[PATCH 5.8 316/633] mm/swapfile.c: fix potential memory leak in sys_swapon

Greg Kroah-Hartman
2020-10-27T15:09:58Z

From: Miaohe Lin <linmiaohe@huawei.com>

[ Upstream commit 822bca52ee7eb279acfba261a423ed7ac47d6f73 ]

If we failed to drain inode, we would forget to free the swap address
space allocated by init_swap_address_space() above.

Fixes: dc617f29dbe5 ("vfs: don't allow writes to swap files")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lkml.kernel.org/r/20200930101803.53884-1-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
mm/swapfile.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 26707c5dc9fce..605294e4df684 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3336,7 +3336,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
error = inode_drain_writes(inode);
if (error) {
inode->i_flags &= ~S_SWAPFILE;
- goto bad_swap_unlock_inode;
+ goto free_swap_address_space;
}

mutex_lock(&swapon_mutex);
@@ -3361,6 +3361,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)

error = 0;
goto out;
+free_swap_address_space:
+ exit_swap_address_space(p->type);
bad_swap_unlock_inode:
inode_unlock(inode);
bad_swap:
--
2.25.1