[PATCH 6.1 205/236] mm/slab: make __free(kfree) accept error pointers

Greg Kroah-Hartman
2024-05-14T11:37:13Z

From: Dan Carpenter <dan.carpenter@linaro.org>

commit cd7eb8f83fcf258f71e293f7fc52a70be8ed0128 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/slab.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -198,7 +198,7 @@ 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