Attachment 8941 Details for Bug 10035 – FIX: Implement CAIRO_MUTEX_INIT with memcpy instead of pthread_mutex_init

[patch] FIX: Implement CAIRO_MUTEX_INIT with memcpy instead of pthread_mutex_init

0001-Implement-CAIRO_MUTEX_INIT-with-memcpy-instead-of-pthread_mutex_init.txt (text/plain), 1.49 KB, created by Carl Worth on 2007-03-02 00:00:32 UTC

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Creator: Carl Worth

Created: 2007-03-02 00:00:32 UTC

Size: 1.49 KB

patch

obsolete

>From d48bb4fbe876a93199ba48fcf5f32734fbe18ba9 Mon Sep 17 00:00:00 2001
>From: Carl Worth <cworth@cworth.org>
>Date: Thu, 1 Mar 2007 23:34:34 -0800
>Subject: [PATCH] Implement CAIRO_MUTEX_INIT with memcpy instead of pthread_mutex_init
>
>The trick here is that with the weak symbol support for pthreads,
>pthread_mutex_init can be a NOP leaving the mutex uninitialized.
>Then, if some pthread-using library is dynamically loaded, the
>non-NOP pthread functions get used and we end up trying to lock
>an uninitialized mutex.
>
>This should fix the bugs reported here:
>
>	Cairo 1.3.14 deadlocks in cairo_scaled_font_glyph_extents or _cairo_ft_unscaled_font_lock_face
>	https://bugs.freedesktop.org/show_bug.cgi?id=10035
>---
> src/cairoint.h |    5 ++++-
> 1 files changed, 4 insertions(+), 1 deletions(-)
>
>diff --git a/src/cairoint.h b/src/cairoint.h
>index 890929f..3a2d845 100755
>--- a/src/cairoint.h
>+++ b/src/cairoint.h
>@@ -141,7 +141,10 @@ CAIRO_BEGIN_DECLS
> # define CAIRO_MUTEX_LOCK(name) pthread_mutex_lock (&name)
> # define CAIRO_MUTEX_UNLOCK(name) pthread_mutex_unlock (&name)
> typedef pthread_mutex_t cairo_mutex_t;
>-# define CAIRO_MUTEX_INIT(mutex) pthread_mutex_init ((mutex), NULL)
>+#define CAIRO_MUTEX_INIT(mutex) do {				\
>+    pthread_mutex_t tmp_mutex = PTHREAD_MUTEX_INITIALIZER;      \
>+    memcpy (mutex, &tmp_mutex, sizeof (tmp_mutex));             \
>+} while (0)
> # define CAIRO_MUTEX_FINI(mutex) pthread_mutex_destroy (mutex)
> # define CAIRO_MUTEX_NIL_INITIALIZER PTHREAD_MUTEX_INITIALIZER
> #endif
>-- 
>1.5.0.rc1.gf4b6c
>

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