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Message-ID: <1491526031.2815.57.camel@neuling.org>
Subject: Re: tty crash in tty_ldisc_receive_buf()
From: Michael Neuling <mikey@neuling.org>
To: Rob Herring <robh@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>, Johan Hovold <johan@kernel.org>,
        Peter Hurley <peter@hurleysoftware.com>,
        Wang YanQing <udknight@gmail.com>,
        Alexander Popov <alex.popov@linux.com>,
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        Dmitry Vyukov <dvyukov@google.com>, benh <benh@kernel.crashing.org>,
        LKML <linux-kernel@vger.kernel.org>
Date: Fri, 07 Apr 2017 10:47:11 +1000
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> > If anyone has an idea, I'm happy to try a patch.
> 
> Can you try this one [1].

Rob, I'm still hitting it when I apply that on next-20170405. Crash below..

Any other clues?

[  229.422825] Unable to handle kernel paging request for data at address 0x00002260
[  229.423681] Faulting instruction address: 0xc0000000006fad80
cpu 0x13: Vector: 300 (Data Access) at [c00000799411f8a0]
    pc: c0000000006fad80: n_tty_receive_buf_common+0xc0/0xbd0
    lr: c0000000006fad5c: n_tty_receive_buf_common+0x9c/0xbd0
    sp: c00000799411fb20
   msr: 900000000280b033
   dar: 2260
 dsisr: 40000000
  current = 0xc0000079665d1e00
  paca    = 0xc00000000fb0be00	 softe: 0	 irq_happened: 0x01
    pid   = 5, comm = kworker/u56:0
Linux version 4.11.0-rc5-next-20170405+ (mikey@bml86) (gcc version 5.4.0
20160609 (Ubuntu/IBM 5.4.0-6ubuntu1~16.04.4) ) #4 SMP Thu Apr 6 19:13:58 CDT
2017
enter ? for help
[c00000799411fbf0] c0000000006ff968 tty_ldisc_receive_buf+0x48/0xe0
[c00000799411fc20] c0000000007009fc tty_port_default_receive_buf+0x2c/0x40
[c00000799411fc40] c000000000700278 flush_to_ldisc+0x168/0x190
[c00000799411fca0] c00000000010a0fc process_one_work+0x1ec/0x580
[c00000799411fd30] c00000000010a528 worker_thread+0x98/0x5d0
[c00000799411fdc0] c00000000011343c kthread+0x16c/0x1b0
[c00000799411fe30] c00000000000b4e8 ret_from_kernel_thread+0x5c/0x74
13:mon> r
R00 = c0000000006fad5c   R16 = 0000000000000000
R01 = c00000799411fb20   R17 = 0000000000000000
R02 = c0000000014b9200   R18 = c000007994060ea8
R03 = 0000000000000000   R19 = c000007994060c78
R04 = c0000000021c2420   R20 = c000007994060c20
R05 = c0000000021c2520   R21 = 0000000000000000
R06 = 0000000000000100   R22 = 0000000000000000
R07 = 0000000000000001   R23 = 0000000100000000
R08 = 0000000000000000   R24 = 0000000000000000
R09 = c0000000fc459600   R25 = 0000000000000000
R10 = c0000000fc459628   R26 = c0000000021c2420
R11 = 0002010100000005   R27 = c0000000021c2520
R12 = 0000000024002828   R28 = 0000000000000100
R13 = c00000000fb0be00   R29 = c0000000fc459400
R14 = c0000000001132d8   R30 = 0000000000000001
R15 = c0000079941f0ec0   R31 = c0000000fc459400
pc  = c0000000006fad80 n_tty_receive_buf_common+0xc0/0xbd0
cfar= c000000000b98e10 down_read+0x70/0x90
lr  = c0000000006fad5c n_tty_receive_buf_common+0x9c/0xbd0
msr = 900000000280b033   cr  = 24042828
ctr = c0000000006fb890   xer = 0000000000000000   trap =  300
dar = 0000000000002260   dsisr = 40000000