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| author | Dennis Zhou <dennis@kernel.org> | 2019-02-22 02:54:11 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-15 12:54:11 +0300 |
| commit | 526972e95ef96cd55313686dbf14202815671f6f (patch) | |
| tree | 29742869e53df3f2592d6634a0e6b072d790b831 | |
| parent | d4d5dce6d32961a0a2f86352a91b643bb2365d6f (diff) | |
| download | linux-526972e95ef96cd55313686dbf14202815671f6f.tar.xz | |
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>
| -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 c66149ce1fe6..ff76fa0b7528 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -988,7 +988,8 @@ 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) |