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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2014-05-17 20:56:38 +0900 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-10-09 02:39:02 -0400 |
| commit | 475d0db742e3755c6b267f48577ff7cbb7dfda0d (patch) | |
| tree | 68d3bf447201d86cc46ca0b8292d803c2a728b12 | |
| parent | b8314f9303a985354f445763960c0db2d7948891 (diff) | |
| download | linux-475d0db742e3755c6b267f48577ff7cbb7dfda0d.tar.bz2 | |
fs: Fix theoretical division by 0 in super_cache_scan().
total_objects could be 0 and is used as a denom.
While total_objects is a "long", total_objects == 0 unlikely happens for
3.12 and later kernels because 32-bit architectures would not be able to
hold (1 << 32) objects. However, total_objects == 0 may happen for kernels
between 3.1 and 3.11 because total_objects in prune_super() was an "int"
and (e.g.) x86_64 architecture might be able to hold (1 << 32) objects.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable <stable@kernel.org> # 3.1+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/super.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/super.c b/fs/super.c index b9a214d2fe98..6f8c954315c0 100644 --- a/fs/super.c +++ b/fs/super.c @@ -80,6 +80,8 @@ static unsigned long super_cache_scan(struct shrinker *shrink, inodes = list_lru_count_node(&sb->s_inode_lru, sc->nid); dentries = list_lru_count_node(&sb->s_dentry_lru, sc->nid); total_objects = dentries + inodes + fs_objects + 1; + if (!total_objects) + total_objects = 1; /* proportion the scan between the caches */ dentries = mult_frac(sc->nr_to_scan, dentries, total_objects); |