From mboxrd@z Thu Jan 1 00:00:00 1970 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 0854B3375D1; Mon, 18 Aug 2025 13:56:57 +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=1755525418; cv=none; b=eumdnSrKegzuIBO1RWwIpVFgPIxmjd0AsPhw9rM7Crnu6ZPKU7DahURki/eX4+CgwJHSef9ksOL4EKuxVV/cdNCropnnEla22hq0txsit+5aWYTRp34bDzURcV91OHQa4Ik+OsPLmD+yFHq3naHsuCMC2/9SRs92oTI9AqOL5/8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755525418; c=relaxed/simple; bh=r851sF/IXQ6nv1XShxIeoNNXQsYjrb/Ebi9qNlT0NEM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EYamvgAXfBIcF+enwrxyMkjeU29dR7/UMslWihkdg119GbF8JUzEXowjhxg2LJq7ZcvETjDO+yRotIBCX8Pz1iI3+htUKo1QTPYjaajk55MrwD3hvc2X+8vcZCyMlLnvttSQc1/r1qQywUxNu4NnZuKhVIqEMzKUGAkRv92pd78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TKwJDTJ/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TKwJDTJ/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15B9FC113D0; Mon, 18 Aug 2025 13:56:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755525417; bh=r851sF/IXQ6nv1XShxIeoNNXQsYjrb/Ebi9qNlT0NEM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TKwJDTJ/IFl9NE3YbGdeG+fCxDGnjlXanIZegEunA6JkYZZ/JcWhMh9HF7k0ih5py a6/bbtKoxXsHEkQvfv9PNJvfst0NeeRTMvtNcYgc862+GPXkukYK831+nko8DIkPLr XVy34+/GTBDv8F0njsAxeGPGGPntwFmpifhVmIgI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tvrtko Ursulin , =?UTF-8?q?Ma=C3=ADra=20Canal?= , Philipp Stanner , Sasha Levin Subject: [PATCH 6.16 256/570] drm/sched: Avoid memory leaks with cancel_job() callback Date: Mon, 18 Aug 2025 14:44:03 +0200 Message-ID: <20250818124515.684210604@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250818124505.781598737@linuxfoundation.org> References: <20250818124505.781598737@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Philipp Stanner [ Upstream commit bf8bbaefaa6ae0a07971ea57b3208df60e8ad0a4 ] Since its inception, the GPU scheduler can leak memory if the driver calls drm_sched_fini() while there are still jobs in flight. The simplest way to solve this in a backwards compatible manner is by adding a new callback, drm_sched_backend_ops.cancel_job(), which instructs the driver to signal the hardware fence associated with the job. Afterwards, the scheduler can safely use the established free_job() callback for freeing the job. Implement the new backend_ops callback cancel_job(). Suggested-by: Tvrtko Ursulin Link: https://lore.kernel.org/dri-devel/20250418113211.69956-1-tvrtko.ursulin@igalia.com/ Reviewed-by: Maíra Canal Acked-by: Tvrtko Ursulin Signed-off-by: Philipp Stanner Link: https://lore.kernel.org/r/20250710125412.128476-4-phasta@kernel.org Signed-off-by: Sasha Levin --- drivers/gpu/drm/scheduler/sched_main.c | 34 ++++++++++++++++---------- include/drm/gpu_scheduler.h | 18 ++++++++++++++ 2 files changed, 39 insertions(+), 13 deletions(-) diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 829579c41c6b..3ac5e6acce04 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -1348,6 +1348,18 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_ } EXPORT_SYMBOL(drm_sched_init); +static void drm_sched_cancel_remaining_jobs(struct drm_gpu_scheduler *sched) +{ + struct drm_sched_job *job, *tmp; + + /* All other accessors are stopped. No locking necessary. */ + list_for_each_entry_safe_reverse(job, tmp, &sched->pending_list, list) { + sched->ops->cancel_job(job); + list_del(&job->list); + sched->ops->free_job(job); + } +} + /** * drm_sched_fini - Destroy a gpu scheduler * @@ -1355,19 +1367,11 @@ EXPORT_SYMBOL(drm_sched_init); * * Tears down and cleans up the scheduler. * - * This stops submission of new jobs to the hardware through - * drm_sched_backend_ops.run_job(). Consequently, drm_sched_backend_ops.free_job() - * will not be called for all jobs still in drm_gpu_scheduler.pending_list. - * There is no solution for this currently. Thus, it is up to the driver to make - * sure that: - * - * a) drm_sched_fini() is only called after for all submitted jobs - * drm_sched_backend_ops.free_job() has been called or that - * b) the jobs for which drm_sched_backend_ops.free_job() has not been called - * after drm_sched_fini() ran are freed manually. - * - * FIXME: Take care of the above problem and prevent this function from leaking - * the jobs in drm_gpu_scheduler.pending_list under any circumstances. + * This stops submission of new jobs to the hardware through &struct + * drm_sched_backend_ops.run_job. If &struct drm_sched_backend_ops.cancel_job + * is implemented, all jobs will be canceled through it and afterwards cleaned + * up through &struct drm_sched_backend_ops.free_job. If cancel_job is not + * implemented, memory could leak. */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { @@ -1397,6 +1401,10 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched) /* Confirm no work left behind accessing device structures */ cancel_delayed_work_sync(&sched->work_tdr); + /* Avoid memory leaks if supported by the driver. */ + if (sched->ops->cancel_job) + drm_sched_cancel_remaining_jobs(sched); + if (sched->own_submit_wq) destroy_workqueue(sched->submit_wq); sched->ready = false; diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h index 1a7e377d4cbb..1eed74c7f2f7 100644 --- a/include/drm/gpu_scheduler.h +++ b/include/drm/gpu_scheduler.h @@ -508,6 +508,24 @@ struct drm_sched_backend_ops { * and it's time to clean it up. */ void (*free_job)(struct drm_sched_job *sched_job); + + /** + * @cancel_job: Used by the scheduler to guarantee remaining jobs' fences + * get signaled in drm_sched_fini(). + * + * Used by the scheduler to cancel all jobs that have not been executed + * with &struct drm_sched_backend_ops.run_job by the time + * drm_sched_fini() gets invoked. + * + * Drivers need to signal the passed job's hardware fence with an + * appropriate error code (e.g., -ECANCELED) in this callback. They + * must not free the job. + * + * The scheduler will only call this callback once it stopped calling + * all other callbacks forever, with the exception of &struct + * drm_sched_backend_ops.free_job. + */ + void (*cancel_job)(struct drm_sched_job *sched_job); }; /** -- 2.39.5