efivarfs: revert "fix memory leak in efivarfs_create()"

[ Upstream commit ff04f3b6f2e27f8ae28a498416af2a8dd5072b43 ]

The memory leak addressed by commit fe5186cf12e3 is a false positive:
all allocations are recorded in a linked list, and freed when the
filesystem is unmounted. This leads to double frees, and as reported
by David, leads to crashes if SLUB is configured to self destruct when
double frees occur.

So drop the redundant kfree() again, and instead, mark the offending
pointer variable so the allocation is ignored by kmemleak.

Cc: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
Fixes: fe5186cf12e3 ("efivarfs: fix memory leak in efivarfs_create()")
Reported-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index e2ab6d0497f2bb86dee165421487d27e4b64ba0d..151884b95ee2fb3980489e061306c9ec912ba7fb 100644 (file)
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -10,6 +10,7 @@
 #include <linux/efi.h>
 #include <linux/fs.h>
 #include <linux/ctype.h>
+#include <linux/kmemleak.h>
 #include <linux/slab.h>
 
 #include "internal.h"
@@ -138,6 +139,7 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
        var->var.VariableName[i] = '\0';
 
        inode->i_private = var;
+       kmemleak_ignore(var);
 
        efivar_entry_add(var, &efivarfs_list);
        d_instantiate(dentry, inode);

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 0e4f20377d196407c51d7c9d192320c3c2b6e8bf..fca235020312d5641178630f923d481fc2725397 100644 (file)
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -23,7 +23,6 @@ LIST_HEAD(efivarfs_list);
 static void efivarfs_evict_inode(struct inode *inode)
 {
        clear_inode(inode);
-       kfree(inode->i_private);
 }
 
 static const struct super_operations efivarfs_ops = {