Messages in this thread | | | Date | Sun, 6 May 2018 13:17:51 -0700 | From | Greg KH <> | Subject | Re: BUG: soft lockup in commit_echoes |
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On Sun, May 06, 2018 at 09:27:02AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on:
Meta comment on the format of all of this:
> > HEAD commit: c1c07416cdd4 Merge tag 'kbuild-fixes-v4.17' of git://git.k.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=138afde7800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5a1dc06635c10d27 > dashboard link: https://syzkaller.appspot.com/bug?extid=995c889cef82be5ccddf > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1355fc37800000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1033f657800000
First off, great job, that's a nice summary.
You might want to put the "dashboard link" at the top somewhere, it is burried in there and I totally missed it and wrote a long paragraph asking that you add something like that to this report, before I noticed that it was already there :)
> IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+995c889cef82be5ccddf@syzkaller.appspotmail.com
Nit, should you have < > around that email address?
> watchdog: BUG: soft lockup - CPU#0 stuck for 135s! [kworker/u4:3:4495] > Modules linked in: > irq event stamp: 916736 > hardirqs last enabled at (916735): [<ffffffff878009d5>] > restore_regs_and_return_to_kernel+0x0/0x2b > hardirqs last disabled at (916736): [<ffffffff87800905>] > interrupt_entry+0xb5/0xf0 arch/x86/entry/entry_64.S:625 > softirqs last enabled at (746274): [<ffffffff87a00778>] > __do_softirq+0x778/0xaf5 kernel/softirq.c:311 > softirqs last disabled at (746209): [<ffffffff81475281>] invoke_softirq > kernel/softirq.c:365 [inline] > softirqs last disabled at (746209): [<ffffffff81475281>] > irq_exit+0x1d1/0x200 kernel/softirq.c:405
As a script generates this, why is it being line-wrapped?
> CPU: 0 PID: 4495 Comm: kworker/u4:3 Not tainted 4.17.0-rc3+ #34 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: events_unbound flush_to_ldisc > RIP: 0010:echo_buf drivers/tty/n_tty.c:144 [inline] > RIP: 0010:__process_echoes+0x1fd/0x8d0 drivers/tty/n_tty.c:733 > RSP: 0018:ffff8801adbc7268 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 > RAX: ffff8801ad126280 RBX: 00000001fda8cfee RCX: ffffffff8397b54c > RDX: 0000000000000000 RSI: ffffffff8397b46d RDI: 0000000000000001 > RBP: ffff8801adbc72d0 R08: ffff8801ad126280 R09: 0000000000000006 > R10: ffff8801ad126280 R11: 0000000000000000 R12: ffffc90001eec000 > R13: 0000000000001a02 R14: 00000001fda8cfef R15: 00000000000000ff > FS: 0000000000000000(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000021000000 CR3: 00000001ada40000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > commit_echoes+0x163/0x1d0 drivers/tty/n_tty.c:764 > n_tty_receive_char_fast drivers/tty/n_tty.c:1416 [inline] > n_tty_receive_buf_fast drivers/tty/n_tty.c:1576 [inline] > __receive_buf drivers/tty/n_tty.c:1611 [inline] > n_tty_receive_buf_common+0x2048/0x2c50 drivers/tty/n_tty.c:1709 > n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1744 > tty_ldisc_receive_buf+0xb0/0x190 drivers/tty/tty_buffer.c:456 > tty_port_default_receive_buf+0x110/0x170 drivers/tty/tty_port.c:38 > receive_buf drivers/tty/tty_buffer.c:475 [inline] > flush_to_ldisc+0x3e9/0x560 drivers/tty/tty_buffer.c:524 > 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 > Code: 48 83 c3 01 48 b9 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 08 00 0f > 85 17 06 00 00 4d 8b 6c 24 20 e9 db fe ff ff e8 73 7b e1 fd <41> 81 e6 ff 0f > 00 00 48 b9 00 00 00 00 00 fc ff df 4b 8d bc 34
Anyway, keep up the great work, I'll add this to my every-growing list of stuff to look at...
greg k-h
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