Miscompilation with gcc 4.8 (segfault in x264_cqm_init)
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
x264 (Ubuntu) |
Fix Released
|
High
|
Andrew Starr-Bochicchio | ||
Saucy |
Fix Released
|
High
|
Andrew Starr-Bochicchio |
Bug Description
SRU Justification:
[Impact]
* A segfault in libx264-123 has caused major regressions in vlc, kazam, avidemux, and avconv among others. Nearly any program that encodes video in H264 is probably affected.
[Test Case]
* As this impacts many packages, there are a number of possible test cases. A simple one is to use kazam, the screen recording app:
1) Install the kazam package.
2) Run kazam
3) Make sure "file > preferences > screencast > record with" is set to H264/MP4
4) Attempt to record a screencast.
With 2:0.123.
[Regression Potential]
* There is little chance of regression. In order to make the most minimal change possible, the package is just simply built with -fno-aggressive
[Other Info]
This had not been rebuilt with gcc 4.8 until one day before release when a rebuilt was triggered to fix the arm64 build.
http://
"GCC now uses a more aggressive analysis to derive an upper bound for the number of iterations of loops using constraints imposed by language standards. This may cause non-conforming programs to no longer work as expected, such as SPEC CPU 2006 464.h264ref and 416.gamess. A new option, -fno-aggressive
The fix has already been uploaded to trusty.
-------
Original bug:
Vlc crashes when encoding h264:
Thread 9 (Thread 0x7fffd9712700 (LWP 3034)):
#0 __memcmp_sse2 () at ../sysdeps/
#1 0x00007fffc9ec9d9e in x264_cqm_init () from /usr/lib/
#2 0x00007fffc9f34374 in x264_encoder_
#3 0x00007fffca1fef34 in Open (p_this=
#4 0x00007ffff795ed00 in vlc_module_load (p_this=
psz_
probe=
#5 0x00007ffff795f1a4 in module_need (obj=obj@
strict=
#6 0x00007fffe8ce8a34 in transcode_video_new (p_stream=
#7 0x00007fffe8ce9c28 in transcode_video_add (p_stream=
id=
#8 0x00007fffe8ce54a8 in Add (p_stream=
#9 0x00007ffff797f64f in sout_InputNew (p_sout=
at stream_
#10 0x00007ffff791b6e6 in DecoderProcessSout (p_block=0x0, p_dec=0x7fffe05
#11 DecoderProcess (p_dec=
#12 0x00007ffff791bde4 in DecoderThread (p_data=
#13 0x00007ffff76c8f6e in start_thread (arg=0x7fffd971
#14 0x00007ffff71ef9cd in clone () at ../sysdeps/
http://
Configure x264 with "--extra-
Also seems that problem solved in trunk - http://
Changed in x264 (Ubuntu Saucy): | |
status: | New → Triaged |
importance: | Undecided → High |
Changed in x264 (Ubuntu): | |
status: | Triaged → In Progress |
assignee: | nobody → Andrew Starr-Bochicchio (andrewsomething) |
Changed in x264 (Ubuntu Saucy): | |
status: | Triaged → In Progress |
assignee: | nobody → Andrew Starr-Bochicchio (andrewsomething) |
description: | updated |
Status changed to 'Confirmed' because the bug affects multiple users.