From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (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 55F5E17BB6 for ; Mon, 10 Feb 2025 12:42:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739191372; cv=pass; b=DY1ySk6O208dvUqJR8nKddHQrFrOla/CI+TeSXQ+q0varAWXuZo9aVyZdAdknodxY/blVFA1wAwzLEKV0fJ1ceX4kvEKjxAhUUP939m5GUftdCidI5SrGYXxdhLLAYTf4CBrsqapvxMTbO3BoE0h4qjsGxynBKvwoYplxMdRuSU= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739191372; c=relaxed/simple; bh=CszofFvdDhCnLlEUUIUExSSvk5iBMbeWzjquN8A0IfE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=D5FJnZmbn/c87tcrev+C25/OrxgSoQFnRY4yJ5Dej3VbUk06+6X40BES68AMdB+BrhuNtAqYbf4cEj/SVxW0pB8dGdhfH9MD3igpOz8mFdz+enDejjbJtozjfxEy+wMTAO7SNbd+6Ynb9P0ic9NqrJ3+kuAw+eQZeS5/pwFCf9U= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=adrian.larumbe@collabora.com header.b=ct/bFj+E; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=adrian.larumbe@collabora.com header.b="ct/bFj+E" ARC-Seal: i=1; a=rsa-sha256; t=1739191341; cv=none; d=zohomail.com; s=zohoarc; b=JOHYl2wnY8YOmNPIwyF3HL6wRiLmx6xcDWtT9oxNu6ht4c4nbbeoPr7cDQZxmglNDPuNXngjWQyb8RpE8Jccx8APnPnyQzHwpadHlHADUXjzb5rFiXP74/RLSlAp/GnWFSl4uMA9EAiO9tbvv7HzECN47bgsEOWY9hPiX9Kn9Ks= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1739191341; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=EEk9G+Ux1ply8jWO7j616jY5pUhVWV7F4NM9VKJqnxw=; b=hCajw5erq3RA8BBGeCdb33XT+q7rHwUh/ymKhH7smwrUQms2kNvqgTUoQ+9YqB4bgFEny3iEwDudC91RCUJuiQvRX5MtXqp97jYqqZ+MUVDdvwAdUZwa5hYhBWS4To3A2/HFOEkcvdliy4plAVu+Y+M+CYqmGlBtNcBk+fA9dKM= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=adrian.larumbe@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1739191341; s=zohomail; d=collabora.com; i=adrian.larumbe@collabora.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=EEk9G+Ux1ply8jWO7j616jY5pUhVWV7F4NM9VKJqnxw=; b=ct/bFj+EAJNSN7udS/JNb4eb/UTPMFLyxe+l1nRsE/R+Lt2MHQeN8CPBzT9+lSRZ uTJ18DC0BQUQBXZHuVvJLXUBAp+P07wZzVnanhRurD8cGHot7hz0Cgde6lb8Y+8L2ca OVJUrHf7IJ6ODPcUMIV0RMIGEed7ZGIN+W/HPoVk= Received: by mx.zohomail.com with SMTPS id 173919133701111.912604503558896; Mon, 10 Feb 2025 04:42:17 -0800 (PST) From: =?UTF-8?q?Adri=C3=A1n=20Larumbe?= To: Boris Brezillon , Steven Price , Liviu Dudau , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , =?UTF-8?q?Adri=C3=A1n=20Larumbe?= Cc: kernel@collabora.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] drm/panthor: Replace sleep locks with spinlocks in fdinfo path Date: Mon, 10 Feb 2025 12:41:59 +0000 Message-ID: <20250210124203.124191-1-adrian.larumbe@collabora.com> X-Mailer: git-send-email 2.47.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Panthor's fdinfo handler is routed through the /proc file system, which executes in an atomic context. That means we cannot use mutexes because they might sleep. This bug was uncovered by enabling some of the kernel's mutex-debugging features: CONFIG_DEBUG_RT_MUTEXES=y CONFIG_DEBUG_MUTEXES=y Replace Panthor's group fdinfo data mutex with a guarded spinlock. Signed-off-by: Adrián Larumbe Fixes: e16635d88fa0 ("drm/panthor: add DRM fdinfo support") --- drivers/gpu/drm/panthor/panthor_sched.c | 26 ++++++++++++------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 0b93bf83a9b2..7a267d1efeb6 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -9,6 +9,7 @@ #include #include +#include #include #include #include @@ -631,10 +632,10 @@ struct panthor_group { struct panthor_gpu_usage data; /** - * @lock: Mutex to govern concurrent access from drm file's fdinfo callback - * and job post-completion processing function + * @fdinfo.lock: Spinlock to govern concurrent access from drm file's fdinfo + * callback and job post-completion processing function */ - struct mutex lock; + spinlock_t lock; /** @fdinfo.kbo_sizes: Aggregate size of private kernel BO's held by the group. */ size_t kbo_sizes; @@ -910,8 +911,6 @@ static void group_release_work(struct work_struct *work) release_work); u32 i; - mutex_destroy(&group->fdinfo.lock); - for (i = 0; i < group->queue_count; i++) group_free_queue(group, group->queues[i]); @@ -2861,12 +2860,12 @@ static void update_fdinfo_stats(struct panthor_job *job) struct panthor_job_profiling_data *slots = queue->profiling.slots->kmap; struct panthor_job_profiling_data *data = &slots[job->profiling.slot]; - mutex_lock(&group->fdinfo.lock); - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) - fdinfo->cycles += data->cycles.after - data->cycles.before; - if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) - fdinfo->time += data->time.after - data->time.before; - mutex_unlock(&group->fdinfo.lock); + scoped_guard(spinlock, &group->fdinfo.lock) { + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_CYCLES) + fdinfo->cycles += data->cycles.after - data->cycles.before; + if (job->profiling.mask & PANTHOR_DEVICE_PROFILING_TIMESTAMP) + fdinfo->time += data->time.after - data->time.before; + } } void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) @@ -2880,12 +2879,11 @@ void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile) xa_lock(&gpool->xa); xa_for_each(&gpool->xa, i, group) { - mutex_lock(&group->fdinfo.lock); + guard(spinlock)(&group->fdinfo.lock); pfile->stats.cycles += group->fdinfo.data.cycles; pfile->stats.time += group->fdinfo.data.time; group->fdinfo.data.cycles = 0; group->fdinfo.data.time = 0; - mutex_unlock(&group->fdinfo.lock); } xa_unlock(&gpool->xa); } @@ -3531,7 +3529,7 @@ int panthor_group_create(struct panthor_file *pfile, mutex_unlock(&sched->reset.lock); add_group_kbo_sizes(group->ptdev, group); - mutex_init(&group->fdinfo.lock); + spin_lock_init(&group->fdinfo.lock); return gid; base-commit: 2eca617f12586abff62038db1c14cb3aa60a15aa prerequisite-patch-id: 7e787ce5973b5fc7e9f69f26aa4d7e5ec03d5caa prerequisite-patch-id: 03a619b8c741444b28435850e23d9ec463171c13 prerequisite-patch-id: 290e1053f8bf4a8b80fb037a87cae7e096b5aa96 prerequisite-patch-id: bc49bb8c29905650fb4788acc528bb44013c0240 prerequisite-patch-id: 46cab4c980824c03e5164afc43085fec23e1cba5 -- 2.47.1