Commit-ID: df54c4934e030e73cb6a7bd6713f697350dabd0b
Gitweb: http://git.kernel.org/tip/df54c4934e030e73cb6a7bd6713f697350dabd0b
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Sun, 2 Aug 2015 20:38:23 +0000
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 6 Aug 2015 00:14:58 +0200
x86/irq: Protect smp_cleanup_move
smp_cleanup_move fiddles without protection in the interrupt
descriptors and the vector array. A concurrent irq setup/teardown or
affinity setting can pull the rug under that operation.
Add proper locking.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20150802203609.222975294@xxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/apic/vector.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index f47069e..63d58b0 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -539,6 +539,9 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void)
entering_ack_irq();
+ /* Prevent vectors vanishing under us */
+ raw_spin_lock(&vector_lock);
+
me = smp_processor_id();
for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; vector++) {
int irq;
@@ -546,6 +549,7 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void)
struct irq_desc *desc;
struct apic_chip_data *data;
+ retry:
irq = __this_cpu_read(vector_irq[vector]);
if (irq <= VECTOR_UNDEFINED)
@@ -555,12 +559,16 @@ asmlinkage __visible void smp_irq_move_cleanup_interrupt(void)
if (!desc)
continue;
+ if (!raw_spin_trylock(&desc->lock)) {
+ raw_spin_unlock(&vector_lock);
+ cpu_relax();
+ raw_spin_lock(&vector_lock);
+ goto retry;
+ }
+
data = apic_chip_data(&desc->irq_data);
if (!data)
- continue;
-
- raw_spin_lock(&desc->lock);
-
+ goto unlock;
/*
* Check if the irq migration is in progress. If so, we
* haven't received the cleanup request yet for this irq.
@@ -589,6 +597,8 @@ unlock:
raw_spin_unlock(&desc->lock);
}
+ raw_spin_unlock(&vector_lock);
+
exiting_irq();
}
--
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