Fixes a regression from
commit 41da295eb5
Author: Keith Packard <keithp@keithp.com>
Date: Sun Nov 3 13:12:40 2013 -0800
Trap SIGBUS to handle truncated shared memory segments
that causes the SIGBUS handler to fail to chain up correctly and
corrupts nearby memory instead.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Fixes a valgrind complaint:
==8805== Syscall param rt_sigaction(act->sa_mask) points to uninitialised byte(s)
==8805== at 0x5EB8315: __libc_sigaction (sigaction.c:66)
==8805== by 0x5B13DA: busfault_init (busfault.c:145)
==8805== by 0x5A60A2: OsInit (osinit.c:191)
==8805== by 0x46EBA2: dix_main (main.c:163)
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
The former doesn't exist on BSD and the latter is available everywhere
AFAIK (checked Solaris and Linux).
You also might want to wrap that line ;).
Reported-by: Mark Kettenis <mark.kettenis@xs4all.nl>
Signed-off-by: Keith Packard <keithp@keithp.com>
If a client passes a section of memory via file descriptor and then
subsequently truncates that file, the underlying pages will be freed
and the addresses invalidated. Subsequent accesses to the page will
fail with a SIGBUS error.
Trap that SIGBUS, figure out which segment was causing the error and
then allocate new pages to fill in for that region. Mark the offending
shared segment as invalid and free the resource ID so that the client
will be able to tell when subsequently attempting to use the segment.
Signed-off-by: Keith Packard <keithp@keithp.com>
v2: Use MAP_FIXED to simplify the recovery logic (Mark Kettenis)
v3: Also catch errors in ShmCreateSegment
Conflicts:
include/dix-config.h.in
include/xorg-config.h.in
