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Groups > linux.kernel > #1255454

[PATCH v4 03/15] scsi: ufs: verify command tag validity

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A race condition appear to exist between request completion when
scsi_done() is called to end the request and set the tag back to
-1 (at blk_queue_end_tag() scsi_end_request), and scsi layer error
handling which aborts the command and reuses it to request sense
data. Sending the request sense is done with tag which was set to -1
and so it is invalid.
Assert command tag passed from scsi layer is valid.

Signed-off-by: Gilad Broner <gbroner@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
 drivers/scsi/ufs/ufshcd.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2d3ebca..8860a57 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -190,6 +190,10 @@ static int ufshcd_config_pwr_mode(struct ufs_hba *hba,
 		struct ufs_pa_layer_attr *desired_pwr_mode);
 static int ufshcd_change_power_mode(struct ufs_hba *hba,
 			     struct ufs_pa_layer_attr *pwr_mode);
+static inline bool ufshcd_valid_tag(struct ufs_hba *hba, int tag)
+{
+	return tag >= 0 && tag < hba->nutrs;
+}
 
 static inline int ufshcd_enable_irq(struct ufs_hba *hba)
 {
@@ -1310,6 +1314,12 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	hba = shost_priv(host);
 
 	tag = cmd->request->tag;
+	if (!ufshcd_valid_tag(hba, tag)) {
+		dev_err(hba->dev,
+			"%s: invalid command tag %d: cmd=0x%p, cmd->request=0x%p",
+			__func__, tag, cmd, cmd->request);
+		BUG();
+	}
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	switch (hba->ufshcd_state) {
@@ -3862,13 +3872,23 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	host = cmd->device->host;
 	hba = shost_priv(host);
 	tag = cmd->request->tag;
+	if (!ufshcd_valid_tag(hba, tag)) {
+		dev_err(hba->dev,
+			"%s: invalid command tag %d: cmd=0x%p, cmd->request=0x%p",
+			__func__, tag, cmd, cmd->request);
+		BUG();
+	}
 
 	ufshcd_hold(hba, false);
+	reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
 	/* If command is already aborted/completed, return SUCCESS */
-	if (!(test_bit(tag, &hba->outstanding_reqs)))
+	if (!(test_bit(tag, &hba->outstanding_reqs))) {
+		dev_err(hba->dev,
+			"%s: cmd at tag %d already completed, outstanding=0x%lx, doorbell=0x%x\n",
+			__func__, tag, hba->outstanding_reqs, reg);
 		goto out;
+	}
 
-	reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
 	if (!(reg & (1 << tag))) {
 		dev_err(hba->dev,
 		"%s: cmd was completed, but without a notifying intr, tag = %d",
-- 
1.8.5.2

-- 
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Thread

[PATCH v4 00/15] Big fixes, retries, handle a race condition Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 08/15] scsi: ufs: add retries to dme_peer get and set attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 04/15] scsi: ufs: clear outstanding_request bit in case query timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 13/15] scsi: ufs: add missing memory barriers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 15/15] scsi: ufs: add wrapper for retrying sending query attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 06/15] scsi: ufs: avoid exception event handler racing with PM callbacks Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 10/15] scsi: ufs: fix error recovery after the hibern8 exit failure Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 03/15] scsi: ufs: verify command tag validity Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 09/15] scsi: ufs: add retries for hibern8 enter Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 14/15] scsi: ufs: commit descriptors before setting the doorbell Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 05/15] scsi: ufs: increase fDeviceInit query response timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 02/15] scsi: ufs: clear fields UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:00 +0100
  [PATCH v4 01/15] scsi: ufs: clear UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:10 +0100
  [PATCH v4 07/15] scsi: ufs: set REQUEST_SENSE command size to 18 bytes Yaniv Gardi <ygardi@codeaurora.org> - 2015-10-25 16:10 +0100

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