diff options
| author | Michael Catanzaro <mcatanzaro@gnome.org> | 2020-11-23 15:51:16 -0600 |
|---|---|---|
| committer | Michael Catanzaro <mcatanzaro@gnome.org> | 2020-11-24 08:10:58 -0600 |
| commit | a412ffe4d3b3775c00703cf31dd302b1200fd0e5 (patch) | |
| tree | 261ec1d725d81db07e4282b0aed215f6dbde48a4 | |
| parent | 23ad18791dc2138bc6f5b98465c9e8e898cbdbbe (diff) | |
gatomicarray: suppress valgrind memory leak warnings
The problem occurs because we keep a pointer inside the allocated block,
instead of a pointer to the start of the block:
```
==180238== 16 bytes in 1 blocks are possibly lost in loss record 3,086 of 16,075
==180238== at 0x483980B: malloc (vg_replace_malloc.c:309)
==180238== by 0x548942C: g_malloc (gmem.c:102)
==180238== by 0x54A4748: g_slice_alloc (gslice.c:1025)
==180238== by 0x53D0AAF: freelist_alloc (gatomicarray.c:77)
==180238== by 0x53D0B85: _g_atomic_array_copy (gatomicarray.c:133)
==180238== by 0x53F8E6D: iface_node_set_offset_L (gtype.c:1347)
==180238== by 0x53F91F1: type_node_add_iface_entry_W (gtype.c:1444)
==180238== by 0x53F93DF: type_add_interface_Wm (gtype.c:1477)
==180238== by 0x53FC946: g_type_add_interface_static (gtype.c:2852)
==180238== by 0x4A3D53A: gtk_menu_shell_accessible_get_type_once (gtkmenushellaccessible.c:26)
==180238== by 0x4A3D495: gtk_menu_shell_accessible_get_type (gtkmenushellaccessible.c:26)
==180238== by 0x4C8AC44: gtk_menu_shell_class_init (gtkmenushell.c:424)
```
Note we cannot use VALGRIND_FREELIKE_BLOCK() in freelist_free() because we
have not actually freed the FreeListNode and need to dereference it in
freelist_alloc() to decide whether to reuse the block. That would result
in a use-after-free warning before we would get a chance to call
VALGRIND_MALLOCLIKE_BLOCK() in the reuse path.
Also note that this free list only ever grows: it never shrinks for the
lifetime of the application, so nothing here will ever be truely freed,
although unused elements are eligible for reuse.
Fix suggested by Philip Withnall
Related: #2076
| -rw-r--r-- | gobject/gatomicarray.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/gobject/gatomicarray.c b/gobject/gatomicarray.c index 5ebf6b89b..43111e8c7 100644 --- a/gobject/gatomicarray.c +++ b/gobject/gatomicarray.c @@ -17,6 +17,7 @@ #include "config.h" +#include "../glib/gvalgrind.h" #include <string.h> #include "gatomicarray.h" @@ -77,6 +78,11 @@ freelist_alloc (gsize size, gboolean reuse) mem = g_slice_alloc (real_size); mem = ((char *) mem) + sizeof (gsize); G_ATOMIC_ARRAY_DATA_SIZE (mem) = size; + +#if ENABLE_VALGRIND + VALGRIND_MALLOCLIKE_BLOCK (mem, real_size - sizeof (gsize), FALSE, FALSE); +#endif + return mem; } |