From 822bca52ee7eb279acfba261a423ed7ac47d6f73 Mon Sep 17 00:00:00 2001
From: Miaohe Lin <linmiaohe@huawei.com>
Date: Tue Oct 13 16:52:30 2020 -0700
Subject: [PATCH] mm/swapfile.c: fix potential memory leak in sys_swapon 
Git-commit: 822bca52ee7eb279acfba261a423ed7ac47d6f73
References: git-fixes
Patch-mainline: v5.10-rc1

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>
Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index b23090c..c4a6136 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: