From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793213866; b=E63rV11cmvPU89pBjZE+9hwInczvevzh5Qyl42pUFUx8HCo0GxJxpylV5JSg+kWgqCWO VcoQTzAA9k2SyeaAr5p17XDZuGssHgyrrSL4JyvCTN22s6NBqICWnIkz85HXIxprLNktw P1lXA1ibWhjS15lT7y5dl4K1+pWJm+4q0EEmkpZtkRnm+Y7KY3GVhAkpJRVjJlB2s30ks 2LgcZ+ia8RXtmzG6swRUUXM2r4gQK0bEitTHuRcjtK5pp9eZ4WJt0qLFBrxppq+sfIrgj 86epTdTlztpanS9keFNtCUjcqpzDk2GF2SXrfOaYs80tuooOkATD8aIBkHui25Q6ITA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793213866; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=T/wN5CUgzesZ+8LcJmTaSGcBuGehPtSMmAEXtG/fjM8=; b=CU4568778fnCu6bX/7vvNRQ+ctJyuCvtgdAnDKy2ecqSOY9UloNP6C1wD8af6lO/XZz/ 3VhBdK9qAD+bZ7ELAxLo7q4Ae/ylji42pvhGyf/iJmy8Nnahp1FDEMeY0/Vg96hk8cOWh aVIhq3+GL0B5qfcCPEGs0zjuzHXX1C/0YX8XAZfOUBu93E+7dtS97KauGPmQhKpMVNCzK AVta/swgw4UbZy49YC4hedYby5slx6tORUPSxcLIdCT0Io+Ap0Iy+Ic8bA1k9E5ghcaAu 1AMPakYHLblJzMkTB5JAQhKXQfwNVa+rm4uRJRzRPRS0MwfKe8r/56JXthGKMzfkPjQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zZRzg2gV; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 805A6606A31C; Wed, 28 Oct 2026 18:57:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zZRzg2gV Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0E8B1F01825; Wed, 28 Oct 2026 18:57:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793213866; bh=T/wN5CUgzesZ+8LcJmTaSGcBuGehPtSMmAEXtG/fjM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=zZRzg2gVkLMvd3z1aeWhNRkBZdsE33UmabuBudr1iFdntgN8vb5OtP5IMafrn3pLO ziBcv3b4Oc1coO2i5zRSnV1KtXF7y7NVYaXI55RBYnU/zdrxIJ5khwiZ3SlXsG91e2 SxNLCaUuT4mXRNKYwZbvYpefYmNyKyY6fHRaP6Ng= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mukesh Ojha , Linus Walleij , Sasha Levin Subject: [PATCH 6.1 0656/1887] pinmux: Use sequential access to access desc->pinmux data Date: Wed, 28 Oct 2026 17:45:52 +0100 Message-ID: <20261028170514.339408587@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mukesh Ojha [ Upstream commit 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e ] When two client of the same gpio call pinctrl_select_state() for the same functionality, we are seeing NULL pointer issue while accessing desc->mux_owner. Let's say two processes A, B executing in pin_request() for the same pin and process A updates the desc->mux_usecount but not yet updated the desc->mux_owner while process B see the desc->mux_usecount which got updated by A path and further executes strcmp and while accessing desc->mux_owner it crashes with NULL pointer. Serialize the access to mux related setting with a mutex lock. cpu0 (process A) cpu1(process B) pinctrl_select_state() { pinctrl_select_state() { pin_request() { pin_request() { ... .... } else { desc->mux_usecount++; desc->mux_usecount && strcmp(desc->mux_owner, owner)) { if (desc->mux_usecount > 1) return 0; desc->mux_owner = owner; } } Signed-off-by: Mukesh Ojha Link: https://lore.kernel.org/20241014192930.1539673-1-quic_mojha@quicinc.com Signed-off-by: Linus Walleij Signed-off-by: Sasha Levin --- drivers/pinctrl/core.c | 3 + drivers/pinctrl/core.h | 1 + drivers/pinctrl/pinmux.c | 173 ++++++++++++++++++++++----------------- 3 files changed, 100 insertions(+), 77 deletions(-) diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index 03bfdcbc3325d..1c3dcb270ea07 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -221,6 +221,9 @@ static int pinctrl_register_one_pin(struct pinctrl_dev *pctldev, /* Set owner */ pindesc->pctldev = pctldev; +#ifdef CONFIG_PINMUX + mutex_init(&pindesc->mux_lock); +#endif /* Copy basic pin info */ if (pin->name) { diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h index 840103c40c14a..f5e4ca19c17b2 100644 --- a/drivers/pinctrl/core.h +++ b/drivers/pinctrl/core.h @@ -167,6 +167,7 @@ struct pin_desc { const char *mux_owner; const struct pinctrl_setting_mux *mux_setting; const char *gpio_owner; + struct mutex mux_lock; #endif }; diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index 0cbf698d16db5..782d7d4204ad1 100644 --- a/drivers/pinctrl/pinmux.c +++ b/drivers/pinctrl/pinmux.c @@ -13,6 +13,7 @@ #define pr_fmt(fmt) "pinmux core: " fmt #include +#include #include #include #include @@ -90,6 +91,7 @@ bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned pin) if (!desc || !ops) return true; + guard(mutex)(&desc->mux_lock); if (ops->strict && desc->mux_usecount) return false; @@ -124,29 +126,31 @@ static int pin_request(struct pinctrl_dev *pctldev, dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n", pin, desc->name, owner); - if ((!gpio_range || ops->strict) && - desc->mux_usecount && strcmp(desc->mux_owner, owner)) { - dev_err(pctldev->dev, - "pin %s already requested by %s; cannot claim for %s\n", - desc->name, desc->mux_owner, owner); - goto out; - } + scoped_guard(mutex, &desc->mux_lock) { + if ((!gpio_range || ops->strict) && + desc->mux_usecount && strcmp(desc->mux_owner, owner)) { + dev_err(pctldev->dev, + "pin %s already requested by %s; cannot claim for %s\n", + desc->name, desc->mux_owner, owner); + goto out; + } - if ((gpio_range || ops->strict) && desc->gpio_owner) { - dev_err(pctldev->dev, - "pin %s already requested by %s; cannot claim for %s\n", - desc->name, desc->gpio_owner, owner); - goto out; - } + if ((gpio_range || ops->strict) && desc->gpio_owner) { + dev_err(pctldev->dev, + "pin %s already requested by %s; cannot claim for %s\n", + desc->name, desc->gpio_owner, owner); + goto out; + } - if (gpio_range) { - desc->gpio_owner = owner; - } else { - desc->mux_usecount++; - if (desc->mux_usecount > 1) - return 0; + if (gpio_range) { + desc->gpio_owner = owner; + } else { + desc->mux_usecount++; + if (desc->mux_usecount > 1) + return 0; - desc->mux_owner = owner; + desc->mux_owner = owner; + } } /* Let each pin increase references to this module */ @@ -177,12 +181,14 @@ static int pin_request(struct pinctrl_dev *pctldev, out_free_pin: if (status) { - if (gpio_range) { - desc->gpio_owner = NULL; - } else { - desc->mux_usecount--; - if (!desc->mux_usecount) - desc->mux_owner = NULL; + scoped_guard(mutex, &desc->mux_lock) { + if (gpio_range) { + desc->gpio_owner = NULL; + } else { + desc->mux_usecount--; + if (!desc->mux_usecount) + desc->mux_owner = NULL; + } } } out: @@ -218,15 +224,17 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin, return NULL; } - if (!gpio_range) { - /* - * A pin should not be freed more times than allocated. - */ - if (WARN_ON(!desc->mux_usecount)) - return NULL; - desc->mux_usecount--; - if (desc->mux_usecount) - return NULL; + scoped_guard(mutex, &desc->mux_lock) { + if (!gpio_range) { + /* + * A pin should not be freed more times than allocated. + */ + if (WARN_ON(!desc->mux_usecount)) + return NULL; + desc->mux_usecount--; + if (desc->mux_usecount) + return NULL; + } } /* @@ -238,13 +246,15 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin, else if (ops->free) ops->free(pctldev, pin); - if (gpio_range) { - owner = desc->gpio_owner; - desc->gpio_owner = NULL; - } else { - owner = desc->mux_owner; - desc->mux_owner = NULL; - desc->mux_setting = NULL; + scoped_guard(mutex, &desc->mux_lock) { + if (gpio_range) { + owner = desc->gpio_owner; + desc->gpio_owner = NULL; + } else { + owner = desc->mux_owner; + desc->mux_owner = NULL; + desc->mux_setting = NULL; + } } module_put(pctldev->owner); @@ -458,7 +468,8 @@ int pinmux_enable_setting(const struct pinctrl_setting *setting) pins[i]); continue; } - desc->mux_setting = &(setting->data.mux); + scoped_guard(mutex, &desc->mux_lock) + desc->mux_setting = &(setting->data.mux); } ret = ops->set_mux(pctldev, setting->data.mux.func, @@ -472,8 +483,10 @@ int pinmux_enable_setting(const struct pinctrl_setting *setting) err_set_mux: for (i = 0; i < num_pins; i++) { desc = pin_desc_get(pctldev, pins[i]); - if (desc) - desc->mux_setting = NULL; + if (desc) { + scoped_guard(mutex, &desc->mux_lock) + desc->mux_setting = NULL; + } } err_pin_request: /* On error release all taken pins */ @@ -492,6 +505,7 @@ void pinmux_disable_setting(const struct pinctrl_setting *setting) unsigned num_pins = 0; int i; struct pin_desc *desc; + bool is_equal; if (pctlops->get_group_pins) ret = pctlops->get_group_pins(pctldev, setting->data.mux.group, @@ -517,7 +531,10 @@ void pinmux_disable_setting(const struct pinctrl_setting *setting) pins[i]); continue; } - if (desc->mux_setting == &(setting->data.mux)) { + scoped_guard(mutex, &desc->mux_lock) + is_equal = (desc->mux_setting == &(setting->data.mux)); + + if (is_equal) { pin_free(pctldev, pins[i], NULL); } else { const char *gname; @@ -609,40 +626,42 @@ static int pinmux_pins_show(struct seq_file *s, void *what) if (desc == NULL) continue; - if (desc->mux_owner && - !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev))) - is_hog = true; - - if (pmxops->strict) { - if (desc->mux_owner) - seq_printf(s, "pin %d (%s): device %s%s", - pin, desc->name, desc->mux_owner, + scoped_guard(mutex, &desc->mux_lock) { + if (desc->mux_owner && + !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev))) + is_hog = true; + + if (pmxops->strict) { + if (desc->mux_owner) + seq_printf(s, "pin %d (%s): device %s%s", + pin, desc->name, desc->mux_owner, + is_hog ? " (HOG)" : ""); + else if (desc->gpio_owner) + seq_printf(s, "pin %d (%s): GPIO %s", + pin, desc->name, desc->gpio_owner); + else + seq_printf(s, "pin %d (%s): UNCLAIMED", + pin, desc->name); + } else { + /* For non-strict controllers */ + seq_printf(s, "pin %d (%s): %s %s%s", pin, desc->name, + desc->mux_owner ? desc->mux_owner + : "(MUX UNCLAIMED)", + desc->gpio_owner ? desc->gpio_owner + : "(GPIO UNCLAIMED)", is_hog ? " (HOG)" : ""); - else if (desc->gpio_owner) - seq_printf(s, "pin %d (%s): GPIO %s", - pin, desc->name, desc->gpio_owner); + } + + /* If mux: print function+group claiming the pin */ + if (desc->mux_setting) + seq_printf(s, " function %s group %s\n", + pmxops->get_function_name(pctldev, + desc->mux_setting->func), + pctlops->get_group_name(pctldev, + desc->mux_setting->group)); else - seq_printf(s, "pin %d (%s): UNCLAIMED", - pin, desc->name); - } else { - /* For non-strict controllers */ - seq_printf(s, "pin %d (%s): %s %s%s", pin, desc->name, - desc->mux_owner ? desc->mux_owner - : "(MUX UNCLAIMED)", - desc->gpio_owner ? desc->gpio_owner - : "(GPIO UNCLAIMED)", - is_hog ? " (HOG)" : ""); + seq_putc(s, '\n'); } - - /* If mux: print function+group claiming the pin */ - if (desc->mux_setting) - seq_printf(s, " function %s group %s\n", - pmxops->get_function_name(pctldev, - desc->mux_setting->func), - pctlops->get_group_name(pctldev, - desc->mux_setting->group)); - else - seq_putc(s, '\n'); } mutex_unlock(&pctldev->mutex); -- 2.53.0