Re: [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs

Adrian Hunter
2021-01-13T14:54:25Z

On 13/01/21 3:57 pm, Can Guo wrote:
> User layer may access sysfs nodes when system PM ops or error handling
> is running, which can cause various problems. Rename eh_sem to host_sem
> and use it to protect PM ops and error handling from user layer intervene.
>
> Acked-by: Avri Altman <avri.altman@wdc.com>
> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
> drivers/scsi/ufs/ufs-sysfs.c | 106 ++++++++++++++++++++++++++++++++++++-------
> drivers/scsi/ufs/ufshcd.c | 42 ++++++++++-------
> drivers/scsi/ufs/ufshcd.h | 10 +++-
> 3 files changed, 125 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
> index 0e14384..7cafffc 100644
> --- a/drivers/scsi/ufs/ufs-sysfs.c
> +++ b/drivers/scsi/ufs/ufs-sysfs.c
> @@ -154,18 +154,29 @@ static ssize_t auto_hibern8_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> u32 ahit;
> + int ret;
> struct ufs_hba *hba = dev_get_drvdata(dev);
>
> if (!ufshcd_is_auto_hibern8_supported(hba))
> return -EOPNOTSUPP;
>
> + down(&hba->host_sem);
> + if (!ufshcd_is_sysfs_allowed(hba)) {

I expect debugfs has the same potential problem, so maybe
ufshcd_is_sysfs_allowed() is not quite the right name.

> + ret = -EBUSY;
> + goto out;
> + }
> +