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Sun, 19 Apr 2026 05:32:30 -0700 (PDT) Date: Sun, 19 Apr 2026 18:02:26 +0530 From: Sanjay Chitroda To: Andy Shevchenko CC: jic23@kernel.org, dlechner@baylibre.com, nuno.sa@analog.com, andy@kernel.org, tglx@kernel.org, christophe.jaillet@wanadoo.fr, mingo@kernel.org, nabijaczleweli@nabijaczleweli.xyz, kees@kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_v6_4/7=5D_iio=3A_ssp=5Fsensors=3A_dr?= =?US-ASCII?Q?op_duplicated_wdt_timer_and_work_cleanup?= User-Agent: Thunderbird for Android In-Reply-To: References: <20260415050749.3858046-1-sanjayembedded@gmail.com> <20260415050749.3858046-5-sanjayembedded@gmail.com> Message-ID: <2CA4C4F2-6BC8-4970-B2D7-FCC67DE16C41@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 15 April 2026 2:59:55=E2=80=AFpm IST, Andy Shevchenko wrote: >On Wed, Apr 15, 2026 at 10:37:46AM +0530, Sanjay Chitroda wrote: > >> The SSP remove path cleans up the watchdog timer and associated work >> both via ssp_disable_wdt_timer() and through explicit timer and work >> teardown=2E >>=20 >> Remove the duplicated timer_delete_sync() and cancel_work_sync() >> calls and rely on ssp_disable_wdt_timer() as the single cleanup helper >> to simplify the remove path=2E >>=20 >> No functional change intended=2E > >=2E=2E=2E > >> ssp_enable_mcu(data, false); >> - ssp_disable_wdt_timer(data); >> - >> ssp_clean_pending_list(data); >> =20 >> free_irq(data->spi->irq, data); >> =20 >> - timer_delete_sync(&data->wdt_timer); >> - cancel_work_sync(&data->work_wdt); >> + ssp_disable_wdt_timer(data); > >Hmm=2E=2E=2E I'm not sure it doesn't change the behaviour=2E First of all= , the >difference is that IRQ handler may be involved in the timer and/or work= =2E > >This patch needs much better investigation conducted and commit message >provided with explanation of all possible race conditions and why they >don't happen=2E Also I am not sure if this dup is a mistake or deliberate >action (again, it's all related to the timings of IRQ handler, timer job, >and work and how they are relies on each other data/flow)=2E > Thank you Andy for the input=2E You are right patch has changed teardown ordering by moving watchdog stop = after free_irq(), so "no functional change" is wrong=2E I will send next series change by removing duplicate timer/work cleanup af= ter free_irq()=2E Race analysis, - wdt_timer can queue work_wdt - free_irq() handle IRQ, but does not cancel timer/work=2E Therefore timer= /work needs to explicitly cancelled before IRQ release=2E Along with change I will also add analysis in commit message=2E >