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From: Colin King <colin.king@canonical.com>
To: James Smart <james.smart@broadcom.com>,
	Dick Kennedy <dick.kennedy@broadcom.com>,
	"James E . J . Bottomley" <jejb@linux.ibm.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] scsi: lpfc: fix less than zero comparison on unsigned int computation
Date: Mon,  6 Jul 2020 14:08:20 +0100	[thread overview]
Message-ID: <20200706130820.487271-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The expressions start_idx - dbg_cnt is evaluated using unsigned int
arthithmetic (since these variables are unsigned ints) and hence can
never be less than zero, so the less than comparison is never true.
Re-write the expression to check for start_idx being less than dbg_cnt.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 372c187b8a70 ("scsi: lpfc: Add an internal trace log buffer")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/scsi/lpfc/lpfc_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 7285b0114837..ce5afe7b11d0 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -14152,7 +14152,7 @@ void lpfc_dmp_dbg(struct lpfc_hba *phba)
 		if ((start_idx + dbg_cnt) > (DBG_LOG_SZ - 1)) {
 			temp_idx = (start_idx + dbg_cnt) % DBG_LOG_SZ;
 		} else {
-			if ((start_idx - dbg_cnt) < 0) {
+			if (start_idx < dbg_cnt) {
 				start_idx = DBG_LOG_SZ - (dbg_cnt - start_idx);
 				temp_idx = 0;
 			} else {
-- 
2.27.0


WARNING: multiple messages have this Message-ID (diff)
From: Colin King <colin.king@canonical.com>
To: James Smart <james.smart@broadcom.com>,
	Dick Kennedy <dick.kennedy@broadcom.com>,
	"James E . J . Bottomley" <jejb@linux.ibm.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] scsi: lpfc: fix less than zero comparison on unsigned int computation
Date: Mon, 06 Jul 2020 13:08:20 +0000	[thread overview]
Message-ID: <20200706130820.487271-1-colin.king@canonical.com> (raw)

From: Colin Ian King <colin.king@canonical.com>

The expressions start_idx - dbg_cnt is evaluated using unsigned int
arthithmetic (since these variables are unsigned ints) and hence can
never be less than zero, so the less than comparison is never true.
Re-write the expression to check for start_idx being less than dbg_cnt.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 372c187b8a70 ("scsi: lpfc: Add an internal trace log buffer")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/scsi/lpfc/lpfc_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 7285b0114837..ce5afe7b11d0 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -14152,7 +14152,7 @@ void lpfc_dmp_dbg(struct lpfc_hba *phba)
 		if ((start_idx + dbg_cnt) > (DBG_LOG_SZ - 1)) {
 			temp_idx = (start_idx + dbg_cnt) % DBG_LOG_SZ;
 		} else {
-			if ((start_idx - dbg_cnt) < 0) {
+			if (start_idx < dbg_cnt) {
 				start_idx = DBG_LOG_SZ - (dbg_cnt - start_idx);
 				temp_idx = 0;
 			} else {
-- 
2.27.0

             reply	other threads:[~2020-07-06 13:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-06 13:08 Colin King [this message]
2020-07-06 13:08 ` [PATCH][next] scsi: lpfc: fix less than zero comparison on unsigned int computation Colin King
2020-07-06 14:48 ` James Smart
2020-07-06 14:48   ` James Smart

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