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 71fccccf317e8849580457680d6bd6ac3376c170..5decb3e06563f5fd8af57f8f2bda7fc98321256e 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 <linux/uuid.h>
 
@@ -104,6 +105,7 @@ 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 7808a26bd33fa4aa351cb23e77ed5bc586f89372..834615f13f3e32f5f79498a109949ff77d301741 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 = {