Bug 41048

Summary:	can crash on failed realloc; cannot be forced to crash on all failed mallocs
Product:	dbus	Reporter:	Simon McVittie <smcv>
Component:	core	Assignee:	Simon McVittie <smcv>
Status:	RESOLVED FIXED	QA Contact:	John (J5) Palmieri <johnp>
Severity:	enhancement
Priority:	medium	CC:	hp
Version:	1.4.x	Keywords:	patch
Hardware:	Other
OS:	All
URL:	http://cgit.freedesktop.org/~smcv/dbus/log/?h=14-malloc-cannot-fail-41048
Whiteboard:
i915 platform:		i915 features:
Attachments:	[1/2] dbus_realloc: don't crash if realloc() returns NULL while using guards [2/2] dbus-memory: add optional checking for system malloc() (etc.) failing

Description Simon McVittie 2011-09-20 11:03:27 UTC

libdbus tries to behave in a way suitable for a core system service, for instance by surviving (and rolling back a transaction) if memory allocators return NULL.

A bug and an enhancement in this direction:

* One call to realloc() is not checked, so libdbus crashes if it returns NULL.
  My first patch checks it.

* To debug memory issues, it would be useful to be able to put libdbus in
  a GLib-like mode where malloc failures are fatal, particularly when combined
  with a small rlimit. My second patch adds this; for the moment it depends
  on DBUS_BUILD_TESTS.

Comment 1 Simon McVittie 2011-09-20 11:04:26 UTC

Created attachment 51416 [details] [review]
[1/2] dbus_realloc: don't crash if realloc() returns NULL while using guards

Comment 2 Simon McVittie 2011-09-20 11:04:48 UTC

Created attachment 51417 [details] [review]
[2/2] dbus-memory: add optional checking for system malloc() (etc.) failing

If tests are enabled and DBUS_MALLOC_CANNOT_FAIL is set, abort on system
malloc() failures (as GLib's g_malloc does). This can be used in
conjunction with a resource limit, to turn runaway memory leaks into a
debuggable core-dump.

Comment 3 Guillaume Desmottes 2012-02-20 05:22:51 UTC

Comment on attachment 51416 [details] [review]
[1/2] dbus_realloc: don't crash if realloc() returns NULL while using guards

Review of attachment 51416 [details] [review]:
-----------------------------------------------------------------

++

Comment 4 Guillaume Desmottes 2012-02-20 05:50:07 UTC

Comment on attachment 51417 [details] [review]
[2/2] dbus-memory: add optional checking for system malloc() (etc.) failing

Review of attachment 51417 [details] [review]:
-----------------------------------------------------------------

++

Comment 5 Simon McVittie 2012-02-21 07:15:10 UTC

Fixed in git for 1.5.10, thanks. I didn't merge this for 1.4 in the end.

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