[PATCH AUTOSEL 5.4 093/330] scsi: ufs: Fix a race condition in the tracing code

Sasha Levin
2020-09-18T03:09:29Z

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit eacf36f5bebde5089dddb3d5bfcbeab530b01f8a ]

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>
Link: https://lore.kernel.org/r/20191224220248.30138-5-bvanassche@acm.org
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.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 020a93a40a982..d538b3d4f74a5 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1888,12 +1888,12 @@ 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");
}

/**
--
2.25.1