Messages in this thread | | | Date | Mon, 10 Mar 2014 15:23:06 -0400 | From | Peter Hurley <> | Subject | Re: pppd service crash in linux-3.13.6 |
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[ +cc Oleg Nesterov ]
On 03/10/2014 12:56 PM, Sree Harsha Totakura wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi, > > Using linux-3.13.6, I am observing the following output from the pppd > kernel thread. This happens when I try to suspend my computer and it > *stops* the computer from suspending. > > I am using ppp via a bluetooth modem. > > Trace: > [22735.115313] PM: Syncing filesystems ... done. > [22735.665613] PM: Preparing system for mem sleep > [22735.665829] Freezing user space processes ... > [22755.659538] Freezing of tasks failed after 20.004 seconds (1 tasks > refusing to freeze, wq_ > busy=0): > [22755.659555] pppd D ffff8800376c9a58 0 16801 1 > 0x00000006 > [22755.659557] ffff8800376c9750 0000000000000046 0000000000012e80 > 0000000000012e80 > [22755.659560] ffff8802a1c1dfd8 ffff8800376c9750 0000000000000009 > ffff8802a1c1dd78 > [22755.659562] 0000000000000046 ffff8800376c9750 0000000000000028 > ffff8800376c9750 > [22755.659564] Call Trace: > [22755.659569] [<ffffffff81048507>] ? do_exit+0x937/0xa50 > [22755.659573] [<ffffffff814bb6e1>] ? oops_end+0x91/0xd0 > [22755.659575] [<ffffffff814b1f4f>] ? no_context+0x1f3/0x1ff > [22755.659577] [<ffffffff814bdb69>] ? __do_page_fault+0x89/0x500 > [22755.659581] [<ffffffff811017dc>] ? free_pcppages_bulk+0x17c/0x3b0 > [22755.659584] [<ffffffff81101cce>] ? free_hot_cold_page_list+0x3e/0x90 > [22755.659586] [<ffffffff814babf8>] ? page_fault+0x28/0x30 > [22755.659591] [<ffffffffa06fd5a3>] ? ppp_register_channel+0x13/0x20 > [ppp_generic] > [22755.659594] [<ffffffffa07062ab>] ? ppp_asynctty_open+0x12b/0x170 > [ppp_async] > [22755.659596] [<ffffffff812ec907>] ? tty_ldisc_open.isra.2+0x27/0x60 > [22755.659598] [<ffffffff812ed1d3>] ? tty_ldisc_hangup+0x1e3/0x220 > [22755.659601] [<ffffffff812e4614>] ? __tty_hangup+0x2c4/0x440 > [22755.659603] [<ffffffff812e56a1>] ? disassociate_ctty+0x61/0x270 > [22755.659605] [<ffffffff810483c2>] ? do_exit+0x7f2/0xa50 > [22755.659607] [<ffffffff81053ad2>] ? recalc_sigpending+0x12/0x50 > [22755.659609] [<ffffffff81054308>] ? __set_task_blocked+0x28/0x70 > [22755.659611] [<ffffffff81048684>] ? do_group_exit+0x34/0xa0 > [22755.659613] [<ffffffff810486fb>] ? SyS_exit_group+0xb/0x10 > [22755.659615] [<ffffffff814c1eb9>] ? system_call_fastpath+0x16/0x1b > [22755.659618] > [22755.659619] Restarting tasks ... done. > > If you need any more info, I am happy to provide.
The NULL ptr dereference is from following the current->nsproxy ptr in ppp_register_channel().
This was broken by
commit 8aac62706adaaf0fab02c4327761561c8bda9448 Author: Oleg Nesterov <oleg@redhat.com> Date: Fri Jun 14 21:09:49 2013 +0200
move exit_task_namespaces() outside of exit_notify()
which moved the exit_task_namespaces(tsk) before disassociate_ctty().
Regards, Peter Hurley
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