leak is only reported about 1/2 of runs

The attached program always leaks a malloc.  However, the leak is not always 
reported.  See expected output section.

What steps will reproduce the problem?
1. make check
2. make check
3. make check

What is the expected output? What do you see instead?

rfp@sebastian:~/src/asan.sometimes.leaks$ make check
clang-3.5 -g -fsanitize=address -O0 -fno-omit-frame-pointer -o leak leak.c 
clang-3.5 --version
Ubuntu clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on 
LLVM 3.5.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
./leak

=================================================================
==31259==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 1 byte(s) in 1 object(s) allocated from:
    #0 0x49a88b in __interceptor_malloc (/home/rfp/src/asan.sometimes.leaks/leak+0x49a88b)
    #1 0x4b8218 in main /home/rfp/src/asan.sometimes.leaks/leak.c:4:15
    #2 0x2b20fb394ec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287

SUMMARY: AddressSanitizer: 1 byte(s) leaked in 1 allocation(s).
make: *** [check] Error 23
rfp@sebastian:~/src/asan.sometimes.leaks$ make check
clang-3.5 --version
Ubuntu clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on 
LLVM 3.5.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
./leak
rfp@sebastian:~/src/asan.sometimes.leaks$ make check
clang-3.5 --version
Ubuntu clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on 
LLVM 3.5.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
./leak

=================================================================
==31268==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 1 byte(s) in 1 object(s) allocated from:
    #0 0x49a88b in __interceptor_malloc (/home/rfp/src/asan.sometimes.leaks/leak+0x49a88b)
    #1 0x4b8218 in main /home/rfp/src/asan.sometimes.leaks/leak.c:4:15
    #2 0x2b4d14b3eec4 in __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:287

SUMMARY: AddressSanitizer: 1 byte(s) leaked in 1 allocation(s).
make: *** [check] Error 23
rfp@sebastian:~/src/asan.sometimes.leaks$ make check
clang-3.5 --version
Ubuntu clang version 3.5.0-4ubuntu2~trusty2 (tags/RELEASE_350/final) (based on 
LLVM 3.5.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
./leak

What version of the product are you using? On what operating system?

ubuntu 14.04
clang-3.5

Please provide any additional information below.
Original issue reported on code.google.com by prohas...@gmail.com on 20 Aug 2015 at 6:55
Attachments:
lsalamon / address-sanitizer

leak is only reported about 1/2 of runs #406
