Dear Sean,
I'm no developer, but Google probably tell me to add the right flags:
root@testsub0
/var/tmp/portage/dev-vcs/subversion-1.14.5/work/subversion-1.14.5/testcase #
diff Makefile{.20250107-073455,} -u
--- Makefile.20250107-073455 2025-01-07 07:34:55.000000000 +0100
+++ Makefile 2025-01-07 07:59:56.481738320 +0100
@@ -1,5 +1,5 @@
-CFLAGS=-I/usr/include/apr-1.0
-LDFLAGS=-L/usr/lib/x86_64-linux-gnu
+CFLAGS=-I/usr/include/apr-1 -fsanitize=thread
+LDFLAGS=-L/usr/lib/x86_64-linux-gnu -fsanitize=thread
LDLIBS=-lapr-1
all: main
For the testcase, this catches problems:
root@testsub0
/var/tmp/portage/dev-vcs/subversion-1.14.5/work/subversion-1.14.5/testcase # ./main
n |& tail -50
Thread T3 (tid=58578, running) created by main thread at:
#0 pthread_create <null> (libtsan.so.2+0x39fe9)
#1 main <null> (main+0x1cb1)
Thread T2 (tid=58577, running) created by main thread at:
#0 pthread_create <null> (libtsan.so.2+0x39fe9)
#1 main <null> (main+0x1cb1)
SUMMARY: ThreadSanitizer: data race
(/var/tmp/portage/dev-vcs/subversion-1.14.5/work/subversion-1.14.5/testcase/main+0x1695)
in threadfunc
==================
==================
WARNING: ThreadSanitizer: data race (pid=58573)
Write of size 8 at 0x7b0400003848 by thread T1:
#0 threadfunc <null> (main+0x167e)
#1 <null> <null> (libtsan.so.2+0x34247)
Previous write of size 8 at 0x7b0400003848 by thread T10:
#0 threadfunc <null> (main+0x167e)
#1 <null> <null> (libtsan.so.2+0x34247)
As if synchronized via sleep:
#0 usleep <null> (libtsan.so.2+0x5acbd)
#1 threadfunc <null> (main+0x1794)
#2 <null> <null> (libtsan.so.2+0x34247)
Location is heap block of size 16 at 0x7b0400003840 allocated by thread T7:
#0 malloc <null> (libtsan.so.2+0x39137)
#1 threadfunc <null> (main+0x1532)
#2 <null> <null> (libtsan.so.2+0x34247)
Thread T1 (tid=58576, running) created by main thread at:
#0 pthread_create <null> (libtsan.so.2+0x39fe9)
#1 main <null> (main+0x1cb1)
Thread T10 (tid=58585, running) created by main thread at:
#0 pthread_create <null> (libtsan.so.2+0x39fe9)
#1 main <null> (main+0x1cb1)
Thread T7 (tid=58582, running) created by main thread at:
#0 pthread_create <null> (libtsan.so.2+0x39fe9)
#1 main <null> (main+0x1cb1)
SUMMARY: ThreadSanitizer: data race
(/var/tmp/portage/dev-vcs/subversion-1.14.5/work/subversion-1.14.5/testcase/main+0x167e)
in threadfunc
==================
ThreadSanitizer: reported 4 warnings
Creating mutex and threads... Done
Waiting for threads to finish... Finished
Checking for errors...
Thread 1 missing 0 found 4
Now, I'll try to apply this to the subversion Makefile and run the test suite...
On 07.01.25 05:11, Sean McBride wrote:
On 6 Jan 2025, at 16:32, Daniel Sahlberg wrote:
To me, this proves that my basic program is correct and that with a mutex, the
shared memory is protected and without the mutex we get errors. I have tested
this under both Ubuntu and Guix with the same results.
If you really want to prove correctness, build with thread sanitizer; that'll
help catch any race conditions.
Sean
