end trace 41d185f023e8efc0 ]---
RIP: 0010:em_cmp_match+0x51/0x590 net/sched/em_cmp.c:29
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 f7 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 08 48 8d 7d 0a 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 93
RSP: 0018:ffff8880b5ad6bc0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880a712ac80 RCX: ffffffff869f8a05
RDX: 0000000000000001 RSI: ffffffff869fa079 RDI: 000000000000000a
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000004 R11: 0000000000000000 R12: ffff8880ab454e00
R13: ffff8880a712ac80 R14: ffffffff8ae79960 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08c504b3b0 CR3: 0000000009e6d000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 89 fa             	mov    %rdi,%rdx
   3:	48 c1 ea 03          	shr    $0x3,%rdx
   7:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   b:	0f 85 f7 04 00 00    	jne    0x508
  11:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  18:	fc ff df
  1b:	48 8b 6b 08          	mov    0x8(%rbx),%rbp
  1f:	48 8d 7d 0a          	lea    0xa(%rbp),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx <-- trapping instruction
  2e:	48 89 f8             	mov    %rdi,%rax
  31:	83 e0 07             	and    $0x7,%eax
  34:	83 c0 01             	add    $0x1,%eax
  37:	38 d0                	cmp    %dl,%al
  39:	7c 08                	jl     0x43
  3b:	84 d2                	test   %dl,%dl
  3d:	0f                   	.byte 0xf
  3e:	85                   	.byte 0x85
  3f:	93                   	xchg   %eax,%ebx

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/12/14 11:01 linux-4.19.y 3f8a27f9e27b f6511626 .config console log report syz C [disk image] [vmlinux] ci2-linux-4-19 general protection fault in em_cmp_match
* Struck through repros no longer work on HEAD.