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[2.15.156.232]) by smtp.gmail.com with ESMTPSA id z25sm26400850wmk.28.2020.06.28.23.50.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Jun 2020 23:50:18 -0700 (PDT) From: Bartosz Golaszewski To: Jonathan Corbet , Greg Kroah-Hartman , "Rafael J . Wysocki" , Guenter Roeck , Jean Delvare Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v2 4/6] devres: handle zero size in devm_kmalloc() Date: Mon, 29 Jun 2020 08:50:06 +0200 Message-Id: <20200629065008.27620-5-brgl@bgdev.pl> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200629065008.27620-1-brgl@bgdev.pl> References: <20200629065008.27620-1-brgl@bgdev.pl> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Bartosz Golaszewski 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 --- 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, -- 2.26.1