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

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>

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index 96c0c86f3fffe59bc2b7b324e9b94fcc89ca5192..0297ad95eb5cc01cafe158185e890b3ed214b40e 100644 (file)
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -7,6 +7,7 @@
 #include <linux/efi.h>
 #include <linux/fs.h>
 #include <linux/ctype.h>
+#include <linux/kmemleak.h>
 #include <linux/slab.h>
 #include <linux/uuid.h>
 
@@ -103,6 +104,7 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
        var->var.VariableName[i] = '\0';
 
        inode->i_private = var;
+       kmemleak_ignore(var);
 
        err = efivar_entry_add(var, &efivarfs_list);
        if (err)

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index f943fd0b0699c2faf99bb249d2b30807916cf4c4..15880a68faadc58ba34d1a3f68ac412416202f2e 100644 (file)
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -21,7 +21,6 @@ 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 = {