From nobody Mon Dec 15 23:31:21 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DD38D346A07; Mon, 15 Dec 2025 14:21:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765808498; cv=none; b=RqrVhZG1ZKhKSf8PS+nGj1YHvnmX8L+EbiYr6AnxMWltvWv/o+N/PS3VyiHAgNVxe69v20SfnY2r3G0oaPufmGLXf6CO4FlyOZU39U2zTCRwuYeUCAYnnsaHgXvJAwegXOwkicxoUSTJ17HGRLHokBed7G61Nsp33DkwrIIHYwg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765808498; c=relaxed/simple; bh=MTKeMG3Bg3HAsEC7hfWzoaJNW/z6vXP7y9UpwJgb2Xs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GZs+8ZCcKVNY/4A3JFq46CnL1f+ZQ/jKuQUY53DG85Uc+ivRgJqUoWuYp3DjXMLexbN/0NPcxjE+P8Cbr+jNMf/MkdpZ1tvJDQJG+bXlFJq0f5r1kX/7RNKnqeHAaz1n3GA53VeBFmuTEUp+bnd5ZhItSmG/WmZBHxw8OxIRDR8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LOUnWz8f; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LOUnWz8f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27364C4CEF5; Mon, 15 Dec 2025 14:21:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765808497; bh=MTKeMG3Bg3HAsEC7hfWzoaJNW/z6vXP7y9UpwJgb2Xs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LOUnWz8f8B28/CmY93A7rmr4wvY2vxzJ4iJruFcYfnS6A16fTe6GKcuzkZjndkfYO hxR3rFifSqdWt5sLao1yCxtMuU5yLlyangxWzGmQbSiiqA71mBwoKCjc6l8kwvON5P NcNF2Vk2667uFdvGoOQPk5yUk/HJthKAhW+suNlNhmqlMS8bbMIsLVLRWotQOd6L/n 5ky7SnmylKzT9UXD6d1iyUocrJ76/5A4cdMSbkAKaoTYrnIwmRf5L+ck63XXj5Rrcq jp4CXknDK2uAa40bVmejxyFxDWkuHBVH1bLfZAspw3ZvftPNcSVfaa3HUkAYdsxpdg Y/TdBbMQPXALA== From: "Rafael J. Wysocki" To: Ed Tsai , linux-pm@vger.kernel.org Cc: Ulf Hansson , linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, chun-hung.wu@mediatek.com, freddy.shin@mediatek.com, "Rafael J. Wysocki" Subject: [PATCH v1] PM: runtime: Do not clear needs_force_resume with enabled runtime PM Date: Mon, 15 Dec 2025 15:21:34 +0100 Message-ID: <12807571.O9o76ZdvQC@rafael.j.wysocki> Organization: Linux Kernel Development In-Reply-To: <20251215122154.3180001-1-ed.tsai@mediatek.com> References: <20251215122154.3180001-1-ed.tsai@mediatek.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On Monday, December 15, 2025 1:21:42 PM CET ed.tsai@mediatek.com wrote: > From: Ed Tsai >=20 > needs_force_resume is a bitfield member in struct dev_pm_info and must > be accessed under the same lock as its bitfield group. >=20 > A real concurrent write was observed between needs_force_resume and > idle_notification; stacks below: >=20 > write needs_force_resume: > pm_runtime_reinit+0x110/0x360 > really_probe+0xe0/0x464 > __driver_probe_device+0x9c/0x104 > driver_probe_device+0x3c/0x1a8 > __device_attach_driver+0x100/0x17c > bus_for_each_drv+0x10c/0x168 > __device_attach_async_helper+0x7c/0xf4 > async_run_entry_fn+0x4c/0x1b4 > process_scheduled_works+0x1dc/0x498 > worker_thread+0x220/0x320 > kthread+0x150/0x27c > ret_from_fork+0x10/0x20 >=20 > write idle_notification: > rpm_idle+0x464/0x5f8 > __pm_runtime_idle+0x7c/0x170 > scsi_autopm_put_device+0x18/0x28 > scsi_sysfs_add_sdev+0x1a0/0x1d8 > scsi_probe_and_add_lun+0xbd8/0xcd0 > __scsi_add_device+0xb8/0x11c > ufshcd_async_scan+0xb4/0x3a4 > async_run_entry_fn+0x4c/0x1b4 > process_scheduled_works+0x1dc/0x498 > worker_thread+0x220/0x320 > kthread+0x150/0x27c > ret_from_fork+0x10/0x20 >=20 > Fixes: 89d9cec3b1e9 ("PM: runtime: Clear power.needs_force_resume in pm_r= untime_reinit()") > Signed-off-by: Ed Tsai > --- > drivers/base/power/runtime.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) >=20 > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c > index 84676cc24221..3328543b1ed8 100644 > --- a/drivers/base/power/runtime.c > +++ b/drivers/base/power/runtime.c > @@ -1879,11 +1879,22 @@ void pm_runtime_reinit(struct device *dev) > pm_runtime_put(dev->parent); > } > } > + > /* > * Clear power.needs_force_resume in case it has been set by > * pm_runtime_force_suspend() invoked from a driver remove callback. > */ > + if (dev->power.irq_safe) > + spin_lock(&dev->power.lock); > + else > + spin_lock_irq(&dev->power.lock); > + > dev->power.needs_force_resume =3D false; > + > + if (dev->power.irq_safe) > + spin_unlock(&dev->power.lock); > + else > + spin_unlock_irq(&dev->power.lock); > } > =20 > /** >=20 Thanks for the patch, but this happens because the flag is cleared when runtime PM is enabled which shouldn't be necessary, so I'd prefer to make the change below. Reported-by: Ed Tsai Reviewed-by: Ulf Hansson --- From: Rafael J. Wysocki Subject: [PATCH v1] PM: runtime: Do not clear needs_force_resume with enabl= ed runtime PM Commit 89d9cec3b1e9 ("PM: runtime: Clear power.needs_force_resume in pm_runtime_reinit()") added provisional clearing of power.needs_force_resume to pm_runtime_reinit(), but it is done unconditionally which is a mistake because pm_runtime_reinit() may race with driver probing and removal [1]. To address this, notice that power.needs_force_resume should never be set when runtime PM is enabled and so it only needs to be cleared when runtime PM is disabled, and update pm_runtime_init() to only clear that flag when runtime PM is disabled. Fixes: 89d9cec3b1e9 ("PM: runtime: Clear power.needs_force_resume in pm_run= time_reinit()") Reported-by: Ed Tsai Closes: https://lore.kernel.org/linux-pm/20251215122154.3180001-1-ed.tsai@m= ediatek.com/ [1] Signed-off-by: Rafael J. Wysocki --- drivers/base/power/runtime.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1878,16 +1878,18 @@ void pm_runtime_init(struct device *dev) */ void pm_runtime_reinit(struct device *dev) { - if (!pm_runtime_enabled(dev)) { - if (dev->power.runtime_status =3D=3D RPM_ACTIVE) - pm_runtime_set_suspended(dev); - if (dev->power.irq_safe) { - spin_lock_irq(&dev->power.lock); - dev->power.irq_safe =3D 0; - spin_unlock_irq(&dev->power.lock); - if (dev->parent) - pm_runtime_put(dev->parent); - } + if (pm_runtime_enabled(dev)) + return; + + if (dev->power.runtime_status =3D=3D RPM_ACTIVE) + pm_runtime_set_suspended(dev); + + if (dev->power.irq_safe) { + spin_lock_irq(&dev->power.lock); + dev->power.irq_safe =3D 0; + spin_unlock_irq(&dev->power.lock); + if (dev->parent) + pm_runtime_put(dev->parent); } /* * Clear power.needs_force_resume in case it has been set by