linux/include
Jeff Mahoney 4be2c95d1f taskstats: pad taskstats netlink response for aligment issues on ia64
The taskstats structure is internally aligned on 8 byte boundaries but the
layout of the aggregrate reply, with two NLA headers and the pid (each 4
bytes), actually force the entire structure to be unaligned.  This causes
the kernel to issue unaligned access warnings on some architectures like
ia64.  Unfortunately, some software out there doesn't properly unroll the
NLA packet and assumes that the start of the taskstats structure will
always be 20 bytes from the start of the netlink payload.  Aligning the
start of the taskstats structure breaks this software, which we don't
want.  So, for now the alignment only happens on architectures that
require it and those users will have to update to fixed versions of those
packages.  Space is reserved in the packet only when needed.  This ifdef
should be removed in several years e.g.  2012 once we can be confident
that fixed versions are installed on most systems.  We add the padding
before the aggregate since the aggregate is already a defined type.

Commit 85893120 ("delayacct: align to 8 byte boundary on 64-bit systems")
previously addressed the alignment issues by padding out the pid field.
This was supposed to be a compatible change but the circumstances
described above mean that it wasn't.  This patch backs out that change,
since it was a hack, and introduces a new NULL attribute type to provide
the padding.  Padding the response with 4 bytes avoids allocating an
aligned taskstats structure and copying it back.  Since the structure
weighs in at 328 bytes, it's too big to do it on the stack.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reported-by: Brian Rogers <brian@xyzw.org>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Guillaume Chazarain <guichaz@gmail.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-22 19:43:34 -08:00
..
acpi ACPI: video: fix build for CONFIG_ACPI=n 2010-12-11 02:01:46 -05:00
asm-generic asm-generic/stat.h: support 64-bit file time_t for stat() 2010-11-01 15:31:29 -04:00
crypto Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2010-10-24 13:41:39 -07:00
drm drm/i915: announce to userspace that the bsd ring is coherent 2010-12-05 10:40:39 +00:00
keys
linux taskstats: pad taskstats netlink response for aligment issues on ia64 2010-12-22 19:43:34 -08:00
math-emu
media Merge branch 'v4l_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6 2010-12-20 10:35:04 -08:00
mtd mtd: Define MLC Flash as a different flash type 2010-10-25 00:50:20 +01:00
net filter: fix sk_filter rcu handling 2010-12-06 09:29:43 -08:00
pcmcia pcmcia: IOCARD is also required for using IRQs 2010-10-22 08:46:36 +02:00
rdma IB/core: Add VLAN support for IBoE 2010-10-25 10:20:39 -07:00
rxrpc
scsi SCSI host lock push-down 2010-11-16 13:33:23 -08:00
sound ARM: mach-shmobile: ap4evb: FSI clock use proper process for HDMI 2010-11-24 15:29:56 +09:00
trace ext4: Add new ext4 inode tracepoints 2010-11-08 13:51:33 -05:00
video fbdev: da8xx: punt duplicated FBIO_WAITFORVSYNC define 2010-11-16 10:14:22 +09:00
xen xen: Provide a variant of __RING_SIZE() that is an integer constant expression 2010-12-15 12:34:28 -08:00
Kbuild