From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] irda: ali-ircc: Fix deadlock in ali_ircc_sir_change_speed() Date: Fri, 11 Sep 2015 16:18:56 -0700 (PDT) Message-ID: <20150911.161856.1635045038995107888.davem@davemloft.net> References: <1442007288-31322-1-git-send-email-khoroshilov@ispras.ru> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: samuel@sortiz.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org To: khoroshilov@ispras.ru Return-path: In-Reply-To: <1442007288-31322-1-git-send-email-khoroshilov@ispras.ru> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Alexey Khoroshilov Date: Sat, 12 Sep 2015 00:34:48 +0300 > ali_ircc_sir_change_speed() is always called with self->lock held, > so acquiring the lock inside it leads to unavoidable deadlock. > > Call graph: > ali_ircc_sir_change_speed() is called from ali_ircc_change_speed() > ali_ircc_fir_hard_xmit() under spin_lock_irqsave(&self->lock, flags); > ali_ircc_sir_hard_xmit() under spin_lock_irqsave(&self->lock, flags); > ali_ircc_net_ioctl() under spin_lock_irqsave(&self->lock, flags); > ali_ircc_dma_xmit_complete() > ali_ircc_fir_interrupt() > ali_ircc_interrupt() under spin_lock(&self->lock); > ali_ircc_sir_write_wakeup() > ali_ircc_sir_interrupt() > ali_ircc_interrupt() under spin_lock(&self->lock); > > The patch removes spin_lock/unlock from ali_ircc_sir_change_speed(). > > Found by Linux Driver Verification project (linuxtesting.org). > > Signed-off-by: Alexey Khoroshilov Looks good, applied, thanks.