Messages in this thread | | | Date | Thu, 11 May 2017 22:02:39 +0800 | Subject | Re: [linux-sunxi] Re: [PATCH] pinctrl: use non-devm kmalloc versions for free functions | From | Icenowy Zheng <> |
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于 2017年5月11日 GMT+08:00 下午10:01:54, Linus Walleij <linus.walleij@linaro.org> 写到: >On Thu, May 4, 2017 at 1:57 AM, Andre Przywara <andre.przywara@arm.com> >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 : [<ffff000008559234>] lr : [<ffff000008559090>] >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 <andre.przywara@arm.com> >> >> [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.
I think 4.11 has also this issue.
> >Tejun, do I read your comments on the patch as an ACK? > >Yours, >Linus Walleij
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