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mm/slab: make __free(kfree) accept error pointers
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commit cd7eb8f 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: 54da6a0 ("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>
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Dan Carpenter authored and gregkh committed May 17, 2024
1 parent f395679 commit 79cbe0b
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions include/linux/slab.h
Original file line number Diff line number Diff line change
Expand Up @@ -228,7 +228,7 @@ 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
Expand Down Expand Up @@ -754,7 +754,7 @@ 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);

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