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From:   Miaohe Lin <linmiaohe@huawei.com>
To:     <akpm@linux-foundation.org>, <darrick.wong@oracle.com>
CC:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        <linmiaohe@huawei.com>
Subject: [PATCH] mm: Fix potential memory leak in sys_swapon
Date:   Wed, 30 Sep 2020 06:18:03 -0400
Message-ID: <20200930101803.53884-1-linmiaohe@huawei.com>
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Precedence: bulk

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>
---
 mm/swapfile.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2b0c5fc1b0e6..4522b458a814 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3342,7 +3342,7 @@ 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);
@@ -3367,6 +3367,8 @@ 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:
-- 
2.19.1