885336 - Make SPS on Android work with MOZ_LINKER_EXTRACT=1

Status: RESOLVED FIXED

(Core :: Gecko Profiler, defect)

Description

[Julian Seward [:jseward]]

Currently SPS/Breakpad on Android only works for the non-MOZ_LINKER_EXTRACT
(default) mode.  That's OK for production use but defeats use of Valgrind
for Fennec for the profiler, since V currently requires MOZ_LINKER_EXTRACT=1
to work (basically at all).

The problem is that SPS requests faulty.lib to provide libxul/libmozalloc/libnss
from the .APK, but in unpack mode they are instead in $libdir/cache, and so
SPS fails to read any unwind information for those libraries, making native
unwinding unusable.

Comment 1

[Julian Seward [:jseward]]

Attachment: Patch

Comment 2

[Mike Hommey [:glandium] (high latency)]

Comment on attachment 765368 [details] [diff] [review]
Patch

Review of attachment 765368 [details] [diff] [review]:
-----------------------------------------------------------------

faulty.lib ought to handle this itself. It should already, but if it doesn't, it's something to fix in faulty.lib. Not in the caller.

Comment 3

[Julian Seward [:jseward]]

(In reply to Mike Hommey (high latency until June 25) [:glandium] from comment #2)
> faulty.lib ought to handle this itself. It should already, but if it
> doesn't, it's something to fix in faulty.lib. Not in the caller.

Ok, but .. that would make it inconsistent with what's currently in 
local_debug_info_symbolizer.cc, no?  It already special-cases
the handling of libmozglue.so.

Comment 4

[Mike Hommey [:glandium] (high latency)]

libmozglue.so is not loaded by faulty.lib, as it contains it.

Comment 5

[Mike Hommey [:glandium] (high latency)]

Attachment: Make the dl_mmap interface from bug 802240 work with MOZ_LINKER_EXTRACT

I think this will solve your issue.

Comment 6

[Julian Seward [:jseward]]

So .. I'm not clear whether the above patch just makes __dl_mmap work,
or whether it also fixes __dl_get_mappable_length.  I ask because with
it in place, I get this:

E/Profiler(30027): 2013-06-25 22:19:47: local_debug_info_symbolizer.cc:121: INFO: ReadSymbolData_APK: Unable to get size for ELF file '/data/app/org.mozilla.fennec-1.apk!/assets/libxul.so'

and the same for libmozalloc.so and libnss3.so.

so it kinda seems like __dl_get_mappable_length is failing.

Comment 7

[Mike Hommey [:glandium] (high latency)]

Attachment: Fix various issues with the dl_mmap interface

Julian, can you test this patch?

Comment 8

[Mike Hommey [:glandium] (high latency)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/c4abdcc3451c

Comment 9

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/c4abdcc3451c