From cad064f1bd5237481d15b72b481809e3f0907dd9 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Mon, 29 Jun 2020 08:50:06 +0200 Subject: [PATCH] devres: handle zero size in devm_kmalloc() Make devm_kmalloc() behave similarly to non-managed kmalloc(): return ZERO_SIZE_PTR when requested size is 0. Update devm_kfree() to handle this case. Signed-off-by: Bartosz Golaszewski Link: https://lore.kernel.org/r/20200629065008.27620-5-brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman --- drivers/base/devres.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/base/devres.c b/drivers/base/devres.c index 1df1fb10b2d9..ed615d3b9cf1 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -819,6 +819,9 @@ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) { struct devres *dr; + if (unlikely(!size)) + return ZERO_SIZE_PTR; + /* use raw alloc_dr for kmalloc caller tracing */ dr = alloc_dr(devm_kmalloc_release, size, gfp, dev_to_node(dev)); if (unlikely(!dr)) @@ -950,10 +953,10 @@ void devm_kfree(struct device *dev, const void *p) int rc; /* - * Special case: pointer to a string in .rodata returned by - * devm_kstrdup_const(). + * Special cases: pointer to a string in .rodata returned by + * devm_kstrdup_const() or NULL/ZERO ptr. */ - if (unlikely(is_kernel_rodata((unsigned long)p))) + if (unlikely(is_kernel_rodata((unsigned long)p) || ZERO_OR_NULL_PTR(p))) return; rc = devres_destroy(dev, devm_kmalloc_release, -- 2.11.0