linux-kernel - [PATCH] shmem: fix double memory uncharge on error path

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Date:	Thu, 12 Sep 2013 17:46:41 +0400
From:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
To:	Hugh Dickins <hughd@...gle.com>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH] shmem: fix double memory uncharge on error path

This patch removes erroneous call of shmem_unacct_size() from error path.
Shmem inode will release that memory reservation in shmem_evict_inode().
So, if following call of alloc_file fails we'll free reservation twice.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@...nvz.org>
---
 mm/shmem.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 8297623..ff08920 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2946,16 +2946,16 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags
 	this.len = strlen(name);
 	this.hash = 0; /* will go */
 	sb = shm_mnt->mnt_sb;
+	path.mnt = mntget(shm_mnt);
 	path.dentry = d_alloc_pseudo(sb, &this);
 	if (!path.dentry)
 		goto put_memory;
 	d_set_d_op(path.dentry, &anon_ops);
-	path.mnt = mntget(shm_mnt);
 
 	res = ERR_PTR(-ENOSPC);
 	inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags);
 	if (!inode)
-		goto put_dentry;
+		goto put_memory;
 
 	d_instantiate(path.dentry, inode);
 	inode->i_size = size;
@@ -2971,10 +2971,10 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags
 
 	return res;
 
-put_dentry:
-	path_put(&path);
 put_memory:
 	shmem_unacct_size(flags, size);
+put_dentry:
+	path_put(&path);
 	return res;
 }
 EXPORT_SYMBOL_GPL(shmem_file_setup);

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