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| author | Thomas Gleixner <tglx@linutronix.de> | 2020-08-30 20:07:53 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-08-30 20:17:28 +0300 |
| commit | 784a0830377d0761834e385975bc46861fea9fa0 (patch) | |
| tree | de2129665415c58942d30408b6f5af2028821b57 /kernel | |
| parent | e027fffff799cdd70400c5485b1a54f482255985 (diff) | |
| download | linux-784a0830377d0761834e385975bc46861fea9fa0.tar.xz | |
genirq/matrix: Deal with the sillyness of for_each_cpu() on UP
Most of the CPU mask operations behave the same way, but for_each_cpu() and
it's variants ignore the cpumask argument and claim that CPU0 is always in
the mask. This is historical, inconsistent and annoying behaviour.
The matrix allocator uses for_each_cpu() and can be called on UP with an
empty cpumask. The calling code does not expect that this succeeds but
until commit e027fffff799 ("x86/irq: Unbreak interrupt affinity setting")
this went unnoticed. That commit added a WARN_ON() to catch cases which
move an interrupt from one vector to another on the same CPU. The warning
triggers on UP.
Add a check for the cpumask being empty to prevent this.
Fixes: 2f75d9e1c905 ("genirq: Implement bitmap matrix allocator")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq/matrix.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c index 30cc217b8631..651a4ad6d711 100644 --- a/kernel/irq/matrix.c +++ b/kernel/irq/matrix.c @@ -380,6 +380,13 @@ int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk, unsigned int cpu, bit; struct cpumap *cm; + /* + * Not required in theory, but matrix_find_best_cpu() uses + * for_each_cpu() which ignores the cpumask on UP . + */ + if (cpumask_empty(msk)) + return -EINVAL; + cpu = matrix_find_best_cpu(m, msk); if (cpu == UINT_MAX) return -ENOSPC; |