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authorCarlos O'Donell <carlos@redhat.com>2017-12-12 20:35:05 -0800
committerCarlos O'Donell <carlos@redhat.com>2017-12-15 20:22:29 -0800
commit93930ea9351c0c4a239e3dcb83f1398cce4e4d43 (patch)
treedc38ac46edbdc3ec877fa7e12194daba7a1d6b2b /elf
parent9d7a3741c9e59eba87fb3ca6b9f979befce07826 (diff)
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Fix tst-leaks1 (bug 14681)
The test tst-leaks1 exercises calling dlopen with a $ORIGIN DST. This results in a theoretical leak e.g. Memory not freed: ----------------- Address Size Caller 0x0000000001d766c0 0x21 at 0x7fb1bd8bf4ab Or as seen via valgrind: ==27582== 33 bytes in 1 blocks are still reachable in loss record 1 of 1 ==27582== at 0x4C2CB6B: malloc (vg_replace_malloc.c:299) ==27582== by 0x40124AA: _dl_get_origin (dl-origin.c:50) ==27582== by 0x4007DB9: expand_dynamic_string_token (dl-load.c:382) ==27582== by 0x400899C: _dl_map_object (dl-load.c:2160) ==27582== by 0x4013020: dl_open_worker (dl-open.c:224) ==27582== by 0x5166F9B: _dl_catch_exception (dl-error-skeleton.c:198) ==27582== by 0x4012BD9: _dl_open (dl-open.c:594) ==27582== by 0x4E39EF5: dlopen_doit (dlopen.c:66) ==27582== by 0x5166F9B: _dl_catch_exception (dl-error-skeleton.c:198) ==27582== by 0x516700E: _dl_catch_error (dl-error-skeleton.c:217) ==27582== by 0x4E3A514: _dlerror_run (dlerror.c:162) ==27582== by 0x4E39F70: dlopen@@GLIBC_2.2.5 (dlopen.c:87) There is no real leak. The calling link map (the executable's link map) has it's l_origin expanded for future use as part of _dl_get_origin, and that results in the main executable link map having a N-byte allocation for l->l_origin that is never freed since the executable's link map is just a part of the process. To take this into account we do one dlopen with $ORIGIN before calling mtrace to force the initialization of the executable link map. Signed-off-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'elf')
-rw-r--r--elf/tst-leaks1.c21
1 files changed, 18 insertions, 3 deletions
diff --git a/elf/tst-leaks1.c b/elf/tst-leaks1.c
index d67e826..75bc92d 100644
--- a/elf/tst-leaks1.c
+++ b/elf/tst-leaks1.c
@@ -6,13 +6,28 @@
static int
do_test (void)
{
+ void *h;
+ int ret = 0;
+ /* Carry out *one* failing call to dlopen before starting mtrace to
+ force any one-time inintialization that may happen to the
+ executable link map e.g. expansion and caching of $ORIGIN. */
+ h = dlopen ("$ORIGIN/tst-leaks1.o", RTLD_LAZY);
+ if (h != NULL)
+ {
+ puts ("dlopen unexpectedly succeeded");
+ ret = 1;
+ dlclose (h);
+ }
+
+ /* Start tracing and run each test 5 times to see if there are any
+ leaks in the failing dlopen. */
mtrace ();
- int ret = 0;
for (int i = 0; i < 10; i++)
{
- void *h = dlopen (i < 5 ? "./tst-leaks1.c"
- : "$ORIGIN/tst-leaks1.o", RTLD_LAZY);
+ h = dlopen (i < 5
+ ? "./tst-leaks1.c"
+ : "$ORIGIN/tst-leaks1.o", RTLD_LAZY);
if (h != NULL)
{
puts ("dlopen unexpectedly succeeded");