Re: [PATCH v4 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs
From: Adrian Hunter <adrian.hunter@intel.com>
Date: 2021-01-13 14:54:25
Also in:
linux-mediatek, linux-scsi, lkml
On 13/01/21 3:57 pm, Can Guo wrote:
quoted hunk ↗ jump to hunk
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 <redacted> Signed-off-by: Can Guo <redacted> --- 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; + } +
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