syzbot


WARNING: suspicious RCU usage in ovs_flow_tbl_masks_cache_resize

Status: fixed on 2020/11/16 12:12
Subsystems: openvswitch
[Documentation on labels]
Reported-by: syzbot+9a8f8bfcc56e8578016c@syzkaller.appspotmail.com
Fix commit: fea07a487c6d net: openvswitch: silence suspicious RCU usage warning
First crash: 1329d, last: 1329d
Cause bisection: failed (error log, bisect log)
  
Discussions (4)
Title Replies (including bot) Last reply
[PATCH 5.9 000/133] 5.9.7-rc1 review 139 (139) 2020/11/10 03:55
[PATCH net v2] net: openvswitch: silence suspicious RCU usage warning 2 (2) 2020/11/04 01:00
[PATCH net] net: openvswitch: silence suspicious RCU usage warning 5 (5) 2020/11/03 08:26
WARNING: suspicious RCU usage in ovs_flow_tbl_masks_cache_resize 1 (2) 2020/10/29 13:49
Last patch testing requests (2)
Created Duration User Patch Repo Result
2020/10/29 13:43 17m echaudro@redhat.com https://github.com/chaudron/kernel_net.git ovs_syzbot OK
2020/10/29 12:06 17m echaudro@redhat.com https://github.com/chaudron/kernel_net.git ovs_syzbot OK

Sample crash report:
netlink: 44 bytes leftover after parsing attributes in process `syz-executor522'.
=============================
WARNING: suspicious RCU usage
5.9.0-syzkaller #0 Not tainted
-----------------------------
net/openvswitch/flow_table.c:393 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-executor522/8493:
 #0: ffffffff8c9af210 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:810

stack backtrace:
CPU: 1 PID: 8493 Comm: syz-executor522 Not tainted 5.9.0-syzkaller #0
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+0x107/0x163 lib/dump_stack.c:118
 ovs_flow_tbl_masks_cache_resize+0x1bf/0x200 net/openvswitch/flow_table.c:393
 ovs_dp_change+0x231/0x2b0 net/openvswitch/datapath.c:1616
 ovs_dp_cmd_new+0x4c1/0xec0 net/openvswitch/datapath.c:1706
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739
 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440ad9
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 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffff6e416d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440ad9
RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000003
RBP: 00000000006cb018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004022e0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/28 04:34 net-old 6daa1da4e262 96e03c1c .config console log report syz C ci-upstream-net-this-kasan-gce
* Struck through repros no longer work on HEAD.