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 62EBD3B2FDD; Thu, 25 Jun 2026 12:08:11 +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=1782389293; cv=none; b=ToxZV0UjJ2XsCCJF+Zb+fx2lTFawLzYfGZJ6T9cS3+goNqSzabbibCXtPuIW+MNHyPmfVcaFnnsNcN9waG14wJhxksBHzuVZFX84UN/hePchiiyDuJWkJC/ZBc4RBugLNxeCRb8ZGURSTa+9QtmE5/Xwax0H6okhJYvcYInTej8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782389293; c=relaxed/simple; bh=OsyQ+vo7enYntqm19GlzFbD+ElNCoozlJdx4rCJfqIE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=K1YuSMNDtsL0W7szSZx5C/iA0gCdw/ffuHjKG1bqgJPWykjt5UkypWUA8CnSmU+0O2hGt1Hj+654Qmae0oR+vJb0kh3mkaSx9z6MM97lhjzBZkDMYpAdT2S4HdLDAeBRaYgrjvR6Hx2kQCQo9JjB+K/LlSmqCZ+6w49Qh6rZHhw= 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=FVwLDUQg 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="FVwLDUQg" Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id E8734170204; Thu, 25 Jun 2026 14:57:48 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baodeep.com; s=dkim; t=1782388682; h=from:subject:date:message-id:to:cc:mime-version: content-transfer-encoding; bh=00CUa1hLOxEqnOirfYovjxZeJiCqa/8wDLtlYF68e/4=; b=FVwLDUQg38OHClWg9cUHgYBGktXMqDZPZCwwoJ9oX7Qt88x+OESMSiKIn7T/LMKJhdmMoG dfaJgroBqEsxQ5NoRGrKXR7wvMyIh1PEpA00xDqGKI0NBfYSQCya4iw8TI9PS/BUeDWDpe FJ9a5xU6+owdAoVcMT29AbK2vuY7rMA+xOcbpfxBbHrrvC85n0zfSplNogiTMs5SrnuVXo 47LbZadKDKaEZ409wu/jERSTth437wrdLdodtjYISi20O07ynWp6w488Rbxf9G8iVDvs0G yAwUAeZnQxJ+MIPyebGomtI0WUxWBa3vPJQSTANN8qGdJwt/eXiTLJ5VXgnwdA== 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 v2 0/2] gpio: fix sleeping-in-atomic in shared-proxy; restore meson non-sleeping Date: Thu, 25 Jun 2026 14:57:16 +0300 Message-ID: <20260625115718.1678991-1-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 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. No functional change. v1: https://lore.kernel.org/linux-gpio/20260610153329.937833-1-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 | 66 +++++++++++---------------- drivers/gpio/gpiolib-shared.c | 9 +--- drivers/gpio/gpiolib-shared.h | 28 +----------- drivers/pinctrl/meson/pinctrl-meson.c | 2 +- 4 files changed, 30 insertions(+), 75 deletions(-) base-commit: 840ef6c78e6a2f694b578ecb9063241c992aaa9e -- 2.54.0