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authorMatthew Wilcox (Oracle) <willy@infradead.org>2024-04-29 15:47:51 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2024-04-29 08:29:29 -0700
commit5af385f5f4cddf908f663974847a4083b2ff2c79 (patch)
treee24621c9def52fb32b1ad599376e8a10c95ea163
parente67572cd2204894179d89bd7b984072f19313b03 (diff)
bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS
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@rosalinux.ru> Tested-by: Ильфат Гаптрахманов <i.gaptrakhmanov@rosalinux.ru> Link: https://gitlab.freedesktop.org/drm/amd/-/issues/3347 Link: https://lore.kernel.org/all/1c978cf1-2934-4e66-e4b3-e81b04cb3571@rosalinux.ru/ Fixes: f2d5dcb48f7b (bounds: support non-power-of-two CONFIG_NR_CPUS) Cc: <stable@vger.kernel.org> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/bounds.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bounds.c b/kernel/bounds.c
index c5a9fcd2d622..29b2cd00df2c 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, order_base_2(CONFIG_NR_CPUS));
#endif
DEFINE(SPINLOCK_SIZE, sizeof(spinlock_t));
#ifdef CONFIG_LRU_GEN