On Wed, Apr 11, 2018 at 05:18:23PM +0200, Dmitry Vyukov wrote: > On Wed, Apr 11, 2018 at 5:15 PM, syzbot > <syzbot+de73361ee4971b6e6f75@xxxxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxx > > 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 diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index 82c1a6f..79dcc3d 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -518,8 +518,8 @@ int br_add_if(struct net_bridge *br, struct net_device *dev, return -ELOOP; } - /* Device is already being bridged */ - if (br_port_exists(dev)) + /* Device still has master upper dev */ + if (netdev_master_upper_dev_get(dev)) return -EBUSY; /* No bridging devices that dislike that (e.g. wireless) */ Thanks Hangbin > > > ------------[ cut here ]------------ > > binder: 23650:23651 unknown command 1078223622 > > kobject_add_internal failed for brport (error: -12 parent: bond0) > > 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..
