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authorDimitri Sivanich <sivanich@sgi.com>2010-12-28 13:34:42 -0600
committerTony Luck <tony.luck@intel.com>2010-12-28 14:06:21 -0800
commit75c1c91cb92806f960fcd6e53d2a0c21f343081c (patch)
treef87fd2f7cf75b9d2b1180452120f8dd852d2c9b6 /arch/ia64
parent90a8a73c06cc32b609a880d48449d7083327e11a (diff)
downloadlinux-2.6.38-lt-ux500-75c1c91cb92806f960fcd6e53d2a0c21f343081c.tar.gz
[IA64] eliminate race condition in smp_flush_tlb_mm
A race condition exists within smp_call_function_many() when called from smp_flush_tlb_mm(). On rare occasions the cpu_vm_mask can be cleared while smp_call_function_many is executing, occasionally resulting in a hung process. Make a copy of the mask prior to calling smp_call_function_many(). Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/kernel/smp.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/ia64/kernel/smp.c b/arch/ia64/kernel/smp.c
index dabeefe2113..be450a3e987 100644
--- a/arch/ia64/kernel/smp.c
+++ b/arch/ia64/kernel/smp.c
@@ -293,6 +293,7 @@ smp_flush_tlb_all (void)
void
smp_flush_tlb_mm (struct mm_struct *mm)
{
+ cpumask_var_t cpus;
preempt_disable();
/* this happens for the common case of a single-threaded fork(): */
if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
@@ -301,9 +302,15 @@ smp_flush_tlb_mm (struct mm_struct *mm)
preempt_enable();
return;
}
-
- smp_call_function_many(mm_cpumask(mm),
- (void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
+ if (!alloc_cpumask_var(&cpus, GFP_ATOMIC)) {
+ smp_call_function((void (*)(void *))local_finish_flush_tlb_mm,
+ mm, 1);
+ } else {
+ cpumask_copy(cpus, mm_cpumask(mm));
+ smp_call_function_many(cpus,
+ (void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
+ free_cpumask_var(cpus);
+ }
local_irq_disable();
local_finish_flush_tlb_mm(mm);
local_irq_enable();