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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="T2tCDB/a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BD421F000E9; Fri, 14 Aug 2026 05:14:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786684494; bh=0tabxgf2HqNhSwGzmW0+5bJFHR/phfXBWPKnsW3RNhY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=T2tCDB/agh63veMMOhnw/iRUveYvHD6bwoBeBDh6RyU1K+j74Zzem96OFNNzZhJNx djMN0zmuEB8G5Yv2wf8f+xiTDws0EOGn7oR15Hfy66ggLdRn2ia7ftedCUDzBF+EG2 IRMALNeyCtC2/i6SSxYk/aRdUnYaSzruvk7jvZWsrmLm2CCJwIE6Ku4/vV1uooLJBY x/J+8J1PYTRpGYmXEZKBl0XtYnZrVYaAS/cRs7X+8aYFRqrVe5J3Ct+etUiHoy1WQ1 nrjsf6KXQXcp63Bz29cTQEV8PPt5b0D2U9V1KEXxFK2ES2yg1gS7xKURhLJtTkgA5F 19NZlwY3PnUPA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v14 28/38] phy: core: add notifier infrastructure Reply-To: sashiko-reviews@lists.linux.dev To: "Sebastian Reichel" Cc: robh@kernel.org, conor+dt@kernel.org, devicetree@vger.kernel.org, vkoul@kernel.org, neil.armstrong@linaro.org, olteanv@gmail.com, linux-phy@lists.infradead.org In-Reply-To: <20260813-rockchip-usbdp-cleanup-v14-28-b5ad9c68fa11@collabora.com> References: <20260813-rockchip-usbdp-cleanup-v14-0-b5ad9c68fa11@collabora.com> <20260813-rockchip-usbdp-cleanup-v14-28-b5ad9c68fa11@collabora.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 14 Aug 2026 05:14:53 +0000 Message-Id: <20260814051453.9BD421F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] AB-BA lock inversion deadlock between PHY consumer state locks and= phy->mutex via synchronous notifier. -- --- Patch [28]: [PATCH v14 28/38] phy: core: add notifier infrastructure --- commit 140d5ba0c3927a01cec06534c2dc22cf14579ba0 Author: Sebastian Reichel phy: core: add notifier infrastructure This commit introduces a notifier API for PHY devices, allowing consumer drivers to hook into PHY reset events. This provides a mechanism for consum= ers to gracefully handle the PHY going down during configuration or orientation changes. > diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c > index 21aaf2f76e53e..51d261daae7a9 100644 > --- a/drivers/phy/phy-core.c > +++ b/drivers/phy/phy-core.c [ ... ] > @@ -542,6 +542,70 @@ int phy_notify_state(struct phy *phy, union phy_noti= fy state) [ ... ] > +/** > + * phy_notify_reset() - notify consumers of a PHY reset event > + * @phy: the phy that is being reset > + * @event: the notification event (PRE_RESET or POST_RESET) > + * > + * Called by PHY providers to notify consumers that the PHY is about to > + * be reset or has completed a reset. This allows consumers to quiesce > + * hardware before the PHY becomes unavailable. > + * > + * This may be called from within PHY provider callbacks (e.g. set_mode, > + * power_on) where phy->mutex is held. Consumer notification handlers mu= st > + * therefore NOT call back into the PHY framework (e.g. phy_power_off, > + * phy_exit) on the same PHY, as this would result in a deadlock. > + * > + * Returns: %0 if successful or no notifiers registered, a negative error > + * code if a notifier returns an error (for PRE_RESET only) > + */ > +int phy_notify_reset(struct phy *phy, enum phy_notification event) > +{ > + int ret; > + > + if (!phy) > + return 0; > + > + ret =3D blocking_notifier_call_chain(&phy->notifier, event, phy); [Severity: High] Does this synchronous notification under phy->mutex introduce an AB-BA lock inversion risk with consumer driver state locks? For example, if a multi-port PHY has multiple consumers (like DP and USB), Consumer A could acquire its driver state lock (e.g., dp_lock) and call phy_power_on(phy), blocking on phy->mutex. Concurrently, if Consumer B triggers a phy_set_mode(phy) call, the PHY core acquires phy->mutex and invokes the provider's callback, which in turn calls phy_notify_reset(). This synchronously invokes Consumer A's notifier callba= ck via blocking_notifier_call_chain(). If Consumer A attempts to acquire its state lock (dp_lock) within the notif= ier callback to safely quiesce its hardware, it will deadlock. Is it safe to ex= ecute this blocking notifier chain while holding phy->mutex? > + return notifier_to_errno(ret); > +} > +EXPORT_SYMBOL_GPL(phy_notify_reset); --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260813-rockchip-u= sbdp-cleanup-v14-0-b5ad9c68fa11@collabora.com?part=3D28