[uclibc-ng-devel] [PATCH] Fix _dl_deallocate_tls in !SHARED case

Yann Sionneau ysionneau at kalray.eu
Tue Apr 9 13:00:43 CEST 2019


This patch seems needed in builds where
- SHARED is not defined (no shared lib support)
- and USE_TLS is set

Without this patch, static_dtv is free'ed.
See the following backtrace:

This backtrace is obtained while debugging tst-basic3 from the uclibc-ng nptl testsuite.
It aborts because of the assert in malloc:
https://elixir.bootlin.com/uclibc-ng/v1.0.31/source/libc/stdlib/malloc-standard/malloc.c#L80

Signed-off-by: Yann Sionneau <ysionneau at kalray.eu>
---
 libpthread/nptl/sysdeps/generic/dl-tls.c   | 5 +++++
 libpthread/nptl/sysdeps/generic/libc-tls.c | 5 ++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/libpthread/nptl/sysdeps/generic/dl-tls.c b/libpthread/nptl/sysdeps/generic/dl-tls.c
index 989e587a2..7d25e4706 100644
--- a/libpthread/nptl/sysdeps/generic/dl-tls.c
+++ b/libpthread/nptl/sysdeps/generic/dl-tls.c
@@ -48,6 +48,9 @@
 /* Value used for dtv entries for which the allocation is delayed.  */
 # define TLS_DTV_UNALLOCATED	((void *) -1l)
 
+#ifndef SHARED
+extern dtv_t static_dtv;
+#endif
 
 /* Out-of-memory handler.  */
 # ifdef SHARED
@@ -584,6 +587,8 @@ _dl_deallocate_tls (void *tcb, bool dealloc_tcb)
   /* The array starts with dtv[-1].  */
 #ifdef SHARED
   if (dtv != GL(dl_initial_dtv))
+#else
+  if ((dtv - 1) != &static_dtv)
 #endif
     free (dtv - 1);
 
diff --git a/libpthread/nptl/sysdeps/generic/libc-tls.c b/libpthread/nptl/sysdeps/generic/libc-tls.c
index a6df4cdc4..d746c9a38 100644
--- a/libpthread/nptl/sysdeps/generic/libc-tls.c
+++ b/libpthread/nptl/sysdeps/generic/libc-tls.c
@@ -42,7 +42,10 @@ extern size_t _dl_phnum;
 extern int __tdata_start;
 #endif
 
-static dtv_t static_dtv[2 + TLS_SLOTINFO_SURPLUS];
+#ifdef SHARED
+static
+#endif
+dtv_t static_dtv[2 + TLS_SLOTINFO_SURPLUS];
 
 
 static struct
-- 
2.21.0



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