linux-kernel - Re: [PATCH] rtc: stm32: Fix unbalanced clk_disable

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Date:   Sun, 20 Jun 2021 22:33:25 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Martin Fuzzey <martin.fuzzey@...wbird.group>,
        Alessandro Zummo <a.zummo@...ertech.it>
Cc:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-stm32@...md-mailman.stormreply.com,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        linux-kernel@...r.kernel.org,
        Amelie Delaunay <amelie.delaunay@...com>,
        linux-rtc@...r.kernel.org
Subject: Re: [PATCH] rtc: stm32: Fix unbalanced clk_disable_unprepare() on probe error path

On Mon, 7 Jun 2021 19:36:40 +0200, Martin Fuzzey wrote:
> The STM32MP1 RTC may have 2 clocks, the pclk and the rtc_ck.
> 
> If clk_prepare_enable() fails for the second clock (rtc_ck) we must only
> call clk_disable_unprepare() for the first clock (pclk) but currently we
> call it on both leading to a WARN:
> 
> [   15.629568] WARNING: CPU: 0 PID: 146 at drivers/clk/clk.c:958 clk_core_disable+0xb0/0xc8
> [   15.637620] ck_rtc already disabled
> [   15.663322] CPU: 0 PID: 146 Comm: systemd-udevd Not tainted 5.4.77-pknbsp-svn5759-atag-v5.4.77-204-gea4235203137-dirty #2413
> [   15.674510] Hardware name: STM32 (Device Tree Support)
> [   15.679658] [<c0111148>] (unwind_backtrace) from [<c010c0b8>] (show_stack+0x10/0x14)
> [   15.687371] [<c010c0b8>] (show_stack) from [<c0ab3d28>] (dump_stack+0xc0/0xe0)
> [   15.694574] [<c0ab3d28>] (dump_stack) from [<c012360c>] (__warn+0xc8/0xf0)
> [   15.701428] [<c012360c>] (__warn) from [<c0123694>] (warn_slowpath_fmt+0x60/0x94)
> [   15.708894] [<c0123694>] (warn_slowpath_fmt) from [<c053b518>] (clk_core_disable+0xb0/0xc8)
> [   15.717230] [<c053b518>] (clk_core_disable) from [<c053c190>] (clk_core_disable_lock+0x18/0x24)
> [   15.725924] [<c053c190>] (clk_core_disable_lock) from [<bf0adc44>] (stm32_rtc_probe+0x124/0x5e4 [rtc_stm32])
> [   15.735739] [<bf0adc44>] (stm32_rtc_probe [rtc_stm32]) from [<c05f7d4c>] (platform_drv_probe+0x48/0x98)
> [   15.745095] [<c05f7d4c>] (platform_drv_probe) from [<c05f5cec>] (really_probe+0x1f0/0x458)
> [   15.753338] [<c05f5cec>] (really_probe) from [<c05f61c4>] (driver_probe_device+0x70/0x1c4)
> [   15.761584] [<c05f61c4>] (driver_probe_device) from [<c05f6580>] (device_driver_attach+0x58/0x60)
> [   15.770439] [<c05f6580>] (device_driver_attach) from [<c05f6654>] (__driver_attach+0xcc/0x170)
> [   15.779032] [<c05f6654>] (__driver_attach) from [<c05f40d8>] (bus_for_each_dev+0x58/0x7c)
> [   15.787191] [<c05f40d8>] (bus_for_each_dev) from [<c05f4ffc>] (bus_add_driver+0xdc/0x1f8)
> [   15.795352] [<c05f4ffc>] (bus_add_driver) from [<c05f6ed8>] (driver_register+0x7c/0x110)
> [   15.803425] [<c05f6ed8>] (driver_register) from [<c01027bc>] (do_one_initcall+0x70/0x1b8)
> [   15.811588] [<c01027bc>] (do_one_initcall) from [<c01a1094>] (do_init_module+0x58/0x1f8)
> [   15.819660] [<c01a1094>] (do_init_module) from [<c01a0074>] (load_module+0x1e58/0x23c8)
> [   15.827646] [<c01a0074>] (load_module) from [<c01a0860>] (sys_finit_module+0xa0/0xd4)
> [   15.835459] [<c01a0860>] (sys_finit_module) from [<c01011e0>] (__sys_trace_return+0x0/0x20)

Applied, thanks!

[1/1] rtc: stm32: Fix unbalanced clk_disable_unprepare() on probe error path
      commit: 950ac33dbe6ff656a623d862022f0762ec061ba7

Best regards,
-- 
Alexandre Belloni <alexandre.belloni@...tlin.com>