On Tue, Jan 31, 2023 at 09:46:08PM -0800, Satya Durga Srinivasu Prabhala wrote:
> When multiple clients try to update the recovery flag, it is
> possible that, race condition would lead to undesired results
> as updates to recovery flag isn't protected by any mechanism
> today. To avoid such issues, take remoteproc mutex lock before
> updating recovery flag and release the lock once done.
>
The only query of recovery_disabled that I can see is in
rproc_crash_handler_work(), outside of any lock. So I'm not able to see
the issue you're referring to.
Can you please help me understand better?
Thanks,
Bjorn
> Signed-off-by: Satya Durga Srinivasu Prabhala <quic_satyap@xxxxxxxxxxx>
> ---
> v1 -> v2:
> - addressed comments from Mukesh Ojha
> 1. take & release lock only while updating recovery flag
> 2. update debugfs
>
> drivers/remoteproc/remoteproc_debugfs.c | 4 ++++
> drivers/remoteproc/remoteproc_sysfs.c | 4 ++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
> index b86c1d09c70c..2c44d375024e 100644
> --- a/drivers/remoteproc/remoteproc_debugfs.c
> +++ b/drivers/remoteproc/remoteproc_debugfs.c
> @@ -226,10 +226,14 @@ rproc_recovery_write(struct file *filp, const char __user *user_buf,
>
> if (!strncmp(buf, "enabled", count)) {
> /* change the flag and begin the recovery process if needed */
> + mutex_lock(&rproc->lock);
> rproc->recovery_disabled = false;
> + mutex_unlock(&rproc->lock);
> rproc_trigger_recovery(rproc);
> } else if (!strncmp(buf, "disabled", count)) {
> + mutex_lock(&rproc->lock);
> rproc->recovery_disabled = true;
> + mutex_unlock(&rproc->lock);
> } else if (!strncmp(buf, "recover", count)) {
> /* begin the recovery process without changing the flag */
> rproc_trigger_recovery(rproc);
> diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
> index 8c7ea8922638..628e0de9a132 100644
> --- a/drivers/remoteproc/remoteproc_sysfs.c
> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> @@ -50,10 +50,14 @@ static ssize_t recovery_store(struct device *dev,
>
> if (sysfs_streq(buf, "enabled")) {
> /* change the flag and begin the recovery process if needed */
> + mutex_lock(&rproc->lock);
> rproc->recovery_disabled = false;
> + mutex_unlock(&rproc->lock);
> rproc_trigger_recovery(rproc);
> } else if (sysfs_streq(buf, "disabled")) {
> + mutex_lock(&rproc->lock);
> rproc->recovery_disabled = true;
> + mutex_unlock(&rproc->lock);
> } else if (sysfs_streq(buf, "recover")) {
> /* begin the recovery process without changing the flag */
> rproc_trigger_recovery(rproc);
> --
> 2.38.1
>
