If a shared library (so) is loaded using dlopen and utilizes thread-local storage (TLS), the memory will not be freed upon thread exit, resulting in a memory leak.
This issue has been resolved in glibc-2.14. However, it remains unresolved in uClibc.
The following patch is based on the patch made in glibc and has been validated as effective on the x86-64 architecture.
diff --git a/libpthread/nptl/allocatestack.c b/libpthread/nptl/allocatestack.c
index 7ef884543..941ef22f0 100644
--- a/libpthread/nptl/allocatestack.c
+++ b/libpthread/nptl/allocatestack.c
@@ -24,6 +24,7 @@
#include <unistd.h>
#include <sys/mman.h>
#include <sys/param.h>
+#include <dl-tls.h>
#include <tls.h>
#include <lowlevellock.h>
#include <link.h>
@@ -241,6 +242,10 @@ get_cached_stack (size_t *sizep, void **memp)
/* Clear the DTV. */
dtv_t *dtv = GET_DTV (TLS_TPADJ (result));
+ for (size_t cnt = 0; cnt < dtv[-1].counter; ++cnt)
+ if (! dtv[1 + cnt].pointer.is_static
+ && dtv[1 + cnt].pointer.val != TLS_DTV_UNALLOCATED)
+ free (dtv[1 + cnt].pointer.val);
memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t));
/* Re-initialize the TLS. */
diff --git a/libpthread/nptl/sysdeps/generic/dl-tls.c b/libpthread/nptl/sysdeps/generic/dl-tls.c
index 7d25e4706..7b7991be8 100644
--- a/libpthread/nptl/sysdeps/generic/dl-tls.c
+++ b/libpthread/nptl/sysdeps/generic/dl-tls.c
@@ -45,8 +45,6 @@
to allow dynamic loading of modules defining IE-model TLS data. */
# define TLS_STATIC_SURPLUS 64 + DL_NNS * 100
-/* Value used for dtv entries for which the allocation is delayed. */
-# define TLS_DTV_UNALLOCATED ((void *) -1l)
#ifndef SHARED
extern dtv_t static_dtv;
diff --git a/libpthread/nptl/sysdeps/x86_64/dl-tls.h b/libpthread/nptl/sysdeps/x86_64/dl-tls.h
index d6c338cda..5cac55f33 100644
--- a/libpthread/nptl/sysdeps/x86_64/dl-tls.h
+++ b/libpthread/nptl/sysdeps/x86_64/dl-tls.h
@@ -26,3 +26,6 @@ typedef struct
extern void *__tls_get_addr (tls_index *ti);
+
+/* Value used for dtv entries for which the allocation is delayed. */
+#define TLS_DTV_UNALLOCATED ((void *) -1l)
Ref:
https://sourceware.org/bugzilla/show_bug.cgi?id=12650
How to reproduce:
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