Commit 7cbf3192 authored by Omar Sandoval's avatar Omar Sandoval Committed by Linus Torvalds

mm: fix nr_rotate_swap leak in swapon() error case

If swapon() fails after incrementing nr_rotate_swap, we don't decrement
it and thus effectively leak it.  Make sure we decrement it if we
incremented it.

Link: http://lkml.kernel.org/r/b6fe6b879f17fa68eee6cbd876f459f6e5e33495.1526491581.git.osandov@fb.com
Fixes: 81a0298b ("mm, swap: don't use VMA based swap readahead if HDD is used as swap")
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Reviewed-by: default avatarRik van Riel <riel@surriel.com>
Reviewed-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 62d18ecf
......@@ -3112,6 +3112,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
unsigned long *frontswap_map = NULL;
struct page *page = NULL;
struct inode *inode = NULL;
bool inced_nr_rotate_swap = false;
if (swap_flags & ~SWAP_FLAGS_VALID)
return -EINVAL;
......@@ -3215,8 +3216,10 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
cluster = per_cpu_ptr(p->percpu_cluster, cpu);
cluster_set_null(&cluster->index);
}
} else
} else {
atomic_inc(&nr_rotate_swap);
inced_nr_rotate_swap = true;
}
error = swap_cgroup_swapon(p->type, maxpages);
if (error)
......@@ -3307,6 +3310,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
vfree(swap_map);
kvfree(cluster_info);
kvfree(frontswap_map);
if (inced_nr_rotate_swap)
atomic_dec(&nr_rotate_swap);
if (swap_file) {
if (inode && S_ISREG(inode->i_mode)) {
inode_unlock(inode);
......
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