On Wed, 25 Nov 2020 at 09:05, Oleksandr Natalenko oleksandr@natalenko.name wrote:

Hello.

On 25.11.2020 08:53, Ard Biesheuvel wrote:

...

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

Should also have:

Cc: stable@vger.kernel.org # v5.9

No it should not. The fixes tag should be sufficient.

...

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

---

fs/efivarfs/inode.c | 1 + fs/efivarfs/super.c | 1 - 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c index 96c0c86f3fff..38324427a2b3 100644 --- a/fs/efivarfs/inode.c +++ b/fs/efivarfs/inode.c @@ -103,6 +103,7 @@ 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 f943fd0b0699..15880a68faad 100644 --- 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 = {

-- Oleksandr Natalenko (post-factum)