The patch titled
Subject: mm: fix nr_rotate_swap leak in swapon() error case
has been added to the -mm tree. Its filename is
mm-fix-nr_rotate_swap-leak-in-swapon-error-case.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-nr_rotate_swap-leak-in-swapon-error-case.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-nr_rotate_swap-leak-in-swapon-error-case.patch
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------------------------------------------------------
From: Omar Sandoval <osandov@xxxxxx>
Subject: 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@xxxxxx
Fixes: 81a0298bdfab ("mm, swap: don't use VMA based swap readahead if HDD is used as swap")
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxxx>
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff -puN mm/swapfile.c~mm-fix-nr_rotate_swap-leak-in-swapon-error-case mm/swapfile.c
--- a/mm/swapfile.c~mm-fix-nr_rotate_swap-leak-in-swapon-error-case
+++ a/mm/swapfile.c
@@ -3112,6 +3112,7 @@ SYSCALL_DEFINE2(swapon, const char __use
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 __use
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 @@ bad_swap:
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);
_
Patches currently in -mm which might be from osandov@xxxxxx are
mm-fix-nr_rotate_swap-leak-in-swapon-error-case.patch
lockdep-fix-fs_reclaim-annotation.patch
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