Bug 390498

Summary:	Valgrind reports errors without full backtrace on arm64
Product:	[Developer tools] valgrind	Reporter:	Reuben Thomas <rrt>
Component:	memcheck	Assignee:	Julian Seward <jseward>
Status:	REPORTED ---
Severity:	minor	CC:	tom
Priority:	NOR
Version:	3.13.0
Target Milestone:	---
Platform:	Android
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Reuben Thomas 2018-02-15 10:08:00 UTC

(Slightly surprised I didn't find anything about this by searching Bugzilla, so apologies if I've overlooked an existing bug.)

I get two main sorts of error:

==3230== 8 bytes in 1 blocks are definitely lost in loss record 1 of 5
==3230==    at 0x4A23B44: operator new(unsigned long) (in /data/data/com.termux/files/usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)

and:

==3374== Source and destination overlap in memcpy(0x4a20b20, 0x4a20b20, 80)
==3374==    at 0x4957724: memcpy (in /data/data/com.termux/files/usr/lib/valgrind/vgpreload_memcheck-arm64-linux.so)

As you can see, I'm using valgind in Termux, and indeed with the stock Termux package, in case that helps.

Comment 1 Reuben Thomas 2018-02-15 10:23:05 UTC

I'm sorry, I think I've misunderstood the logs: it's not reporting leaks etc. in vgpreload_memcheck-arm64-linux.so, it's that I would expect a further backtrace, but there isn't anything other than the lines I showed above. Still something odd going on…

Comment 2 Reuben Thomas 2018-02-15 10:25:26 UTC

I mean, specifically, no callers are listed (no "by" lines).

Comment 3 Tom Hughes 2018-02-15 10:43:08 UTC

That probably means you have stripped all the unwind information from vgpreload_memcheck-arm64-linux.so so valgrind is unable to unwind the stack to the next function.

Comment 4 Reuben Thomas 2018-02-15 10:46:55 UTC

As I said, it's a stock build. So looks like a problem with the Termux build, I'll investigate that. Thanks!

Comment 5 Reuben Thomas 2018-02-15 14:50:44 UTC

I've filed https://github.com/termux/termux-packages/issues/2148

Comment 6 Julian Seward 2018-08-06 08:42:25 UTC

(In reply to rrt from comment #5)
> I've filed https://github.com/termux/termux-packages/issues/2148

Hi!  I fixed some debuginfo reading stuff for arm64-linux recently
(within the past month) so it might be worth you trying the git
trunk, to see if this still happens.

Comment 7 Reuben Thomas 2018-08-06 09:37:28 UTC

Sorry, I didn't say that a rebuild fixed it; a Termux script (termux-elf-cleaner) used to remove some supposedly unneeded stuff from ELF binaries was found to be the culprit.