suspicious RCU usage in net/wireless/util.c:778
Dear all,
once the (wifi) link becomes ready, the following warning is emitted on
mainline (v4.15-rc4-202-gead68f216110) on my notebook:
[ 22.770422] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 22.772364] =
[ 22.772369] WARNING: suspicious RCU usage
[ 22.772375] 4.15.0-rc4+ #5 Not tainted
[ 22.772380] -
[ 22.772386] /home/brodo/local/kernel/git/linux/net/wireless/util.c:778
suspicious rcu_dereference_check() usage!
[ 22.772391]
[ 22.772397]
[ 22.772402] 4 locks held by wpa_supplicant/774:
[ 22.772407] #0: (cb_lock){}, at: [<276dc3a0>]
genl_rcv+0x15/0x40
[ 22.772437] #1: (genl_mutex){+.+.}, at: [<24d83eb3>]
genl_rcv_msg+0x7a/0x90
[ 22.772463] #2: (rtnl_mutex){+.+.}, at: [<9de25a59>]
nl80211_pre_doit+0xe9/0x190
[ 22.772489] #3: (&wdev->mtx){+.+.}, at: [<89bf2cfd>]
nl80211_send_iface+0x317/0x8d0
[ 22.772516]
[ 22.772522] CPU: 3 PID: 774 Comm: wpa_supplicant Not tainted 4.15.0-rc4+ #5
[ 22.772528] Hardware name: Dell Inc. XPS 13 9343/0TM99H, BIOS A11 12/08/2016
[ 22.772532] Call Trace:
[ 22.772544] dump_stack+0x67/0x95
[ 22.772553] ieee80211_bss_get_ie+0x66/0x70
[ 22.772562] nl80211_send_iface+0x344/0x8d0
[ 22.772585] nl80211_get_interface+0x4b/0xa0
[ 22.772598] genl_family_rcv_msg+0x32e/0x3f0
[ 22.772607] ? preempt_count_sub+0x92/0xd0
[ 22.772645] genl_rcv_msg+0x47/0x90
[ 22.772652] ? genl_family_rcv_msg+0x3f0/0x3f0
[ 22.772661] netlink_rcv_skb+0x8a/0x120
[ 22.772677] genl_rcv+0x24/0x40
[ 22.772684] netlink_unicast+0x174/0x1f0
[ 22.772698] netlink_sendmsg+0x386/0x3d0
[ 22.772719] sock_sendmsg+0x2d/0x40
[ 22.772728] ___sys_sendmsg+0x2a7/0x300
[ 22.772748] ? netlink_sendmsg+0x13d/0x3d0
[ 22.772791] ? __sys_sendmsg+0x67/0xb0
[ 22.772797] __sys_sendmsg+0x67/0xb0
[ 22.772822] entry_SYSCALL_64_fastpath+0x18/0x85
This warning wasn't present in 4.15. Despite of it, networking seems to
work fine. Nonetheless, the code seems to need a bugfix.
Thanks,
Dominik
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v4.15-rc5 warning: suspicious RCU usage in net/wireless/util.c:778
On Fri, Dec 22, 2017 at 08:20:12AM +0100, Dominik Brodowski wrote:
> Dear all,
>
> once the (wifi) link becomes ready, the following warning is emitted on
> mainline (v4.15-rc4-202-gead68f216110) on my notebook:
... and it is still present as of v4.15-rc5-149-g5aa90a845892
> [ 22.770422] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
>
> [ 22.772364] =
> [ 22.772369] WARNING: suspicious RCU usage
> [ 22.772375] 4.15.0-rc4+ #5 Not tainted
> [ 22.772380] -
> [ 22.772386] /home/brodo/local/kernel/git/linux/net/wireless/util.c:778
> suspicious rcu_dereference_check() usage!
> [ 22.772391]
> [ 22.772397]
> [ 22.772402] 4 locks held by wpa_supplicant/774:
> [ 22.772407] #0: (cb_lock){}, at: [<276dc3a0>]
> genl_rcv+0x15/0x40
> [ 22.772437] #1: (genl_mutex){+.+.}, at: [<24d83eb3>]
> genl_rcv_msg+0x7a/0x90
> [ 22.772463] #2: (rtnl_mutex){+.+.}, at: [<9de25a59>]
> nl80211_pre_doit+0xe9/0x190
> [ 22.772489] #3: (&wdev->mtx){+.+.}, at: [<89bf2cfd>]
> nl80211_send_iface+0x317/0x8d0
> [ 22.772516]
> [ 22.772522] CPU: 3 PID: 774 Comm: wpa_supplicant Not tainted 4.15.0-rc4+ #5
> [ 22.772528] Hardware name: Dell Inc. XPS 13 9343/0TM99H, BIOS A11
> 12/08/2016
> [ 22.772532] Call Trace:
> [ 22.772544] dump_stack+0x67/0x95
> [ 22.772553] ieee80211_bss_get_ie+0x66/0x70
> [ 22.772562] nl80211_send_iface+0x344/0x8d0
> [ 22.772585] nl80211_get_interface+0x4b/0xa0
> [ 22.772598] genl_family_rcv_msg+0x32e/0x3f0
> [ 22.772607] ? preempt_count_sub+0x92/0xd0
> [ 22.772645] genl_rcv_msg+0x47/0x90
> [ 22.772652] ? genl_family_rcv_msg+0x3f0/0x3f0
> [ 22.772661] netlink_rcv_skb+0x8a/0x120
> [ 22.772677] genl_rcv+0x24/0x40
> [ 22.772684] netlink_unicast+0x174/0x1f0
> [ 22.772698] netlink_sendmsg+0x386/0x3d0
> [ 22.772719] sock_sendmsg+0x2d/0x40
> [ 22.772728] ___sys_sendmsg+0x2a7/0x300
> [ 22.772748] ? netlink_sendmsg+0x13d/0x3d0
> [ 22.772791] ? __sys_sendmsg+0x67/0xb0
> [ 22.772797] __sys_sendmsg+0x67/0xb0
> [ 22.772822] entry_SYSCALL_64_fastpath+0x18/0x85
>
> This warning wasn't present in 4.15. Despite of it, networking seems to
> work fine. Nonetheless, the code seems to need a bugfix.
Thanks,
Dominik
v4.15-rc7 regression/warning: suspicious RCU usage in net/wireless/util.c:778
On Sat, Dec 30, 2017 at 02:11:33PM +0100, Dominik Brodowski wrote:
> On Fri, Dec 22, 2017 at 08:20:12AM +0100, Dominik Brodowski wrote:
> > Dear all,
> >
> > once the (wifi) link becomes ready, the following warning is emitted on
> > mainline (v4.15-rc4-202-gead68f216110) on my notebook:
>
> ... and it is still present as of v4.15-rc5-149-g5aa90a845892
... and still present in v4.15-rc7:
[0.00] Linux version 4.15.0-rc7+ (brodo@light) (gcc version 7.2.1
20171224 (GCC)) #2 SMP PREEMPT Mon Jan 8 08:58:57 CET 2018
...
[ 19.182497] wlan0: associated
[ 19.323473] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 19.324512] =
[ 19.324525] WARNING: suspicious RCU usage
[ 19.324531] 4.15.0-rc7+ #2 Not tainted
[ 19.324535] -
[ 19.324541] /home/brodo/local/kernel/git/linux/net/wireless/util.c:778
suspicious rcu_dereference_check() usage!
[ 19.324545]
other info that might help us debug this:
[ 19.324551]
rcu_scheduler_active = 2, debug_locks = 1
[ 19.324556] 4 locks held by wpa_supplicant/777:
[ 19.324561] #0: (cb_lock){}, at: []
genl_rcv+0x15/0x40
[ 19.324590] #1: (genl_mutex){+.+.}, at: [<88de9868>]
genl_rcv_msg+0x7a/0x90
[ 19.324614] #2: (rtnl_mutex){+.+.}, at: []
nl80211_pre_doit+0xe9/0x190
[ 19.324639] #3: (&wdev->mtx){+.+.}, at: [<15e6766b>]
nl80211_send_iface+0x319/0x8d0
[ 19.324663]
stack backtrace:
[ 19.324670] CPU: 3 PID: 777 Comm: wpa_supplicant Not tainted 4.15.0-rc7+ #2
[ 19.324674] Hardware name: Dell Inc. XPS 13 9343/0TM99H, BIOS A11 12/08/2016
[ 19.324679] Call Trace:
[ 19.324690] dump_stack+0x67/0x95
[ 19.324698] ieee80211_bss_get_ie+0x66/0x70
[ 19.324707] nl80211_send_iface+0x346/0x8d0
[ 19.324726] nl80211_get_interface+0x4b/0xa0
[ 19.324738] genl_family_rcv_msg+0x32e/0x3f0
[ 19.324747] ? preempt_count_sub+0x92/0xd0
[ 19.324780] genl_rcv_msg+0x47/0x90
[ 19.324787] ? genl_family_rcv_msg+0x3f0/0x3f0
[ 19.324796] netlink_rcv_skb+0x8a/0x120
[ 19.324811] genl_rcv+0x24/0x40
[ 19.324818] netlink_unicast+0x174/0x1f0
[ 19.324831] netlink_sendmsg+0x383/0x3d0
[ 19.324851] sock_sendmsg+0x2d/0x40
[ 19.324859] ___sys_sendmsg+0x2a8/0x300
[ 19.324877] ? netlink_sendmsg+0x13a/0x3d0
[ 19.324919] ? __sys_sendmsg+0x67/0xb0
[ 19.324925] __sys_sendmsg+0x67/0xb0
[ 19.324949] entry_SYSCALL_64_fastpath+0x18/0x85
[ 19.324955] RIP: 0033:0x779ea30ac037
[ 19.324960] RSP: 002b:7ffd9ea8aa28 EFLAGS: 0246
Anyone?
Thanks,
Dominik
