FAILED: patch "[PATCH] mm/slab: make __free(kfree) accept error pointers" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] mm/slab: make __free(kfree) accept error pointers" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x cd7eb8f83fcf258f71e293f7fc52a70be8ed0128
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024051335-botch-pregame-1b8b@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

cd7eb8f83fcf ("mm/slab: make __free(kfree) accept error pointers")
a67d74a4b163 ("mm/slab: Add __free() support for kvfree")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From cd7eb8f83fcf258f71e293f7fc52a70be8ed0128 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@linaro.org>
Date: Sun, 28 Apr 2024 17:26:44 +0300
Subject: [PATCH] mm/slab: make __free(kfree) accept error pointers

Currently, if an automatically freed allocation is an error pointer that
will lead to a crash.  An example of this is in wm831x_gpio_dbg_show().

   171	char *label __free(kfree) = gpiochip_dup_line_label(chip, i);
   172	if (IS_ERR(label)) {
   173		dev_err(wm831x->dev, "Failed to duplicate label\n");
   174		continue;
   175  }

The auto clean up function should check for error pointers as well,
otherwise we're going to keep hitting issues like this.

Fixes: 54da6a092431 ("locking: Introduce __cleanup() based infrastructure")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

diff --git a/include/linux/slab.h b/include/linux/slab.h
index e53cbfa18325..739b21262507 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -266,7 +266,7 @@ void kfree(const void *objp);
 void kfree_sensitive(const void *objp);
 size_t __ksize(const void *objp);
 
-DEFINE_FREE(kfree, void *, if (_T) kfree(_T))
+DEFINE_FREE(kfree, void *, if (!IS_ERR_OR_NULL(_T)) kfree(_T))
 
 /**
  * ksize - Report actual allocation size of associated object
@@ -792,7 +792,7 @@ static inline __alloc_size(1, 2) void *kvcalloc(size_t n, size_t size, gfp_t fla
 extern void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
 		      __realloc_size(3);
 extern void kvfree(const void *addr);
-DEFINE_FREE(kvfree, void *, if (_T) kvfree(_T))
+DEFINE_FREE(kvfree, void *, if (!IS_ERR_OR_NULL(_T)) kvfree(_T))
 
 extern void kvfree_sensitive(const void *addr, size_t len);