From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominik Brodowski Subject: suspicious RCU usage in net/wireless/util.c:778 Date: Fri, 22 Dec 2017 08:20:12 +0100 Message-ID: <20171222072012.GA3110@light.dominikbrodowski.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="BXVAT5kNtrzKuDFl" To: netdev@vger.kernel.org Return-path: Received: from isilmar-4.linta.de ([136.243.71.142]:60108 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786AbdLVH2z (ORCPT ); Fri, 22 Dec 2017 02:28:55 -0500 Received: from light.dominikbrodowski.net (isilmar.linta [10.0.0.1]) by isilmar-4.linta.de (Postfix) with ESMTPS id E7F432008DB for ; Fri, 22 Dec 2017 07:20:57 +0000 (UTC) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: --BXVAT5kNtrzKuDFl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D [ 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 s= uspicious rcu_dereference_check() usage! [ 22.772391]=20 [ 22.772397]=20 [ 22.772402] 4 locks held by wpa_supplicant/774: [ 22.772407] #0: (cb_lock){++++}, at: [<00000000276dc3a0>] genl_rcv+0x1= 5/0x40 [ 22.772437] #1: (genl_mutex){+.+.}, at: [<0000000024d83eb3>] genl_rcv_= msg+0x7a/0x90 [ 22.772463] #2: (rtnl_mutex){+.+.}, at: [<000000009de25a59>] nl80211_p= re_doit+0xe9/0x190 [ 22.772489] #3: (&wdev->mtx){+.+.}, at: [<0000000089bf2cfd>] nl80211_s= end_iface+0x317/0x8d0 [ 22.772516]=20 [ 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 --BXVAT5kNtrzKuDFl Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEmgXaWKgmjrvkPhLCmpdgiUyNow0FAlo8sikACgkQmpdgiUyN ow3psQ//TuCU6tgFEn6ceSBjdCIIBkX9izr9voSLx+DXrDW6Qe7Op3ZRk3jHgTDd LNT2qhOHTtWAq+zSlCH8npG4egLeQ4h2dcdiLdLXcFyefppK/GJry+jTFyJBsw4u uRxrCqgxtE4qGlEXdHpoB9qCs/QxoGQZ70Eb4T4LQRi/YcaAXWe3QjrQelITy+P0 Z2dMKZ1YGD18KKffBfoEEhpfFYg9bpK17keZUrNqgdk2FoZwdwjAKEk6DUTwF1ri UizNHREDPM9IYU63uqfMsrzlijCBE07g0/kpniNT/RSr8z7yGyG2YylJVgFHvrPd IiRHCqg1LK4HVHvyPIoriLMFPbeHs7+qKH98mme3JwckGV1oXVN2wKAb/LKALt2F +35D7/qNU9ZWz8qLn2PaSn+DnukNwjk4D7xvwX4SljChxYUbCtOOSPBCK7HTHaBY yAM6J5eZsJik4exahP8mkGW6zPIf70eDL8cLhEF+HMWJEcj/srYeQbEeYgYU6f3G tKVccnrbJ8fHuIrZceOSFbN0b2RXzp+nJ+PD7jiXVOxV8inWXooyEJnDfdXe484c Yue0bEVuciy79n1Z/WPDn6L6/Oi/K5lWal+EQN33w+67FXFBnxCBhh1NPtmJKovy olr5BAJMgVzG60rrOXZvREoJFKEUkTwFIw+VnFgxf0ryFfpaoGQ= =fJN3 -----END PGP SIGNATURE----- --BXVAT5kNtrzKuDFl--