From: Martin Fuzzey <mfuzzey-mB3Nsq4MPf1BDgjK7y7TUQ@public.gmane.org>
To: "Luis R. Rodriguez" <mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Linux FS Devel
<linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Alan Cox <alan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
Ted Ts'o <tytso-3s7WtUTddSA@public.gmane.org>,
Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Dmitry Torokhov
<dmitry.torokhov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"Michael Kerrisk (man-pages)"
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Greg KH
<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
Daniel Wagner <wagi-kQCPcA+X3s7YtjvyW6yDsg@public.gmane.org>,
David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
jewalt-d4N2ExZK1jaSe5ORCPIMD9BPR1lH4CV8@public.gmane.org,
rafal-g1n6cQUeyibVItvQsEIGlw@public.gmane.org,
Arend Van Spriel
<arend.vanspriel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>,
"Rafael J. Wysocki" <rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>,
"Li, Yi" <yi1.li-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org,
Moritz Fischer
<moritz.fischer-+aYTwkv1SeIAvxtiuMwx3w@public.gmane.org>,
Petr Mladek <pmladek-IBi9RG/b67k@public.gmane.org>,
Johannes Berg
<johannes.berg-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
Emmanuel
Subject: Re: [PATCH v2] firmware: fix sending -ERESTARTSYS due to signal on fallback
Date: Fri, 9 Jun 2017 09:40:47 +0200 [thread overview]
Message-ID: <593A50FF.40604@parkeon.com> (raw)
In-Reply-To: <CAB=NE6UQZMmLvxTu7RcFHh3neAh+RFpTTFCSwJ8_EsmmtEq94Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On 09/06/17 03:57, Luis R. Rodriguez wrote:
> On Thu, Jun 8, 2017 at 6:10 PM, Luis R. Rodriguez <mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:
>>> Android didn't send the signal, the kernel did (SIGCHLD).
>>>
>>> Like this:
>>>
>>> 1) Android init (pid=1) fork()s (say pid=42) [this child process is totally
>>> unrelated to firmware loading]
>>> 2) Android init (pid=1) does a write() on a (driver custom) sysfs file which
>>> ends up calling request_firmware() kernel side
>>> 3) The firmware loading fallback mechanism is used, the request is sent to
>>> userspace and pid 1 waits in the kernel on wait_*
>>> 4) before firmware loading completes pid 42 dies (for any reason - in my
>>> case normal termination)
> Martin just to be clear, by "normal case termination" do you mean
> completing successfully ?? Ie the firmware actually did make it onto
> the device ?
The firmware did *not* make it onto the device since the
request_firmware() call returned an error
(the code that would have transfered it to the device is only executed
following a successful request_firmware)
The process that terminates normally is unrelated to firmware loading as
I said above.
The only things that matter are:
- It is a child process of the process that calls request_firmware()
- It terminates *while* the the wait_ is still in progress
Here is a way of reproducing the problem using the test_firmware module
(which I only just saw) on normal linux with no Android or custom driver
#!/bin/sh
set -e
# Make sure the system firmware loader doesn't get in the way
/etc/init.d/udev stop
modprobe test_firmware
DIR=/sys/devices/virtual/misc/test_firmware
echo 10 >/sys/class/firmware/timeout;
sleep 2 &
echo -n "/some/non/existing/file.bin" > "$DIR"/trigger_request;
If run with the "sleep 2 &" it terminates after 2 seconds
If the sleep is commented it runs for the expected 10 seconds (the
firmware loading timeout)
Since the sleep process is a child of the script process requesting a
firmware load its death causes a SIGCHLD causing request_firmware() to
abort prematurely.
Martin
next prev parent reply other threads:[~2017-06-09 7:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170524205658.GK8951@wotan.suse.de>
[not found] ` <20170524214027.7775-1-mcgrof@kernel.org>
[not found] ` <CALCETrXUrirO-vg3M+MGhn=0gZTwx0phsRDS4TCwWWgNYC6RsA@mail.gmail.com>
2017-05-24 22:38 ` [PATCH v2] firmware: fix sending -ERESTARTSYS due to signal on fallback Luis R. Rodriguez
2017-05-25 4:13 ` Andy Lutomirski
[not found] ` <CALCETrU4__YUGk36PN=FbuEf0SBaTrxQQqm4sWs2NrZ+6WN7jA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-25 8:28 ` Fuzzey, Martin
2017-05-26 11:09 ` Eric W. Biederman
[not found] ` <87fufr3mdy.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-05-26 19:46 ` Luis R. Rodriguez
2017-05-26 21:26 ` Dmitry Torokhov
[not found] ` <CAKdAkRTrcTVOAP5GK-R=Au_tL5WqSn5UkQEzNe5NcCWXS8mbtA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-26 21:32 ` Luis R. Rodriguez
2017-05-26 21:55 ` Dmitry Torokhov
2017-06-05 20:24 ` Luis R. Rodriguez
[not found] ` <20170605202410.GQ8951-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-06-06 9:04 ` Martin Fuzzey
[not found] ` <59367025.3020901-mB3Nsq4MPf1BDgjK7y7TUQ@public.gmane.org>
2017-06-06 16:34 ` Luis R. Rodriguez
[not found] ` <20170606163401.GA27288-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-06-06 17:52 ` Luis R. Rodriguez
2017-06-06 14:53 ` Alan Cox
[not found] ` <1496760796.5682.48.camel-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-06-06 16:47 ` Luis R. Rodriguez
[not found] ` <20170606164734.GB27288-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-06-06 17:54 ` Luis R. Rodriguez
2017-06-06 22:11 ` Theodore Ts'o
[not found] ` <20170606221151.ygoxqkwhhjsqw632-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2017-06-07 0:22 ` Luis R. Rodriguez
[not found] ` <20170607002237.GJ27288-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-06-07 4:56 ` Andy Lutomirski
2017-06-07 6:25 ` Dmitry Torokhov
2017-06-07 12:25 ` Alan Cox
2017-06-07 17:15 ` Luis R. Rodriguez
2017-06-09 1:14 ` Andy Lutomirski
[not found] ` <CALCETrXbHpkN9Pujj=U1VpAR9MTOyCAqCtL0=7-vb1EdpEwCMg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-09 1:33 ` Luis R. Rodriguez
[not found] ` <CAB=NE6USSj0sBzJSFOyyRQu=0rQXdbHc2+GNk1fse+Y8H6TrgQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-09 21:29 ` Luis R. Rodriguez
[not found] ` <CANh8QzwPb_+RKs5QVt7mdFk8h_rOMVS3j9m0OADgvzBtNqBBLg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-26 19:40 ` Luis R. Rodriguez
[not found] ` <20170526194001.GR8951-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-05-26 20:23 ` Fuzzey, Martin
[not found] ` <CANh8QzyqQ5hubWJvWYxgoQ3baL6sgoQPSzEHMY0tu8WNGS2gZA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-05-26 20:52 ` Luis R. Rodriguez
2017-06-07 17:08 ` Luis R. Rodriguez
2017-06-07 17:54 ` Martin Fuzzey
[not found] ` <59383DDA.3040702-mB3Nsq4MPf1BDgjK7y7TUQ@public.gmane.org>
2017-06-09 1:10 ` Luis R. Rodriguez
2017-06-09 1:57 ` Luis R. Rodriguez
[not found] ` <CAB=NE6UQZMmLvxTu7RcFHh3neAh+RFpTTFCSwJ8_EsmmtEq94Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-09 7:40 ` Martin Fuzzey [this message]
[not found] ` <593A50FF.40604-mB3Nsq4MPf1BDgjK7y7TUQ@public.gmane.org>
2017-06-09 21:12 ` Luis R. Rodriguez
2017-06-09 22:55 ` Luis R. Rodriguez
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=593A50FF.40604@parkeon.com \
--to=mfuzzey-mb3nsq4mpf1bdgjk7y7tuq@public.gmane.org \
--cc=alan-VuQAYsv1563Yd54FQh9/CA@public.gmane.org \
--cc=arend.vanspriel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org \
--cc=atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org \
--cc=dmitry.torokhov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org \
--cc=gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org \
--cc=jewalt-d4N2ExZK1jaSe5ORCPIMD9BPR1lH4CV8@public.gmane.org \
--cc=johannes.berg-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org \
--cc=linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
--cc=mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org \
--cc=moritz.fischer-+aYTwkv1SeIAvxtiuMwx3w@public.gmane.org \
--cc=mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \
--cc=peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org \
--cc=pmladek-IBi9RG/b67k@public.gmane.org \
--cc=rafal-g1n6cQUeyibVItvQsEIGlw@public.gmane.org \
--cc=rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org \
--cc=tytso-3s7WtUTddSA@public.gmane.org \
--cc=wagi-kQCPcA+X3s7YtjvyW6yDsg@public.gmane.org \
--cc=yi1.li-VuQAYsv1563Yd54FQh9/CA@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).