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percpu: initialize best_upa variable 

Tom reported this finding from clang 10's static analysis [1].

Due to the way the code is written, it will always see a successful loop
iteration. Instead of setting an initial value, check that it was set
instead with BUG_ON() because 0 units per allocation is bogus.

[1] https://lore.kernel.org/lkml/20210515180817.1751084-1-trix@redhat.com/

Reported-by: Tom Rix <trix@redhat.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
This commit is contained in:
Dennis Zhou 2021-06-14 14:42:05 +00:00
parent faf65dde84
commit 4829c791b2
1 changed files with 2 additions and 0 deletions
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2
mm/percpu.c
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@ -2888,6 +2888,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
* Related to atom_size, which could be much larger than the unit_size.
*/
last_allocs = INT_MAX;
best_upa = 0;
for (upa = max_upa; upa; upa--) {
int allocs = 0, wasted = 0;
@ -2914,6 +2915,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
last_allocs = allocs;
best_upa = upa;
}
BUG_ON(!best_upa);
upa = best_upa;
/* allocate and fill alloc_info */