From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Mon, 14 Sep 2015 16:40:28 +0200 Subject: [PATCH 2/2] clk: at91: system: don't try to free_irq when there is no IRQ In-Reply-To: <1441982047-11303-2-git-send-email-alexandre.belloni@free-electrons.com> References: <1441982047-11303-1-git-send-email-alexandre.belloni@free-electrons.com> <1441982047-11303-2-git-send-email-alexandre.belloni@free-electrons.com> Message-ID: <20150914164028.7f38505d@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Alexandre, On Fri, 11 Sep 2015 16:34:07 +0200 Alexandre Belloni wrote: > In the error path of at91_clk_register_system(), sys->irq is freed > unconditionally but it may not exist or be request at all. Not sure this is really needed since free_irq() seems to gracefully handle the case where the irq has not been previously requested [1] (it does not complain about invalid irq descriptors), but I guess this extra check cannot hurt. BTW, that's kinda weird that free_irq() accepts this case, but complains when you're trying to free a wrong (or already freed) shared irq handler [2]. Acked-by: Boris Brezillon Best Regards, Boris [1]http://lxr.free-electrons.com/source/kernel/irq/manage.c#L1471 [2]http://lxr.free-electrons.com/source/kernel/irq/manage.c#L1377 > > Signed-off-by: Alexandre Belloni > --- > drivers/clk/at91/clk-system.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/at91/clk-system.c b/drivers/clk/at91/clk-system.c > index 58008b3e8bc1..3f5314344286 100644 > --- a/drivers/clk/at91/clk-system.c > +++ b/drivers/clk/at91/clk-system.c > @@ -138,7 +138,8 @@ at91_clk_register_system(struct at91_pmc *pmc, const char *name, > > clk = clk_register(NULL, &sys->hw); > if (IS_ERR(clk)) { > - free_irq(sys->irq, sys); > + if (irq) > + free_irq(sys->irq, sys); > kfree(sys); > } > -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com