2019-03-19 16:03:16

by syzbot

[permalink] [raw]
Subject: WARNING: suspicious RCU usage in xfrm_alloc_userspi

Hello,

syzbot found the following crash on:

HEAD commit: b9998194 Add linux-next specific files for 20190318
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17a2e24d200000
kernel config: https://syzkaller.appspot.com/x/.config?x=59cd5d43b5df6955
dashboard link: https://syzkaller.appspot.com/bug?extid=59752237f7ab21c3f3c3
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14e70cb3200000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17292127200000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]

=============================
WARNING: suspicious RCU usage
5.1.0-rc1-next-20190318 #5 Not tainted
-----------------------------
net/xfrm/xfrm_user.c:1080 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor085/7946:
#0: 00000000a55031b5 (&net->xfrm.xfrm_cfg_mutex){+.+.}, at:
xfrm_netlink_rcv+0x61/0x90 net/xfrm/xfrm_user.c:2691

stack backtrace:
CPU: 0 PID: 7946 Comm: syz-executor085 Not tainted 5.1.0-rc1-next-20190318
#5
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5162
xfrm_nlmsg_unicast net/xfrm/xfrm_user.c:1080 [inline]
xfrm_alloc_userspi+0x7d5/0xa80 net/xfrm/xfrm_user.c:1356
xfrm_user_rcv_msg+0x458/0x770 net/xfrm/xfrm_user.c:2684
netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2485
xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2692
netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1336
netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1925
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xdd/0x130 net/socket.c:661
___sys_sendmsg+0x806/0x930 net/socket.c:2260
__sys_sendmsg+0x105/0x1d0 net/socket.c:2298
__do_sys_sendmsg net/socket.c:2307 [inline]
__se_sys_sendmsg net/socket.c:2305 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2305
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440499
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcf12caf08 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440499
RDX: 0000000000000000 RSI: 00000000200006c0 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000040


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches


2019-03-19 16:25:10

by Eric Dumazet

[permalink] [raw]
Subject: Re: WARNING: suspicious RCU usage in xfrm_alloc_userspi

CC Su Yanjun

On 03/19/2019 09:02 AM, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    b9998194 Add linux-next specific files for 20190318
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=17a2e24d200000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=59cd5d43b5df6955
> dashboard link: https://syzkaller.appspot.com/bug?extid=59752237f7ab21c3f3c3
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14e70cb3200000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17292127200000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: [email protected]
>
> =============================
> WARNING: suspicious RCU usage
> 5.1.0-rc1-next-20190318 #5 Not tainted
> -----------------------------
> net/xfrm/xfrm_user.c:1080 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 2, debug_locks = 1
> 1 lock held by syz-executor085/7946:
>  #0: 00000000a55031b5 (&net->xfrm.xfrm_cfg_mutex){+.+.}, at: xfrm_netlink_rcv+0x61/0x90 net/xfrm/xfrm_user.c:2691
>
> stack backtrace:
> CPU: 0 PID: 7946 Comm: syz-executor085 Not tainted 5.1.0-rc1-next-20190318 #5
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
>  lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5162
>  xfrm_nlmsg_unicast net/xfrm/xfrm_user.c:1080 [inline]
>  xfrm_alloc_userspi+0x7d5/0xa80 net/xfrm/xfrm_user.c:1356
>  xfrm_user_rcv_msg+0x458/0x770 net/xfrm/xfrm_user.c:2684
>  netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2485
>  xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2692
>  netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
>  netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1336
>  netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1925
>  sock_sendmsg_nosec net/socket.c:651 [inline]
>  sock_sendmsg+0xdd/0x130 net/socket.c:661
>  ___sys_sendmsg+0x806/0x930 net/socket.c:2260
>  __sys_sendmsg+0x105/0x1d0 net/socket.c:2298
>  __do_sys_sendmsg net/socket.c:2307 [inline]
>  __se_sys_sendmsg net/socket.c:2305 [inline]
>  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2305
>  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x440499
> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007ffcf12caf08 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440499
> RDX: 0000000000000000 RSI: 00000000200006c0 RDI: 0000000000000003
> RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000040
>
>
> ---
> This bug is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at [email protected].
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.
> syzbot can test patches for this bug, for details see:
> https://goo.gl/tpsmEJ#testing-patches

2019-03-19 21:00:34

by syzbot

[permalink] [raw]
Subject: Re: WARNING: suspicious RCU usage in xfrm_alloc_userspi

syzbot has bisected this bug to:

commit f10e0010fae8174dc20bdc872bcaa85baa925cb7
Author: Su Yanjun <[email protected]>
Date: Thu Mar 7 01:54:08 2019 +0000

net: xfrm: Add '_rcu' tag for rcu protected pointer in netns_xfrm

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1644ec8b200000
start commit: f10e0010 net: xfrm: Add '_rcu' tag for rcu protected point..
git tree: linux-next
final crash: https://syzkaller.appspot.com/x/report.txt?x=1544ec8b200000
console output: https://syzkaller.appspot.com/x/log.txt?x=1144ec8b200000
kernel config: https://syzkaller.appspot.com/x/.config?x=59cd5d43b5df6955
dashboard link: https://syzkaller.appspot.com/bug?extid=59752237f7ab21c3f3c3
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14e70cb3200000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17292127200000

Reported-by: [email protected]
Fixes: f10e0010 ("net: xfrm: Add '_rcu' tag for rcu protected pointer in
netns_xfrm")

2019-03-20 00:57:01

by Su, Yanjun

[permalink] [raw]
Subject: Re: WARNING: suspicious RCU usage in xfrm_alloc_userspi


On 2019/3/20 0:23, Eric Dumazet wrote:
> CC Su Yanjun
>
> On 03/19/2019 09:02 AM, syzbot wrote:
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit:    b9998194 Add linux-next specific files for 20190318
>> git tree:       linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=17a2e24d200000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=59cd5d43b5df6955
>> dashboard link: https://syzkaller.appspot.com/bug?extid=59752237f7ab21c3f3c3
>> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14e70cb3200000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17292127200000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: [email protected]
>>
>> =============================
>> WARNING: suspicious RCU usage
>> 5.1.0-rc1-next-20190318 #5 Not tainted
>> -----------------------------
>> net/xfrm/xfrm_user.c:1080 suspicious rcu_dereference_check() usage!
>>
>> other info that might help us debug this:
>>
>>
>> rcu_scheduler_active = 2, debug_locks = 1
>> 1 lock held by syz-executor085/7946:
>>  #0: 00000000a55031b5 (&net->xfrm.xfrm_cfg_mutex){+.+.}, at: xfrm_netlink_rcv+0x61/0x90 net/xfrm/xfrm_user.c:2691
>>
>> stack backtrace:
>> CPU: 0 PID: 7946 Comm: syz-executor085 Not tainted 5.1.0-rc1-next-20190318 #5
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>> Call Trace:
>>  __dump_stack lib/dump_stack.c:77 [inline]
>>  dump_stack+0x172/0x1f0 lib/dump_stack.c:113
>>  lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5162
>>  xfrm_nlmsg_unicast net/xfrm/xfrm_user.c:1080 [inline]
>>  xfrm_alloc_userspi+0x7d5/0xa80 net/xfrm/xfrm_user.c:1356
>>  xfrm_user_rcv_msg+0x458/0x770 net/xfrm/xfrm_user.c:2684
>>  netlink_rcv_skb+0x17a/0x460 net/netlink/af_netlink.c:2485
>>  xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2692
>>  netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
>>  netlink_unicast+0x536/0x720 net/netlink/af_netlink.c:1336
>>  netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1925
>>  sock_sendmsg_nosec net/socket.c:651 [inline]
>>  sock_sendmsg+0xdd/0x130 net/socket.c:661
>>  ___sys_sendmsg+0x806/0x930 net/socket.c:2260
>>  __sys_sendmsg+0x105/0x1d0 net/socket.c:2298
>>  __do_sys_sendmsg net/socket.c:2307 [inline]
>>  __se_sys_sendmsg net/socket.c:2305 [inline]
>>  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2305
>>  do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
>>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x440499
>> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
>> RSP: 002b:00007ffcf12caf08 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
>> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440499
>> RDX: 0000000000000000 RSI: 00000000200006c0 RDI: 0000000000000003
>> RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
>> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000040
>>
>>
>> ---
>> This bug is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at [email protected].
>>
>> syzbot will keep track of this bug report. See:
>> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.
>> syzbot can test patches for this bug, for details see:
>> https://goo.gl/tpsmEJ#testing-patches

I  got it.

Thanks