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d150a2b965
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Mathieu Desnoyers d150a2b965 module: fix __module_ref_addr() 
The __module_ref_addr() problem disappears in 2.6.34-rc kernels because these
percpu accesses were re-factored.

__module_ref_addr() should use per_cpu_ptr() to obfuscate the pointer
(RELOC_HIDE is needed for per cpu pointers).

This non-standard per-cpu pointer use has been introduced by commit
720eba31f4

It causes a NULL pointer exception on some configurations when CONFIG_TRACING is
enabled on 2.6.33. This patch fixes the problem (acknowledged by Randy who
reported the bug).

It did not appear to hurt previously because most of the accesses were done
through local_inc, which probably obfuscated the access enough that no compiler
optimizations were done. But with local_read() done when CONFIG_TRACING is
active, this becomes a problem. Non-CONFIG_TRACING is probably affected as well
(module.c contains local_set and local_read that use __module_ref_addr()), but I
guess nobody noticed because we've been lucky enough that the compiler did not
generate the inappropriate optimization pattern there.

This patch should be queued for the 2.6.29.x through 2.6.33.x stable branches.
(tested on 2.6.33.1 x86_64)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Tested-by: Randy Dunlap <randy.dunlap@oracle.com>
CC: Eric Dumazet <dada1@cosmosbay.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Tejun Heo <tj@kernel.org>
CC: Ingo Molnar <mingo@elte.hu>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-04-26 07:41:35 -07:00
..
acpi ACPI: don't cond_resched if irq is disabled 2010-01-28 15:00:26 -08:00
asm-generic fcntl: rename F_OWNER_GID to F_OWNER_PGRP 2009-11-17 17:40:33 -08:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2009-09-11 09:38:37 -07:00
drm drm/radeon/kms: add FireMV 2400 PCI ID. 2010-04-26 07:41:26 -07:00
keys RxRPC: Use uX/sX rather than uintX_t/intX_t types 2009-09-16 00:01:13 -07:00
linux module: fix __module_ref_addr() 2010-04-26 07:41:35 -07:00
math-emu
media V4L/DVB (13019): video: initial support for ADV7180 2009-09-19 00:53:39 -03:00
mtd Kill jffs2-user.h 2009-06-05 17:31:38 +01:00
net mac80211: Retry null data frame for power save 2010-04-01 15:58:52 -07:00
pcmcia PM / yenta: Split resume into early and late parts (rev. 4) 2009-11-03 10:54:58 +01:00
rdma trivial: fix typo "to to" in multiple files 2009-09-21 15:14:55 +02:00
rxrpc
scsi SCSI: fc-transport: Use packed modifier for fc_bsg_request structure. 2010-04-26 07:41:30 -07:00
sound Merge branch 'topic/ymfpci' into for-linus 2009-09-10 15:33:09 +02:00
trace tracing: Fix event format export 2009-12-18 14:05:16 -08:00
video davinci-fb-frame-buffer-driver-for-ti-da8xx-omap-l1xx-v4 2009-09-23 07:39:51 -07:00
xen
Kbuild [SCSI] FC Pass Thru support 2009-06-12 14:20:05 -05:00