percpu: off by one in BUG_ON()

PATCH Applied Dan Carpenter 2 participants 2 messages Oct 29, 2014

Subsystems (3)

Memory management Kernel janitors Per-CPU memory allocator

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Dan Carpenter

author

2014-10-29 08:45 UTC #0 lore raw

PATCH 1/1 percpu: off by one in BUG_ON()

The unit_map[] array has "nr_cpu_ids" number of elements. It's allocated a few lines earlier in the function. So this test should be

Quoted 1 line

= instead of >.

Signed-off-by Dan Carpenter <[email protected]>

---
Static checker stuff. Not tested.

mm/percpu.c +1 -1

index 014bab6..d39e2f4 100644
@@ -1591,7 +1591,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 			if (cpu = NR_CPUS)
 				continue;
 
-			PCPU_SETUP_BUG_ON(cpu > nr_cpu_ids);
+			PCPU_SETUP_BUG_ON(cpu >= nr_cpu_ids);
 			PCPU_SETUP_BUG_ON(!cpu_possible(cpu));
 			PCPU_SETUP_BUG_ON(unit_map[cpu] != UINT_MAX);

Tejun Heo

maintainer Applied

2014-10-29 14:35 UTC #1 lore raw

Quoted 5 lines · Dan Carpenter

The unit_map[] array has "nr_cpu_ids" number of elements. It's allocated a few lines earlier in the function. So this test should be
Quoted 1 line
= instead of >.
Signed-off-by Dan Carpenter <[email protected]>

Applied to percpu/for-3.19.

Thanks.

Signature · 1 line

tejun