diff options
| author | Andreas Larsson <andreas@gaisler.com> | 2014-12-18 13:23:23 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-03-26 15:00:54 +0100 |
| commit | 243bd1fa3b9911d6722304a2748ffe10487e3988 (patch) | |
| tree | 85c5238d4dfe8f0b0282f25b3869ebcc2a683e11 /arch | |
| parent | 7f4e64246049cef5ae1eca37eec1701a9477799e (diff) | |
sparc32: destroy_context() and switch_mm() needs to disable interrupts.
[ Upstream commit 66d0f7ec9f1038452178b1993fc07fd96d30fd38 ]
Load balancing can be triggered in the critical sections protected by
srmmu_context_spinlock in destroy_context() and switch_mm() and can hang
the cpu waiting for the rq lock of another cpu that in turn has called
switch_mm hangning on srmmu_context_spinlock leading to deadlock.
So, disable interrupt while taking srmmu_context_spinlock in
destroy_context() and switch_mm() so we don't deadlock.
See also commit 77b838fa1ef0 ("[SPARC64]: destroy_context() needs to disable
interrupts.")
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/sparc/mm/srmmu.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c index 036c2797dece..f58cb540ff94 100644 --- a/arch/sparc/mm/srmmu.c +++ b/arch/sparc/mm/srmmu.c @@ -455,10 +455,12 @@ static void __init sparc_context_init(int numctx) void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk) { + unsigned long flags; + if (mm->context == NO_CONTEXT) { - spin_lock(&srmmu_context_spinlock); + spin_lock_irqsave(&srmmu_context_spinlock, flags); alloc_context(old_mm, mm); - spin_unlock(&srmmu_context_spinlock); + spin_unlock_irqrestore(&srmmu_context_spinlock, flags); srmmu_ctxd_set(&srmmu_context_table[mm->context], mm->pgd); } @@ -983,14 +985,15 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm) void destroy_context(struct mm_struct *mm) { + unsigned long flags; if (mm->context != NO_CONTEXT) { flush_cache_mm(mm); srmmu_ctxd_set(&srmmu_context_table[mm->context], srmmu_swapper_pg_dir); flush_tlb_mm(mm); - spin_lock(&srmmu_context_spinlock); + spin_lock_irqsave(&srmmu_context_spinlock, flags); free_context(mm->context); - spin_unlock(&srmmu_context_spinlock); + spin_unlock_irqrestore(&srmmu_context_spinlock, flags); mm->context = NO_CONTEXT; } } |