On Thu, Apr 26, 2018 at 10:04:16AM +0200, Dmitry Vyukov wrote: > On Thu, Apr 26, 2018 at 8:13 AM, Hangbin Liu <liuhang...@gmail.com> wrote: > > On Wed, Apr 11, 2018 at 05:18:23PM +0200, Dmitry Vyukov wrote: > >> On Wed, Apr 11, 2018 at 5:15 PM, syzbot > >> <syzbot+de73361ee4971b6e6...@syzkaller.appspotmail.com> 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+de73361ee4971b6e6...@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..
