diff options
| author | Dennis Zhou <dennis@kernel.org> | 2019-02-21 15:54:11 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-15 11:54:59 +0200 |
| commit | 4794604a68922b179c334a7a2e6942ffa2e6b893 (patch) | |
| tree | 335f1c51844db49480d5bcd7f7ddb9f0596d396f /mm | |
| parent | 3e729a2c5a465fb3f295137020570269d96ee0d2 (diff) | |
percpu: do not search past bitmap when allocating an area
[ Upstream commit 8c43004af01635cc9fbb11031d070e5e0d327ef2 ]
pcpu_find_block_fit() guarantees that a fit is found within
PCPU_BITMAP_BLOCK_BITS. Iteration is used to determine the first fit as
it compares against the block's contig_hint. This can lead to
incorrectly scanning past the end of the bitmap. The behavior was okay
given the check after for bit_off >= end and the correctness of the
hints from pcpu_find_block_fit().
This patch fixes this by bounding the end offset by the number of bits
in a chunk.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/percpu.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index bc58bcbe4b60..9beb84800d8d 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -984,7 +984,8 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, /* * Search to find a fit. */ - end = start + alloc_bits + PCPU_BITMAP_BLOCK_BITS; + end = min_t(int, start + alloc_bits + PCPU_BITMAP_BLOCK_BITS, + pcpu_chunk_map_bits(chunk)); bit_off = bitmap_find_next_zero_area(chunk->alloc_map, end, start, alloc_bits, align_mask); if (bit_off >= end) |