>From 7a2ed4e9c91864736ce5ad89489fd5862d59542e Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Date: Sat, 17 May 2014 20:56:38 +0900 Subject: [PATCH] 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@xxxxxxxxxxxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Cc: stable <stable@xxxxxxxxxx> # 3.1+ --- fs/super.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/fs/super.c b/fs/super.c index 48377f7..1408362 100644 --- a/fs/super.c +++ b/fs/super.c @@ -81,6 +81,8 @@ 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); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
