[PATCH 4/6] ufs: Fix a race condition in the tracing code

Bart Van Assche
2019-12-24T22:03:03Z

Starting execution of a command before tracing a command may cause the
completion handler to free data while it is being traced. Fix this race
by tracing a command before it is submitted.

Cc: Bean Huo <beanhuo@micron.com>
Cc: Can Guo <cang@codeaurora.org>
Cc: Avri Altman <avri.altman@wdc.com>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/scsi/ufs/ufshcd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 80b028ba39e9..4d9bb1932b39 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1875,12 +1875,12 @@ void ufshcd_send_command(struct ufs_hba *hba, unsigned int task_tag)
{
hba->lrb[task_tag].issue_time_stamp = ktime_get();
hba->lrb[task_tag].compl_time_stamp = ktime_set(0, 0);
+ ufshcd_add_command_trace(hba, task_tag, "send");
ufshcd_clk_scaling_start_busy(hba);
__set_bit(task_tag, &hba->outstanding_reqs);
ufshcd_writel(hba, 1 << task_tag, REG_UTP_TRANSFER_REQ_DOOR_BELL);
/* Make sure that doorbell is committed immediately */
wmb();
- ufshcd_add_command_trace(hba, task_tag, "send");
}

/**