syzbot


BUG: unable to handle kernel NULL pointer dereference in ip6_rcv_finish

Status: fixed on 2019/06/18 17:49
Subsystems: net
[Documentation on labels]
Fix commit: 61fb0d016807 ipv6: prevent possible fib6 leaks
First crash: 1857d, last: 1828d

Sample crash report:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 86246067 P4D 86246067 PUD 86247067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.2.0-rc2+ #36
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events rt6_probe_deferred
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8880ae809bc8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888098208838 RCX: ffffffff861b59cb
RDX: 1ffff1101304110c RSI: ffffffff861b59d5 RDI: ffff8880a0b00780
RBP: ffff8880ae809bf8 R08: ffff8880a987c140 R09: 0000000000000005
R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: ffff8880a0b00780
R13: 0000000000000000 R14: ffff8880a0b007d8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000086245000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 dst_input include/net/dst.h:439 [inline]
 ip6_rcv_finish+0x1de/0x310 net/ipv6/ip6_input.c:80
 NF_HOOK include/linux/netfilter.h:305 [inline]
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0x10e/0x420 net/ipv6/ip6_input.c:276
 __netif_receive_skb_one_core+0x113/0x1a0 net/core/dev.c:4985
 __netif_receive_skb+0x2c/0x1d0 net/core/dev.c:5099
 process_backlog+0x206/0x750 net/core/dev.c:5910
 napi_poll net/core/dev.c:6333 [inline]
 net_rx_action+0x4f5/0x1070 net/core/dev.c:6399
 __do_softirq+0x25c/0x94c kernel/softirq.c:293
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
 </IRQ>
 do_softirq.part.0+0x11a/0x170 kernel/softirq.c:338
 do_softirq kernel/softirq.c:330 [inline]
 __local_bh_enable_ip+0x211/0x270 kernel/softirq.c:190
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:684 [inline]
 ip6_finish_output2+0x10a0/0x2550 net/ipv6/ip6_output.c:121
 ip6_finish_output+0x56d/0xc20 net/ipv6/ip6_output.c:154
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0x235/0x7f0 net/ipv6/ip6_output.c:171
 dst_output include/net/dst.h:433 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ndisc_send_skb+0xf29/0x14a0 net/ipv6/ndisc.c:508
 ndisc_send_ns+0x3a9/0x850 net/ipv6/ndisc.c:650
 rt6_probe_deferred+0xe3/0x1a0 net/ipv6/route.c:543
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Modules linked in:
CR2: 0000000000000000
---[ end trace 2f6d2a9471ac9e82 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8880ae809bc8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff888098208838 RCX: ffffffff861b59cb
RDX: 1ffff1101304110c RSI: ffffffff861b59d5 RDI: ffff8880a0b00780
RBP: ffff8880ae809bf8 R08: ffff8880a987c140 R09: 0000000000000005
R10: ffffed1015d06bdf R11: ffff8880ae835efb R12: ffff8880a0b00780
R13: 0000000000000000 R14: ffff8880a0b007d8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000086245000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/06/02 00:52 net-old e8d67fa5696e 53c81ea5 .config console log report ci-upstream-net-this-kasan-gce
2019/05/14 17:51 net-old 63863ee8e2f6 ada3c44c .config console log report ci-upstream-net-this-kasan-gce
2019/06/11 23:03 net-next-old 758a0a4d60ab ea2f4006 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.