From 2604882cefd3281679b8177245fdebc7061b8695 Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Mon, 17 Apr 2017 12:03:44 -0300 Subject: [PATCH] [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. --- ChangeLog | 6 ++++++ sysdeps/generic/unwind-dw2-fde.c | 4 +++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index b209f9c..bfda0e1 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2017-04-17 Rabin Vincent + + [BZ #21357] + * sysdeps/generic/unwind-dw2-fde.c (__deregister_frame_info_bases): + Call free() outside of mutex. + 2017-04-13 Florian Weimer * 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) -- 2.7.4