From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx.adeep.su (mx.adeep.su [185.250.0.168]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BFB143EFFD5; Tue, 30 Jun 2026 10:16:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.250.0.168 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782814593; cv=none; b=I2tI4+fIxzHwDztvpT85xcUkrT1Og6sPXT0hEdgJeQp0eW1vh6lpVyZgUf8pwC7/lpe30sGTy5p/tKl3i4iKDEkCXzlvt6tnkIYgPZE55esIZDgsrugIIhspWanAy/+2FjB+LTUcFWYg4mMTf7SWi3yE3thwvA0osJP2BJOCBB8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782814593; c=relaxed/simple; bh=zi1xEpvM1ZjiGj+ROwM/4ktLOPRCEThBMSmgtwizAFQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ojdumP4tpbyy62dJc2IcSj6bsQL1sZWvAXS+kXjMh1ZbBaxg17+Fvnhb8CE6GqzoSlB0iLcMAFwZ62CLt+OlVMP947MxyCHb4a39ucPuAmzhMXZ7svJURIGe5VlrK5HKkAqilrMFVfRFarXsmamiget/4blPpBCldEqZqcfwEcM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=baodeep.com; spf=pass smtp.mailfrom=baodeep.com; dkim=fail (2048-bit key) header.d=baodeep.com header.i=@baodeep.com header.b=jC5ljsv/ reason="signature verification failed"; arc=none smtp.client-ip=185.250.0.168 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=baodeep.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=baodeep.com Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=baodeep.com header.i=@baodeep.com header.b="jC5ljsv/" Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 2DC1D1CD0CC; Tue, 30 Jun 2026 13:16:13 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baodeep.com; s=dkim; t=1782814585; h=from:subject:date:message-id:to:cc:mime-version: content-transfer-encoding; bh=wN+EcU0gGHH33bhyn/gHbeG7JZHnwpKvV3LKnR2eWeM=; b=jC5ljsv/fRpC1AtIMayTHfeg0yZ0qKe3UHL+ssTZe5GiIleQX+Myb6i/5wARIpwukmdGOf QJFTuIGKV2MQA1M310phV3qVyA9mZj4j+mkUfT+Lk2N2zJFDQ33btXi9eLN9nKLrjsuI2h Vpp9lVjL/GB8xT7JYAQCPHwIC+p2HgwuMxU9fm51+i5RZ/59eWzCwm5pkFD7KpLYKIbVBB lDdzflPJ1asiQxq3co7fi2OEu6pYO6S4941wKqhNEVy3amf5Ugu7qy/33HiTr54wp3mTSC xtoSlGgBlLk6G/ebVuEnv+A4NnxvrXG6JL9zAQSkPYBPDwuDbU73oPWgzDHgVA== From: Viacheslav Bocharov To: Linus Walleij , Bartosz Golaszewski Cc: Neil Armstrong , Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Marek Szyprowski , Robin Murphy , Diederik de Haas , linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 0/2] gpio: fix sleeping-in-atomic in shared-proxy; restore meson non-sleeping Date: Tue, 30 Jun 2026 13:15:43 +0300 Message-ID: <20260630101545.800625-1-v@baodeep.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 gpio-shared-proxy chooses its descriptor lock (mutex vs spinlock) from the underlying chip's can_sleep, but under that lock it calls config and direction ops that reach sleeping pinctrl paths. On a controller with non-sleeping MMIO value ops the lock is a spinlock, so a sleeping call runs from atomic context: BUG: sleeping function called from invalid context ... pinctrl_gpio_set_config <- gpiochip_generic_config <- gpio_shared_proxy_set_config (voting spinlock held) <- ... <- mmc_pwrseq_simple_probe This was reported on Khadas VIM3 and worked around for Amlogic by commit 28f240683871 ("pinctrl: meson: mark the GPIO controller as sleeping"), which marked the whole meson controller sleeping. That workaround broke atomic value-path consumers: w1-gpio (1-Wire bitbang) no longer detects devices, because its IRQ-disabled read slot calls the non-cansleep gpiod_*_value() and now hits WARN_ON(can_sleep) per bit. Patch 1 fixes the proxy locking generically (always a sleeping mutex). Patch 2 then restores meson can_sleep=false, fixing 1-Wire. Patch 1 has a trade-off: a proxied GPIO becomes sleeping, so consumers gating on gpiod_cansleep() change behaviour. No current device needs atomic (non-cansleep) value access on a shared GPIO -- every report (Khadas VIM3, ODROID-M1, my test on JetHub D1+) is a shared reset line (eMMC/SDIO pwrseq or PCIe reset) driven through the cansleep accessors, which is what the proxy exists to vote on; bit-banging that needs atomic access cannot work through voting anyway. An alternative that keeps atomic value access (split locking) is possible but adds a second lock and new race windows, so this series takes the simpler mutex-only approach. The two are a unit: patch 2 must not be applied without patch 1, otherwise the original VIM3 splat returns on boards that share a meson GPIO -- please keep the order. I have not Cc'd stable; I will request stable backports separately once both patches have landed. Changes since v2: - gpio: shared-proxy: drop the set_func callback from gpio_shared_proxy_set_unlocked() and call gpiod_set_value_cansleep() directly. The shared direction_output path drives the already-output line through the value setter instead of re-issuing gpiod_direction_output() (equivalent, minus a redundant per-edge re-assert of drive config/bias). No change to the voting/value behaviour. Changes since v1: - gpio: shared-proxy: open-code the descriptor mutex; drop the gpio_shared_desc_lock guard and the gpio_shared_lockdep_assert() helper, move the mutex rationale to the can_sleep assignment. v1: https://lore.kernel.org/linux-gpio/20260610153329.937833-1-v@baodeep.com/ v2: https://lore.kernel.org/linux-gpio/20260625115718.1678991-1-v@baodeep.com/ Viacheslav Bocharov (2): gpio: shared-proxy: always serialize with a sleeping mutex pinctrl: meson: restore non-sleeping GPIO access drivers/gpio/gpio-shared-proxy.c | 76 ++++++++++----------------- drivers/gpio/gpiolib-shared.c | 9 +--- drivers/gpio/gpiolib-shared.h | 28 +--------- drivers/pinctrl/meson/pinctrl-meson.c | 2 +- 4 files changed, 33 insertions(+), 82 deletions(-) base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482 -- 2.54.0