From mboxrd@z Thu Jan 1 00:00:00 1970 From: linus.walleij@linaro.org (Linus Walleij) Date: Thu, 11 May 2017 16:01:54 +0200 Subject: [PATCH] pinctrl: use non-devm kmalloc versions for free functions In-Reply-To: <1493855857-4453-1-git-send-email-andre.przywara@arm.com> References: <1493855857-4453-1-git-send-email-andre.przywara@arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, May 4, 2017 at 1:57 AM, Andre Przywara wrote: > When a pinctrl driver gets interrupted during its probe process > (returning -EPROBE_DEFER), the devres system cleans up all allocated > resources. During this process it calls pinmux_generic_free_functions() > and pinctrl_generic_free_groups(), which in turn use managed kmalloc > calls for temporarily allocating some memory. Now those calls seem to > get added to the devres list, but are apparently not covered by the > cleanup process, because this is actually just running and iterating the > existing list. This leads to those mallocs being left with the device, > which the devres manager complains about when the driver eventually gets > probed again: > [ 0.825239] ------------[ cut here ]------------ > [ 0.825256] WARNING: CPU: 1 PID: 89 at drivers/base/dd.c:349 driver_probe_device+0x2ac/0x2e8 > [ 0.825258] Modules linked in: > [ 0.825262] > [ 0.825270] CPU: 1 PID: 89 Comm: kworker/1:1 Not tainted 4.11.0 #307 > [ 0.825272] Hardware name: Pine64+ (DT) > [ 0.825283] Workqueue: events deferred_probe_work_func > [ 0.825288] task: ffff80007c19c100 task.stack: ffff80007c16c000 > [ 0.825292] PC is at driver_probe_device+0x2ac/0x2e8 > [ 0.825296] LR is at driver_probe_device+0x108/0x2e8 > [ 0.825300] pc : [] lr : [] pstate: 20000045 > .... > This warning is triggered because the devres list is not empty. In this > case the allocations were using 0 bytes, so no real leaks, but still this > ugly warning. > Looking more closely at these *cleanup* functions, devm_kzalloc() is actually > not needed, because the memory is just allocated temporarily and can be > freed just before returning from this function. > So fix this issue by using the bog standard kcalloc() call instead of > devm_kzalloc() and kfree()ing the memory at the end. > > This fixes above warnings on boot, which can be observed on *some* builds > for the Pine64, where the pinctrl driver gets loaded early, but it missing > resources, so gets deferred and is loaded again (successfully) later. > kernelci caught this as well [1]. > > Signed-off-by: Andre Przywara > > [1] https://storage.kernelci.org/net-next/master/v4.11-rc8-2122-gc08bac03d289/arm64/defconfig/lab-baylibre-seattle/boot-sun50i-a64-pine64-plus.html > --- > Hi, > > not sure this is the right fix, I am open to suggestions. I have queued this as a tentative v4.12-rc1 fix, but a bit undertain. Tejun, do I read your comments on the patch as an ACK? Yours, Linus Walleij