GNU C Library master sources branch master updated. glibc-2.25-221-g2604882

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- Log -----------------------------------------------------------------
http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=2604882cefd3281679b8177245fdebc7061b8695

commit 2604882cefd3281679b8177245fdebc7061b8695
Author: Rabin Vincent <rabinv@axis.com>
Date:   Mon Apr 17 12:03:44 2017 -0300

    [BZ 21357] unwind-dw2-fde: Call free() outside of unwind mutex
    
    __deregister_frame_info_bases() calls free() while holding a mutex which
    is also used from _Unwind_Find_FDE().  This leads to a deadlock if
    AddressSanitizer uses _Unwind_Backtrace() from its free()
    implementation.
    
    Checked on mips-linux-gnu and x86_64-linux-gnu.
    
    	[BZ #21357]
    	* sysdeps/generic/unwind-dw2-fde.c (__deregister_frame_info_bases):
    	Call free() outside of mutex.

diff --git a/ChangeLog b/ChangeLog
index b209f9c..bfda0e1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-04-17  Rabin Vincent  <rabinv@axis.com>
+
+	[BZ #21357]
+	* sysdeps/generic/unwind-dw2-fde.c (__deregister_frame_info_bases):
+	Call free() outside of mutex.
+
 2017-04-13  Florian Weimer  <fweimer@redhat.com>
 
 	* csu/check_fds.c (__libc_check_standard_fds): Assume O_NOFOLLOW
diff --git a/sysdeps/generic/unwind-dw2-fde.c b/sysdeps/generic/unwind-dw2-fde.c
index 2f0bcd2..104a255 100644
--- a/sysdeps/generic/unwind-dw2-fde.c
+++ b/sysdeps/generic/unwind-dw2-fde.c
@@ -202,6 +202,7 @@ __deregister_frame_info_bases (void *begin)
 {
   struct object **p;
   struct object *ob = 0;
+  struct fde_vector *tofree = NULL;
 
   /* If .eh_frame is empty, we haven't registered.  */
   if (*(uword *) begin == 0)
@@ -225,7 +226,7 @@ __deregister_frame_info_bases (void *begin)
 	  {
 	    ob = *p;
 	    *p = ob->next;
-	    free (ob->u.sort);
+	    tofree = ob->u.sort;
 	    goto out;
 	  }
       }
@@ -244,6 +245,7 @@ __deregister_frame_info_bases (void *begin)
 
  out:
   __gthread_mutex_unlock (&object_mutex);
+  free (tofree);
   return (void *) ob;
 }
 hidden_def (__deregister_frame_info_bases)

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                        |    6 ++++++
 sysdeps/generic/unwind-dw2-fde.c |    4 +++-
 2 files changed, 9 insertions(+), 1 deletions(-)


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