bits_per() rounds up to the next power of two when passed a power of two. This causes crashes on some machines and configurations. Reported-by: Михаил Новоселов <m.novosyolov@xxxxxxxxxxxx> Tested-by: Ильфат Гаптрахманов <i.gaptrakhmanov@xxxxxxxxxxxx> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3347 Link: https://lore.kernel.org/all/1c978cf1-2934-4e66-e4b3-e81b04cb3571@xxxxxxxxxxxx/ Fixes: f2d5dcb48f7b (bounds: support non-power-of-two CONFIG_NR_CPUS) Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/bounds.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bounds.c b/kernel/bounds.c index c5a9fcd2d622..8553368ccf79 100644 --- a/kernel/bounds.c +++ b/kernel/bounds.c @@ -19,7 +19,7 @@ int main(void) DEFINE(NR_PAGEFLAGS, __NR_PAGEFLAGS); DEFINE(MAX_NR_ZONES, __MAX_NR_ZONES); #ifdef CONFIG_SMP - DEFINE(NR_CPUS_BITS, bits_per(CONFIG_NR_CPUS)); + DEFINE(NR_CPUS_BITS, bits_per(CONFIG_NR_CPUS - 1)); #endif DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t)); #ifdef CONFIG_LRU_GEN -- 2.43.0
