| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAJ9a7VgJNLJK2oa9Us9bFAEiEmi8_u+NJ1zNrnd5WhhHgxhPxA@mail.gmail.com>
Date: Thu, 19 Dec 2024 12:23:55 +0000
From: Mike Leach <mike.leach@...aro.org>
To: Yeoreum Yun <yeoreum.yun@....com>
Cc: suzuki.poulose@....com, james.clark@...aro.org,
alexander.shishkin@...ux.intel.com, bigeasy@...utronix.de,
clrkwllms@...nel.org, rostedt@...dmis.org, coresight@...ts.linaro.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-rt-devel@...ts.linux.dev
Subject: Re: [PATCH v3 1/9] coresight: change coresight_device lock type to raw_spinlock_t
On Mon, 16 Dec 2024 at 11:50, Yeoreum Yun <yeoreum.yun@....com> wrote:
>
> coresight_device->cscfg_csdev_lock can be held during __schedule()
> by perf_event_task_sched_out()/in().
>
> Since coresight->cscfg_csdev_lock type is spinlock_t and
> perf_event_task_sched_out()/in() is called after acquiring rq_lock,
> which is raw_spinlock_t (an unsleepable lock),
> this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.
>
> To address this, change type of coresight_device->cscfg_csdev_lock
> from spinlock_t to raw_spinlock_t.
>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>
> ---
> .../hwtracing/coresight/coresight-syscfg.c | 26 +++++++++----------
> include/linux/coresight.h | 2 +-
> 2 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> index 11138a9762b0..a70c1454b410 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> @@ -89,9 +89,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
> }
> /* if matched features, add config to device.*/
> if (config_csdev) {
> - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> list_add(&config_csdev->node, &csdev->config_csdev_list);
> - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> }
>
> return 0;
> @@ -194,9 +194,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
>
> /* add to internal csdev feature list & initialise using reset call */
> cscfg_reset_feat(feat_csdev);
> - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> list_add(&feat_csdev->node, &csdev->feature_csdev_list);
> - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
>
> return 0;
> }
> @@ -765,7 +765,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev,
>
> INIT_LIST_HEAD(&csdev->feature_csdev_list);
> INIT_LIST_HEAD(&csdev->config_csdev_list);
> - spin_lock_init(&csdev->cscfg_csdev_lock);
> + raw_spin_lock_init(&csdev->cscfg_csdev_lock);
>
> return 0;
> }
> @@ -855,7 +855,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
> struct cscfg_feature_csdev *feat_csdev;
> unsigned long flags;
>
> - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> if (list_empty(&csdev->feature_csdev_list))
> goto unlock_exit;
>
> @@ -863,7 +863,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
> cscfg_reset_feat(feat_csdev);
>
> unlock_exit:
> - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> }
> EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
>
> @@ -1059,7 +1059,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
> * Look for matching configuration - set the active configuration
> * context if found.
> */
> - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
> config_desc = config_csdev_item->config_desc;
> if ((atomic_read(&config_desc->active_cnt)) &&
> @@ -1069,7 +1069,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
> break;
> }
> }
> - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
>
> /*
> * If found, attempt to enable
> @@ -1090,12 +1090,12 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
> *
> * Set enabled if OK, err if not.
> */
> - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> if (csdev->active_cscfg_ctxt)
> config_csdev_active->enabled = true;
> else
> err = -EBUSY;
> - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> }
> }
> return err;
> @@ -1124,7 +1124,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
> * If it was not enabled, we have no work to do, otherwise mark as disabled.
> * Clear the active config pointer.
> */
> - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
> if (config_csdev) {
> if (!config_csdev->enabled)
> @@ -1133,7 +1133,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
> config_csdev->enabled = false;
> }
> csdev->active_cscfg_ctxt = NULL;
> - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
>
> /* true if there was an enabled active config */
> if (config_csdev)
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index c13342594278..924b58c343b3 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -296,7 +296,7 @@ struct coresight_device {
> /* system configuration and feature lists */
> struct list_head feature_csdev_list;
> struct list_head config_csdev_list;
> - spinlock_t cscfg_csdev_lock;
> + raw_spinlock_t cscfg_csdev_lock;
> void *active_cscfg_ctxt;
> };
>
> --
> LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
>
Reviewed-by: Mike Leach <mike.leach@...aro.org>
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
Powered by blists - more mailing lists