From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1524739035; cv=none; d=google.com; s=arc-20160816; b=vQqU7WKJTrCeUt0J+iHh7fcmQ9tph27DXcegMu0sUTGOY6csAL9Hee1Pf/APc57FbN 6OPjFuAwzy/yUEfdpvLNtPpJ8LGymzVsAiGS6ebZvonH2T11waZ+zVVVmbcISzdhpKP8 layFky/xor7QLAsgGQUh6y/PwK3/I9ofEUInBrmjk74uyrrHVfUInwErhX4B48q7738z Yofehc4T8NFDqsjDg6XKXl9hjsRKQM/nmyn692+93f9WzUOr+8mOCD1E5m1d5G/NgBHq Pztpi076OxmpAuu6fdl+U9E+Hl9WjTl1uyNdX0zB2R2cDVFN2SF2ByshFn3OrPSLvApL 0h8A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature :arc-authentication-results; bh=ewsDL+aPyLfD5fkSnwohd0nQwbyJ74Ncf0kesK4il3w=; b=zWvqRfUIUEMADuf4k9K30DLu6wezh4iFJ4Q6D0jWKQJbnWbYlAVPs+KzB3elntL9Ko GQoq6ekG06tMyS63VRbFjF1pEBFlxuxMhSwlP18nH/wnESDk5Q2Ncd6XU+2oJmO0Igtb dsBbXKVBggex/fvA3AOqS+cCspEytvO5TF2nAt7BC4llFS13p+5XcSzON2rqpsGEqSee 8a+PGBmTyssbbTQZ3adJwfw2KE8+FHCrw/xckD3TyQ3C6Bg1eRDFbfERK1w4xSBPOASJ oZOSEBZGj7E4Mh2tz2PwRi3AHpbL1LOkdpca3m/VM7Qmm49jLZGa8Ppjx9IEDhII0UXU 4IHg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=fPlrQ5AR; spf=pass (google.com: domain of liuhangbin@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=liuhangbin@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=fPlrQ5AR; spf=pass (google.com: domain of liuhangbin@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=liuhangbin@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AIpwx48b6wKHW+ATRB6WwRxzWDOHJQ5gop2+NzFa4GtzqUZZi/1Cx6dEcpvsLfoFlyklZKwapicpAA== Date: Thu, 26 Apr 2018 18:37:03 +0800 From: Hangbin Liu To: Dmitry Vyukov Cc: syzbot , bridge@lists.linux-foundation.org, David Miller , LKML , netdev , stephen hemminger , syzkaller-bugs , Greg Kroah-Hartman Subject: Re: WARNING: kobject bug in br_add_if Message-ID: <20180426103702.GI20683@leo.usersys.redhat.com> References: <001a113de2d878ade40569941a21@google.com> <20180426061314.GH20683@leo.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.7.0 (2016-08-17) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcSW1wb3J0YW50Ig==?= X-GMAIL-THRID: =?utf-8?q?1597463513858460385?= X-GMAIL-MSGID: =?utf-8?q?1598804758806402977?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, Apr 26, 2018 at 10:04:16AM +0200, Dmitry Vyukov wrote: > On Thu, Apr 26, 2018 at 8:13 AM, Hangbin Liu wrote: > > On Wed, Apr 11, 2018 at 05:18:23PM +0200, Dmitry Vyukov wrote: > >> On Wed, Apr 11, 2018 at 5:15 PM, syzbot > >> wrote: > >> > Hello, > >> > > >> > syzbot hit the following crash on upstream commit > >> > 10b84daddbec72c6b440216a69de9a9605127f7a (Sat Mar 31 17:59:00 2018 +0000) > >> > Merge branch 'perf-urgent-for-linus' of > >> > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip > >> > syzbot dashboard link: > >> > https://syzkaller.appspot.com/bug?extid=de73361ee4971b6e6f75 > >> > > >> > So far this crash happened 4 times on net-next, upstream. > >> > Unfortunately, I don't have any reproducer for this crash yet. > >> > Raw console output: > >> > https://syzkaller.appspot.com/x/log.txt?id=5007286875455488 > >> > Kernel config: > >> > https://syzkaller.appspot.com/x/.config?id=-2760467897697295172 > >> > compiler: gcc (GCC) 7.1.1 20170620 > >> > > >> > IMPORTANT: if you fix the bug, please add the following tag to the commit: > >> > Reported-by: syzbot+de73361ee4971b6e6f75@syzkaller.appspotmail.com > >> > It will help syzbot understand when the bug is fixed. See footer for > >> > details. > >> > If you forward the report, please keep this part and the footer. > >> > >> +Greg > >> > >> The plan is to remove this WARNING from kobject_add, if there are no objections. > > > > Hi Dmitry, > > > > For this bug, why should we remove the WARNING instead of adding a check in > > br_add_if()? Something like > > > Mainline because nobody wants to fix these. > If you think this is a real bug and you are ready to fix it, please > mail an official patch. > > >> > ------------[ cut here ]------------ > >> > binder: 23650:23651 unknown command 1078223622 > >> > kobject_add_internal failed for brport (error: -12 parent: bond0) Re-checked the error. This is a -ENOMEM. So normally we could ignore it. But on the other hand, although we could find out the slave iface's master in netdev_master_upper_dev_link(). It already go much further and allocate some resource and change iface state. e.g. [54273.968516] br0: port 1(em1) entered blocking state [54273.973979] br0: port 1(em1) entered disabled state So I think we'd better return as early as possible. I will post a fix for this. Thanks Hangbin > >> > binder: 23650:23651 ioctl c0306201 2000dfd0 returned -22 > >> > WARNING: CPU: 1 PID: 23647 at lib/kobject.c:242 > >> > kobject_add_internal+0x3f6/0xbc0 lib/kobject.c:240 > >> > Kernel panic - not syncing: panic_on_warn set ... > >> > > >> > CPU: 1 PID: 23647 Comm: syz-executor7 Not tainted 4.16.0-rc7+ #374 > >> > binder: BINDER_SET_CONTEXT_MGR already set > >> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > >> > Google 01/01/2011 > >> > Call Trace: > >> > __dump_stack lib/dump_stack.c:17 [inline] > >> > dump_stack+0x194/0x24d lib/dump_stack.c:53 > >> > panic+0x1e4/0x41c kernel/panic.c:183 > >> > __warn+0x1dc/0x200 kernel/panic.c:547 > >> > report_bug+0x1f4/0x2b0 lib/bug.c:186 > >> > fixup_bug.part.10+0x37/0x80 arch/x86/kernel/traps.c:178 > >> > fixup_bug arch/x86/kernel/traps.c:247 [inline] > >> > do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 > >> > do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 > >> > invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986 > >> > RIP: 0010:kobject_add_internal+0x3f6/0xbc0 lib/kobject.c:240 > >> > RSP: 0018:ffff8801d089f560 EFLAGS: 00010286 > >> > RAX: dffffc0000000008 RBX: ffff8801adbee178 RCX: ffffffff815b193e > >> > RDX: 0000000000040000 RSI: ffffc900022aa000 RDI: 1ffff1003a113e31 > >> > RBP: ffff8801d089f658 R08: 1ffff1003a113df3 R09: 0000000000000000 > >> > R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a113eb2 > >> > R13: 00000000fffffff4 R14: ffff8801abd88828 R15: ffff8801d75a1e00 > >> > kobject_add_varg lib/kobject.c:364 [inline] > >> > kobject_init_and_add+0xf9/0x150 lib/kobject.c:436 > >> > br_add_if+0x79a/0x1a70 net/bridge/br_if.c:533 > >> > add_del_if+0xf4/0x140 net/bridge/br_ioctl.c:101 > >> > br_dev_ioctl+0xa2/0xc0 net/bridge/br_ioctl.c:396 > >> > dev_ifsioc+0x333/0x9b0 net/core/dev_ioctl.c:334 > >> > dev_ioctl+0x176/0xbe0 net/core/dev_ioctl.c:500 > >> > sock_do_ioctl+0x1ba/0x390 net/socket.c:981 > >> > sock_ioctl+0x367/0x670 net/socket.c:1081 > >> > vfs_ioctl fs/ioctl.c:46 [inline] > >> > do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 > >> > SYSC_ioctl fs/ioctl.c:701 [inline] > >> > SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 > >> > do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 > >> > entry_SYSCALL_64_after_hwframe+0x42/0xb7 > >> > RIP: 0033:0x454e79 > >> > RSP: 002b:00007eff7dab7c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > >> > RAX: ffffffffffffffda RBX: 00007eff7dab86d4 RCX: 0000000000454e79 > >> > RDX: 0000000020000000 RSI: 00000000000089a2 RDI: 0000000000000014 > >> > RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 > >> > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000015 > >> > R13: 0000000000000369 R14: 00000000006f7278 R15: 0000000000000006 > >> > Dumping ftrace buffer: > >> > (ftrace buffer empty) > >> > Kernel Offset: disabled > >> > Rebooting in 86400 seconds..