Hi,
I found a warning while fuzzing with Syzkaller on linux 4.13-rc6 on
x86_64. The full stack trace is below:
------------[ cut here ]------------
WARNING: CPU: 3 PID: 32413 at net/core/dev.c:2592
skb_warn_bad_offload+0x2a9/0x380 net/core/dev.c:2587
Kernel panic - not syncing: panic_on_warn set ...
CPU: 3 PID: 32413 Comm: syz-executor3 Not tainted 4.13.0-rc6+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:16 [inline]
dump_stack+0x95/0xeb lib/dump_stack.c:52
panic+0x1ae/0x387 kernel/panic.c:180
__warn+0x1c4/0x1d9 kernel/panic.c:541
report_bug+0x213/0x2d0 lib/bug.c:183
fixup_bug+0x3f/0x90 arch/x86/kernel/traps.c:190
do_trap_no_signal arch/x86/kernel/traps.c:224 [inline]
do_trap+0x13a/0x3e0 arch/x86/kernel/traps.c:273
do_error_trap+0x11e/0x1f0 arch/x86/kernel/traps.c:310
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323
invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:846
RIP: 0010:skb_warn_bad_offload+0x2a9/0x380 net/core/dev.c:2587
RSP: 0018:ffff88006996f460 EFLAGS: 00010286
RAX: 000000000000006d RBX: ffff88006b1813e8 RCX: 0000000000000000
RDX: 000000000000006d RSI: ffffffff8122d81e RDI: ffffed000d32de80
RBP: ffff88006996f4b8 R08: ffffffff83ad0fd8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88003d5bc5a0
R13: 0000000000000000 R14: ffff88003d5bc5a0 R15: 0000000000000bd0
SELinux: unrecognized netlink message: protocol=9 nlmsg_type=5
sclass=netlink_audit_socket pig=32438 comm=syz-executor0
__skb_gso_segment+0x5a3/0x6d0 net/core/dev.c:2799
skb_gso_segment include/linux/netdevice.h:3957 [inline]
validate_xmit_skb+0x42d/0xa20 net/core/dev.c:3049
SELinux: unrecognized netlink message: protocol=9 nlmsg_type=5
sclass=netlink_audit_socket pig=32441 comm=syz-executor0
__dev_queue_xmit+0xc9f/0x18b0 net/core/dev.c:3472
dev_queue_xmit+0x17/0x20 net/core/dev.c:3513
neigh_hh_output include/net/neighbour.h:471 [inline]
neigh_output include/net/neighbour.h:479 [inline]
ip6_finish_output2+0x119b/0x1dd0 net/ipv6/ip6_output.c:120
ip6_finish_output+0x3a0/0x770 net/ipv6/ip6_output.c:146
NF_HOOK_COND include/linux/netfilter.h:237 [inline]
ip6_output+0x211/0x6e0 net/ipv6/ip6_output.c:163
dst_output include/net/dst.h:471 [inline]
ip6_local_out+0x95/0x160 net/ipv6/output_core.c:178
ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1735
udp_v6_send_skb+0x30a/0xe90 net/ipv6/udp.c:1059
udpv6_sendmsg+0x1b4f/0x2540 net/ipv6/udp.c:1331
inet_sendmsg+0x123/0x500 net/ipv4/af_inet.c:762
sock_sendmsg_nosec net/socket.c:633 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:643
SYSC_sendto+0x20d/0x340 net/socket.c:1736
SyS_sendto+0x40/0x50 net/socket.c:1704
entry_SYSCALL_64_fastpath+0x18/0xad
RIP: 0033:0x452309
RSP: 002b:00007fe2d89a0c08 EFLAGS: 00000216 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000718150 RCX: 0000000000452309
RDX: 0000000000000bd7 RSI: 00000000205d2000 RDI: 0000000000000015
RBP: 0000000000000046 R08: 0000000020226fe4 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004bf2e0
R13: 00000000ffffffff R14: ffffffffffffffff R15: 00000000c08c5335
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..
On Mon, Sep 11, 2017 at 12:20:32PM +0800, Dison River wrote:
> I found a warning while fuzzing with Syzkaller on linux 4.13-rc6 on
> x86_64. The full stack trace is below:
>
> ------------[ cut here ]------------
> WARNING: CPU: 3 PID: 32413 at net/core/dev.c:2592
> skb_warn_bad_offload+0x2a9/0x380 net/core/dev.c:2587
> Kernel panic - not syncing: panic_on_warn set ...
>
> CPU: 3 PID: 32413 Comm: syz-executor3 Not tainted 4.13.0-rc6+ #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
Are you sure you didn't omit something? This WARN() check should write
some useful information but I can't see it in your mail:
WARN(1, "%s: caps=(%pNF, %pNF) len=%d data_len=%d gso_size=%d "
"gso_type=%d ip_summed=%d\n",
name, dev ? &dev->features : &null_features,
skb->sk ? &skb->sk->sk_route_caps : &null_features,
skb->len, skb->data_len, skb_shinfo(skb)->gso_size,
skb_shinfo(skb)->gso_type, skb->ip_summed);
Michal Kubecek
On Wed, Nov 01, 2017 at 09:50:18PM +0300, 'Dmitry Vyukov' via syzkaller-bugs wrote:
> On Wed, Nov 1, 2017 at 9:48 PM, syzbot
> <bot+abb66e15eb1b298dfe4a13375f18a278d5940e6f@syzkaller.appspotmail.com>
> wrote:
> > Hello,
> >
> > syzkaller hit the following crash on
> > 720bbe532b7c8f5613b48dea627fc58ed9ace707
> > git://git.cmpxchg.org/linux-mmots.git/master
> > compiler: gcc (GCC) 7.1.1 20170620
> > .config is attached
> > Raw console output is attached.
> > C reproducer is attached
> > syzkaller reproducer is attached. See https://goo.gl/kgGztJ
> > for information about syzkaller reproducers
>
>
> This also happens on more recent commits, including linux-next
> 36ef71cae353f88fd6e095e2aaa3e5953af1685d (Oct 20):
>
> syz0: caps=(0x00000400000058c1, 0x0000000000000000) len=4203
> data_len=2810 gso_size=8465 gso_type=3 ip_summed=0
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 3473 at net/core/dev.c:2618
> skb_warn_bad_offload.cold.139+0x224/0x261 net/core/dev.c:2613
> Kernel panic - not syncing: panic_on_warn set ...
>
> CPU: 0 PID: 3473 Comm: a.out Not tainted 4.14.0-rc5-next-20171018 #15
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:16 [inline]
> dump_stack+0x1a8/0x272 lib/dump_stack.c:52
> panic+0x21e/0x4b7 kernel/panic.c:183
> __warn.cold.6+0x182/0x187 kernel/panic.c:546
> report_bug+0x232/0x330 lib/bug.c:183
> fixup_bug+0x3f/0x90 arch/x86/kernel/traps.c:177
> do_trap_no_signal arch/x86/kernel/traps.c:211 [inline]
> do_trap+0x132/0x280 arch/x86/kernel/traps.c:260
> do_error_trap+0x11f/0x390 arch/x86/kernel/traps.c:297
> do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:310
> invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
> RIP: 0010:skb_warn_bad_offload.cold.139+0x224/0x261 net/core/dev.c:2613
> RSP: 0018:ffff880064797038 EFLAGS: 00010286
> RAX: 000000000000006f RBX: ffff88006365efe8 RCX: 0000000000000000
> RDX: 000000000000006f RSI: ffffffff815c88c1 RDI: ffffed000c8f2dfd
> RBP: ffff880064797090 R08: ffff8800686f86c0 R09: 0000000000000002
> R10: ffff8800686f86c0 R11: 0000000000000000 R12: ffff8800538b1680
> R13: 0000000000000000 R14: ffff8800538b1680 R15: 0000000000002111
> __skb_gso_segment+0x69e/0x860 net/core/dev.c:2824
> skb_gso_segment include/linux/netdevice.h:3971 [inline]
> validate_xmit_skb+0x29f/0xca0 net/core/dev.c:3074
> validate_xmit_skb_list+0xb7/0x120 net/core/dev.c:3125
> sch_direct_xmit+0x5b5/0x710 net/sched/sch_generic.c:181
> __dev_xmit_skb net/core/dev.c:3206 [inline]
> __dev_queue_xmit+0x1e41/0x2350 net/core/dev.c:3473
> dev_queue_xmit+0x17/0x20 net/core/dev.c:3538
> packet_snd net/packet/af_packet.c:2956 [inline]
> packet_sendmsg+0x487a/0x64b0 net/packet/af_packet.c:2981
> sock_sendmsg_nosec net/socket.c:632 [inline]
> sock_sendmsg+0xd2/0x120 net/socket.c:642
> ___sys_sendmsg+0x7cc/0x900 net/socket.c:2048
> __sys_sendmsg+0xe6/0x220 net/socket.c:2082
> SYSC_sendmsg net/socket.c:2093 [inline]
> SyS_sendmsg+0x36/0x60 net/socket.c:2089
> entry_SYSCALL_64_fastpath+0x1f/0xbe
> RIP: 0033:0x44bab9
> RSP: 002b:00000000007eff18 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000020001046 RCX: 000000000044bab9
> RDX: 0000000000004010 RSI: 00000000207fcfc8 RDI: 0000000000000004
> RBP: 0000000000000086 R08: 850b2da14d2a3706 R09: 0000000000000000
> R10: 1b91126b7f398aaa R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000407950 R14: 00000000004079e0 R15: 0000000000000000
>
>
>
>
>
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 2986 at net/core/dev.c:2585
> > skb_warn_bad_offload+0x2a9/0x380 net/core/dev.c:2580
> > Kernel panic - not syncing: panic_on_warn set ...
> >
> > CPU: 0 PID: 2986 Comm: syzkaller546001 Not tainted 4.13.0-mm1+ #7
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 01/01/2011
> > Call Trace:
> > __dump_stack lib/dump_stack.c:16 [inline]
> > dump_stack+0x194/0x257 lib/dump_stack.c:52
> > panic+0x1e4/0x417 kernel/panic.c:181
> > __warn+0x1c4/0x1d9 kernel/panic.c:542
> > report_bug+0x211/0x2d0 lib/bug.c:183
> > fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
> > do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
> > do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
> > do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
> > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
> > invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
> > RIP: 0010:skb_warn_bad_offload+0x2a9/0x380 net/core/dev.c:2580
> > RSP: 0018:ffff8801ce73f0a0 EFLAGS: 00010282
> > RAX: 000000000000006f RBX: ffff8801cd84cde0 RCX: 0000000000000000
> > RDX: 000000000000006f RSI: 1ffff10039ce7dd4 RDI: ffffed0039ce7e08
> > RBP: ffff8801ce73f0f8 R08: ffff8801ce73e790 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801ce7802c0
> > R13: 0000000000000000 R14: ffff8801ce7802c0 R15: 0000000000002111
> > __skb_gso_segment+0x607/0x7f0 net/core/dev.c:2791
> > skb_gso_segment include/linux/netdevice.h:3951 [inline]
> > validate_xmit_skb+0x4ba/0xb20 net/core/dev.c:3041
> > validate_xmit_skb_list+0xb7/0x120 net/core/dev.c:3092
> > sch_direct_xmit+0x3b6/0x6d0 net/sched/sch_generic.c:181
> > __dev_xmit_skb net/core/dev.c:3173 [inline]
> > __dev_queue_xmit+0x15fe/0x1e40 net/core/dev.c:3440
> > dev_queue_xmit+0x17/0x20 net/core/dev.c:3505
> > packet_snd net/packet/af_packet.c:2950 [inline]
> > packet_sendmsg+0x3bbf/0x6030 net/packet/af_packet.c:2975
> > sock_sendmsg_nosec net/socket.c:633 [inline]
> > sock_sendmsg+0xca/0x110 net/socket.c:643
> > ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2049
> > __sys_sendmsg+0xe5/0x210 net/socket.c:2083
> > SYSC_sendmsg net/socket.c:2094 [inline]
> > SyS_sendmsg+0x2d/0x50 net/socket.c:2090
> > entry_SYSCALL_64_fastpath+0x1f/0xbe
> > RIP: 0033:0x445489
> > RSP: 002b:00000000007efe68 EFLAGS: 00000217 ORIG_RAX: 000000000000002e
> > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445489
> > RDX: 0000000000004010 RSI: 00000000207fcfc8 RDI: 0000000000000004
> > RBP: 0000000000000082 R08: 000000000000cdf3 R09: 000000000000cdf3
> > R10: 0000000000000004 R11: 0000000000000217 R12: 0000000000402ae0
> > R13: 0000000000402b70 R14: 0000000000000000 R15: 0000000000000000
> > Dumping ftrace buffer:
> > (ftrace buffer empty)
> > Kernel Offset: disabled
> > Rebooting in 86400 seconds..
> >
> >
> > ---
> > This bug is generated by a dumb bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for details.
> > Direct all questions to [email protected].
> > Please credit me with: Reported-by: syzbot <[email protected]>
> >
> > syzbot will keep track of this bug report.
> > Once a fix for this bug is committed, please reply to this email with:
> > #syz fix: exact-commit-title
Apparently fixed by commit 8d74e9f88d65a, so telling syzbot:
#syz fix: net: avoid skb_warn_bad_offload on IS_ERR
- Eric