Re: [PATCHv2 2/4] tty: Hold tty_ldisc_lock() during tty_reopen()

[Jiri Slaby <jslaby@suse.com>]

On 09/04/2018, 03:51 AM, Sergey Senozhatsky wrote:
> On (09/03/18 17:52), Dmitry Safonov wrote:
>>
>> We've seen the following crash on v4.9.108 stable:
>>
>> BUG: unable to handle kernel paging request at 0000000000002260
>> IP: [..] n_tty_receive_buf_common+0x5f/0x86d
>> Workqueue: events_unbound flush_to_ldisc
>> Call Trace:
>>  [..] n_tty_receive_buf2
>>  [..] tty_ldisc_receive_buf
>>  [..] flush_to_ldisc
>>  [..] process_one_work
>>  [..] worker_thread
>>  [..] kthread
>>  [..] ret_from_fork
>>
>> tty_ldisc_reinit() should be called with ldisc_sem hold for writing,
>> which will protect any reader against line discipline changes.
>>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Jiri Slaby <jslaby@suse.com>
>> Cc: stable@vger.kernel.org # depends on commit b027e2298bd5 ("tty: fix
>> data race between tty_init_dev and flush of buf")
> 
> I believe there's a "Fixes" tag for that
> 
> Fixes: b027e2298bd5 ("tty: fix data race between tty_init_dev and flush of buf")
> Cc: stable@vger.kernel.org

Nope, it would be translated as:
Backport-first: b027e2298bd5
:)

thanks,
-- 
js
suse labs