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Subject: Re: [PATCH 3.16 23/99] tty/ldsem: Wake up readers after timed out
 down_write()
To:     Ben Hutchings <ben@decadent.org.uk>
Cc:     open list <linux-kernel@vger.kernel.org>,
        stable <stable@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Denis Kirjanov <kda@linux-powerpc.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>,
        kernel test robot <rong.a.chen@intel.com>,
        Dmitry Safonov <dima@arista.com>,
        Peter Zijlstra <peterz@infradead.org>
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 <0fb333560ad4ed9d5c8bc0f71a46fee5b448f9e6.camel@decadent.org.uk>
From:   Dmitry Safonov <0x7f454c46@gmail.com>
Message-ID: <2aa7996d-708a-b6b9-3197-94814b708881@gmail.com>
Date:   Tue, 2 Apr 2019 15:39:15 +0100
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On 4/2/19 3:32 PM, Ben Hutchings wrote:
> On Tue, 2019-04-02 at 15:22 +0100, Dmitry Safonov wrote:
>> Hi Ben,
>>
>> JFI: I haven't checked your tree, but the same patches set contains fixes
>> that are more important to my mind (looking at 4.9 stable tree):
>> - "tty: Drop tty->count on tty_reopen() failure" commit fe3241679009
> 
> You marked this as applicable to 4.6+.  Is it actually applicable to
> older versions as well?

Oh, probably you're right - I'll need to look at the v3.16 source to
tell better. I think, I've marked the proper version at that time.

> 
>> - "tty: Hold tty_ldisc_lock() during tty_reopen()" commit 83d817f41070
>>   with follow-up fixup "tty: Don't hold ldisc lock in tty_reopen() if
>> ldisc present"
>>   commit d3736d82e816
> [...]
> 
> I will include these in a later update, unless you think they are
> really urgent and should be added to this one.

Well, I thought worth to mention those patches, but in reality haven't
checked if they are applicable to v3.16.
It's just I remember "tty: Hold tty_ldisc_lock() during tty_reopen()"
was the main fix in the set, as many people suffered from issue under
it, so I thought strange that only a side-patch (which can lead to soft
lockup, so probably also important) is ported. But I managed to forget
that the code has changes since v3.16.

Thanks,
          Dmitry