Subject: [syzbot] WARNING: suspicious RCU usage in bond_ethtool_get_ts_info

From: syzbot <[email-masked]>
Date: Thu, 12 May 2022 12:35:28 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    01f4685797a5 eth: amd: remove NI6510 support (ni65)
git tree:       net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16391d99f00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c04cc4641789ea51
dashboard link: https://syzkaller.appspot.com/bug?extid=92beb3d46aab498710fa
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17df03e1f00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12159cbef00000

The issue was bisected to:

commit aa6034678e873db8bd5c5a4b73f8b88c469374d6
Author: Hangbin Liu <[email-masked]>
Date:   Fri Jan 21 08:25:18 2022 +0000

    bonding: use rcu_dereference_rtnl when get bonding active slave

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16fce349f00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=15fce349f00000
console output: https://syzkaller.appspot.com/x/log.txt?x=11fce349f00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: aa6034678e87 ("bonding: use rcu_dereference_rtnl when get bonding active slave")

=============================
WARNING: suspicious RCU usage
5.18.0-rc5-syzkaller-01392-g01f4685797a5 #0 Not tainted
-----------------------------
include/net/bonding.h:353 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-executor317/3599:
 #0: ffff88801de78130 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1680 [inline]
 #0: ffff88801de78130 (sk_lock-AF_INET){+.+.}-{0:0}, at: sock_setsockopt+0x1e3/0x2ec0 net/core/sock.c:1066

stack backtrace:
CPU: 0 PID: 3599 Comm: syz-executor317 Not tainted 5.18.0-rc5-syzkaller-01392-g01f4685797a5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 bond_option_active_slave_get_rcu include/net/bonding.h:353 [inline]
 bond_ethtool_get_ts_info+0x32c/0x3a0 drivers/net/bonding/bond_main.c:5595
 __ethtool_get_ts_info+0x173/0x240 net/ethtool/common.c:554
 ethtool_get_phc_vclocks+0x99/0x110 net/ethtool/common.c:568
 sock_timestamping_bind_phc net/core/sock.c:869 [inline]
 sock_set_timestamping+0x3a3/0x7e0 net/core/sock.c:916
 sock_setsockopt+0x543/0x2ec0 net/core/sock.c:1221
 __sys_setsockopt+0x55e/0x6a0 net/socket.c:2223
 __do_sys_setsockopt net/socket.c:2238 [inline]
 __se_sys_setsockopt net/socket.c:2235 [inline]
 __x64_sys_setsockopt+0xba/0x150 net/socket.c:2235
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f8902c8eb39
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48

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