[GIT PULL] percpu fix for v5.9-rc6

From: Dennis Zhou
Date: Thu Sep 17 2020 - 16:45:19 EST

Hi Linus,

This is a fix for the first chunk size calculation where the variable
length array incorrectly used # of longs instead of bytes of longs. This
came in as a code fix and not a bug report, so I don't think it was
widely problematic. I believe it worked out due to it being memblock
memory and alignment requirements working in our favor.


The following changes since commit f75aef392f869018f78cfedf3c320a6b3fcfda6b:

Linux 5.9-rc3 (2020-08-30 16:01:54 -0700)

are available in the Git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu.git for-5.9-fixes

for you to fetch changes up to b3b33d3c43bbe0177d70653f4e889c78cc37f097:

percpu: fix first chunk size calculation for populated bitmap (2020-09-17 17:34:39 +0000)

Sunghyun Jin (1):
percpu: fix first chunk size calculation for populated bitmap

mm/percpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index f4709629e6de..1ed1a349eab8 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1316,7 +1316,7 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,

/* allocate chunk */
alloc_size = sizeof(struct pcpu_chunk) +
- BITS_TO_LONGS(region_size >> PAGE_SHIFT);
+ BITS_TO_LONGS(region_size >> PAGE_SHIFT) * sizeof(unsigned long);
chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
if (!chunk)
panic("%s: Failed to allocate %zu bytes\n", __func__,