On Wed, Apr 18, 2018 at 11:36 AM, Jan Kara <j...@suse.cz> wrote: > Hello, > > On Tue 17-04-18 18:02:02, syzbot wrote: >> syzbot hit the following crash on upstream commit >> a27fc14219f2e3c4a46ba9177b04d9b52c875532 (Mon Apr 16 21:07:39 2018 +0000) >> Merge branch 'parisc-4.17-3' of >> git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux >> syzbot dashboard link: >> https://syzkaller.appspot.com/bug?extid=e38306788a2e7102a3b6 >> >> syzkaller reproducer: >> https://syzkaller.appspot.com/x/repro.syz?id=5126465372815360 >> Raw console output: >> https://syzkaller.appspot.com/x/log.txt?id=5956756370882560 >> Kernel config: >> https://syzkaller.appspot.com/x/.config?id=-5914490758943236750 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+e38306788a2e7102a...@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. >> > > Removed binder messages from the lockup splat so that it's more readable.
These messages seems to be relevant and likely the root cause of the hang. +binder maintainers >> INFO: task kworker/u4:4:853 blocked for more than 120 seconds. >> Not tainted 4.17.0-rc1+ #6 >> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. >> kworker/u4:4 D11512 853 2 0x80000000 >> Workqueue: events_unbound fsnotify_mark_destroy_workfn >> Call Trace: >> context_switch kernel/sched/core.c:2848 [inline] >> __schedule+0x801/0x1e30 kernel/sched/core.c:3490 >> schedule+0xef/0x430 kernel/sched/core.c:3549 >> schedule_timeout+0x1b5/0x240 kernel/time/timer.c:1777 >> do_wait_for_common kernel/sched/completion.c:83 [inline] >> __wait_for_common kernel/sched/completion.c:104 [inline] >> wait_for_common kernel/sched/completion.c:115 [inline] >> wait_for_completion+0x3e7/0x870 kernel/sched/completion.c:136 >> __synchronize_srcu+0x189/0x240 kernel/rcu/srcutree.c:924 >> synchronize_srcu+0x408/0x54f kernel/rcu/srcutree.c:1002 >> fsnotify_mark_destroy_workfn+0x1aa/0x530 fs/notify/mark.c:759 >> process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 >> worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 >> kthread+0x345/0x410 kernel/kthread.c:238 >> ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > OK, so we are waiting for the grace period on fsnotify_mark_srcu. Seems > like someone is holding fsnotify_mark_srcu too long or srcu period cannot > finish for some other reason. However the reproducer basically contains > only one binder ioctl and I have no idea how that's connected with fsnotify > in any way. So either the reproducer is wrong, or binder is corrupting > memory and fsnotify is just a victim, or something like that... > > Honza > -- > Jan Kara <j...@suse.com> > SUSE Labs, CR > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/20180418093636.alasuzdjwjb2qovv%40quack2.suse.cz. > For more options, visit https://groups.google.com/d/optout.
