From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH] clocksource: Do not drop unheld reference on device node Date: Fri, 22 Nov 2013 17:31:46 +0100 Message-ID: <528F86F2.40706@linaro.org> References: <1382136588-15320-1-git-send-email-treding@nvidia.com> <20131122161607.GA5088@ulmo.nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20131122161607.GA5088@ulmo.nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding , Thomas Gleixner Cc: Arnd Bergmann , Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?B?VXdl?= =?UTF-8?B?IEtsZWluZS1Lw7ZuaWc=?= , David Brown List-Id: devicetree@vger.kernel.org On 11/22/2013 05:16 PM, Thierry Reding wrote: > On Sat, Oct 19, 2013 at 12:49:48AM +0200, Thierry Reding wrote: >> When booting a recent kernel on ARM with OF_DYNAMIC enabled, the ker= nel >> warns about the following: >> >> [ 0.000000] ERROR: Bad of_node_put() on /timer@50004600 >> [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.0-rc5= -next-20131017-00077-gedfd827-dirty #406 >> [ 0.000000] [] (unwind_backtrace+0x0/0xf4) from [] (show_stack+0x10/0x14) >> [ 0.000000] [] (show_stack+0x10/0x14) from [= ] (dump_stack+0x9c/0xc8) >> [ 0.000000] [] (dump_stack+0x9c/0xc8) from [= ] (of_node_release+0x90/0x9c) >> [ 0.000000] [] (of_node_release+0x90/0x9c) from [] (of_find_matching_node_and_match+0x78/0xb4) >> [ 0.000000] [] (of_find_matching_node_and_match+0x78/0= xb4) from [] (clocksource_of_init+0x60/0x70) >> [ 0.000000] [] (clocksource_of_init+0x60/0x70) from [<= c076e99c>] (start_kernel+0x1f4/0x33c) >> [ 0.000000] [] (start_kernel+0x1f4/0x33c) from [<80008= 074>] (0x80008074) >> >> This is caused by clocksource_of_init() dropping a reference on the >> device node that it never took. The reference taken by the loop is >> implicitly dropped on subsequent iterations. See the implementation = of >> and the comment on top of the of_find_matching_node_and_match() >> function for reference (no pun intended). >> >> Signed-off-by: Thierry Reding >> --- >> drivers/clocksource/clksrc-of.c | 1 - >> 1 file changed, 1 deletion(-) > > Can someone look at this? Yes. Sounds like I missed it. This regression has been introduced by: commit 326e31eebe61dc838e031ea16968b2cfb43443e3 Author: Uwe Kleine-K=C3=B6nig Date: Tue Oct 1 11:00:53 2013 +0200 clocksource: Put nodes passed to CLOCKSOURCE_OF_DECLARE callbacks=20 centrally Instead of letting each driver call of_node_put do it centrally in= the loop that also calls the CLOCKSOURCE_OF_DECLARE callbacks. This is= less prone to error and also moves getting and putting the references=20 into the same function. Consequently all respective of_node_put calls in drivers are remov= ed. Signed-off-by: Uwe Kleine-K=C3=B6nig Signed-off-by: Daniel Lezcano Acked-by: David Brown >> diff --git a/drivers/clocksource/clksrc-of.c b/drivers/clocksource/c= lksrc-of.c >> index 35639cf4..b9ddd9e 100644 >> --- a/drivers/clocksource/clksrc-of.c >> +++ b/drivers/clocksource/clksrc-of.c >> @@ -35,6 +35,5 @@ void __init clocksource_of_init(void) >> >> init_func =3D match->data; >> init_func(np); >> - of_node_put(np); >> } >> } >> -- >> 1.8.4 >> --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog