Subject: + modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount.patch added to -mm tree
To: cl@xxxxxxxxx,mingo@xxxxxxxxxx,rusty@xxxxxxxxxxxxxxx,tj@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 04 Mar 2014 14:27:06 -0800
The patch titled
Subject: modules: use raw_cpu_write for initialization of per cpu refcount.
has been added to the -mm tree. Its filename is
modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount.patch
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From: Christoph Lameter <cl@xxxxxxxxx>
Subject: modules: use raw_cpu_write for initialization of per cpu refcount.
The initialization of a structure is not subject to synchronization. The
use of __this_cpu would trigger a false positive with the additional
preemption checks for __this_cpu ops.
So simply disable the check through the use of raw_cpu ops.
Trace:
[ 0.668066] __this_cpu_write operation in preemptible [00000000] code: modprobe/286
[ 0.668108] caller is __this_cpu_preempt_check+0x38/0x60
[ 0.668111] CPU: 3 PID: 286 Comm: modprobe Tainted: GF 3.12.0-rc4+ #187
[ 0.668112] Hardware name: FUJITSU CELSIUS W530 Power/D3227-A1, BIOS V4.6.5.4 R1.10.0 for D3227-A1x 09/16/2013
[ 0.668113] 0000000000000003 ffff8807edda1d18 ffffffff816d5a57 ffff8807edda1fd8
[ 0.668117] ffff8807edda1d48 ffffffff8137359c ffff8807edda1ef8 ffffffffa0002178
[ 0.668121] ffffc90000067730 ffff8807edda1e48 ffff8807edda1d88 ffffffff813735f8
[ 0.668124] Call Trace:
[ 0.668129] [<ffffffff816d5a57>] dump_stack+0x4e/0x82
[ 0.668132] [<ffffffff8137359c>] check_preemption_disabled+0xec/0x110
[ 0.668135] [<ffffffff813735f8>] __this_cpu_preempt_check+0x38/0x60
[ 0.668139] [<ffffffff810c24fd>] load_module+0xcfd/0x2650
[ 0.668143] [<ffffffff816dd922>] ? page_fault+0x22/0x30
[ 0.668146] [<ffffffff810c3ef6>] SyS_init_module+0xa6/0xd0
[ 0.668150] [<ffffffff816e4fd3>] tracesys+0xe1/0xe6
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/module.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/module.c~modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount kernel/module.c
--- a/kernel/module.c~modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount
+++ a/kernel/module.c
@@ -640,7 +640,7 @@ static int module_unload_init(struct mod
INIT_LIST_HEAD(&mod->target_list);
/* Hold reference count during initialization. */
- __this_cpu_write(mod->refptr->incs, 1);
+ raw_cpu_write(mod->refptr->incs, 1);
return 0;
}
_
Patches currently in -mm which might be from cl@xxxxxxxxx are
mm-close-pagetail-race.patch
mm-page_alloc-make-first_page-visible-before-pagetail.patch
kthread-ensure-locality-of-task_struct-allocations.patch
mm-slab-slub-use-page-list-consistently-instead-of-page-lru.patch
kobject-dont-block-for-each-kobject_uevent.patch
kobject-dont-block-for-each-kobject_uevent-v2.patch
slub-do-not-drop-slab_mutex-for-sysfs_slab_add.patch
kmod-run-usermodehelpers-only-on-cpus-allowed-for-kthreadd-v2.patch
kmod-run-usermodehelpers-only-on-cpus-allowed-for-kthreadd-v2-fix.patch
kmod-run-usermodehelpers-only-on-cpus-allowed-for-kthreadd-v2-checkpatch-fixes.patch
linux-next.patch
percpu-add-raw_cpu_ops.patch
mm-use-raw_cpu-ops-for-determining-current-numa-node.patch
modules-use-raw_cpu_write-for-initialization-of-per-cpu-refcount.patch
net-replace-__this_cpu_inc-in-routec-with-raw_cpu_inc.patch
percpu-add-preemption-checks-to-__this_cpu-ops.patch
mm-replace-__get_cpu_var-uses-with-this_cpu_ptr.patch
tracing-replace-__get_cpu_var-uses-with-this_cpu_ptr.patch
percpu-replace-__get_cpu_var-with-this_cpu_ptr.patch
kernel-misc-replace-__get_cpu_var-uses.patch
drivers-char-random-replace-__get_cpu_var-uses.patch
drivers-cpuidle-replace-__get_cpu_var-uses-for-address-calculation.patch
drivers-oprofile-replace-__get_cpu_var-uses-for-address-calculation.patch
drivers-leds-replace-__get_cpu_var-use-through-this_cpu_ptr.patch
drivers-clocksource-replace-__get_cpu_var-used-for-address-calculation.patch
parisc-replace-__get_cpu_var-uses-for-address-calculation.patch
metag-replace-__get_cpu_var-uses-for-address-calculation.patch
drivers-net-ethernet-tile-replace-__get_cpu_var-uses-for-address-calculation.patch
drivers-net-ethernet-tile-__get_cpu_var-call-introduced-in-314.patch
tilegx-another-case-of-get_cpu_var.patch
time-replace-__get_cpu_var-uses.patch
scheduler-replace-__get_cpu_var-with-this_cpu_ptr.patch
tick-sched-fix-two-new-uses-of-__get_cpu_ptr.patch
block-replace-__this_cpu_ptr-with-raw_cpu_ptr.patch
rcu-replace-__this_cpu_ptr-uses-with-raw_cpu_ptr.patch
watchdog-replace-__raw_get_cpu_var-uses.patch
net-replace-get_cpu_var-through-this_cpu_ptr.patch
md-replace-__this_cpu_ptr-with-raw_cpu_ptr.patch
irqchips-replace-__this_cpu_ptr-uses.patch
x86-replace-__get_cpu_var-uses.patch
x86-change-__get_cpu_var-calls-introduced-in-314.patch
uv-replace-__get_cpu_var.patch
arm-replace-__this_cpu_ptr-with-raw_cpu_ptr.patch
mips-replace-__get_cpu_var-uses-in-fpu-emulator.patch
mips-replace-__get_cpu_var-uses.patch
s390-rename-__this_cpu_ptr-to-raw_cpu_ptr.patch
s390-replace-__get_cpu_var-uses.patch
s390-handle-new-__get_cpu_var-calls-added-in-314.patch
ia64-replace-__get_cpu_var-uses.patch
powerpc-replace-__get_cpu_var-uses.patch
powerpc-handle-new-__get_cpu_var-calls-in-314.patch
sparc-replace-__get_cpu_var-uses.patch
tile-replace-__get_cpu_var-uses.patch
blackfin-replace-__get_cpu_var-uses.patch
avr32-replace-__get_cpu_var-with-__this_cpu_write.patch
alpha-replace-__get_cpu_var.patch
sh-replace-__get_cpu_var-uses.patch
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