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From: Sergey Shtylyov <s.shtylyov@omp.ru>
To: Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@kernel.org>, <dm-devel@redhat.com>
Cc: <linux-kernel@vger.kernel.org>, <lvc-patches@linuxtesting.org>,
	<lvc-patches@linuxtesting.org>
Subject: [PATCH] md: dm-ioctl: drop always-false condition
Date: Tue, 17 Jan 2023 23:59:55 +0300	[thread overview]
Message-ID: <c8c9df45-1d59-3195-7631-51b3a58148ee@omp.ru> (raw)

The expression 'indata[3] > ULONG_MAX' always evaluates to false since
indata[] is declared as an array of *unsigned long* elements and #define
ULONG_MAX represents the max value of that exact type...

Note that gcc seems to be able to detect the dead code here and eliminate
this check anyway...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>

---
This patch is atop of the 'for-next' branch of the device-mapper repo...

 drivers/md/dm-ioctl.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: linux-dm/drivers/md/dm-ioctl.c
===================================================================
--- linux-dm.orig/drivers/md/dm-ioctl.c
+++ linux-dm/drivers/md/dm-ioctl.c
@@ -1073,8 +1073,7 @@ static int dev_set_geometry(struct file
 		goto out;
 	}
 
-	if (indata[0] > 65535 || indata[1] > 255 ||
-	    indata[2] > 255 || indata[3] > ULONG_MAX) {
+	if (indata[0] > 65535 || indata[1] > 255 || indata[2] > 255) {
 		DMERR("Geometry exceeds range limits.");
 		goto out;
 	}

WARNING: multiple messages have this Message-ID (diff)
From: Sergey Shtylyov <s.shtylyov@omp.ru>
To: Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@kernel.org>, <dm-devel@redhat.com>
Cc: lvc-patches@linuxtesting.org, linux-kernel@vger.kernel.org
Subject: [dm-devel] [PATCH] md: dm-ioctl: drop always-false condition
Date: Tue, 17 Jan 2023 23:59:55 +0300	[thread overview]
Message-ID: <c8c9df45-1d59-3195-7631-51b3a58148ee@omp.ru> (raw)

The expression 'indata[3] > ULONG_MAX' always evaluates to false since
indata[] is declared as an array of *unsigned long* elements and #define
ULONG_MAX represents the max value of that exact type...

Note that gcc seems to be able to detect the dead code here and eliminate
this check anyway...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>

---
This patch is atop of the 'for-next' branch of the device-mapper repo...

 drivers/md/dm-ioctl.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: linux-dm/drivers/md/dm-ioctl.c
===================================================================
--- linux-dm.orig/drivers/md/dm-ioctl.c
+++ linux-dm/drivers/md/dm-ioctl.c
@@ -1073,8 +1073,7 @@ static int dev_set_geometry(struct file
 		goto out;
 	}
 
-	if (indata[0] > 65535 || indata[1] > 255 ||
-	    indata[2] > 255 || indata[3] > ULONG_MAX) {
+	if (indata[0] > 65535 || indata[1] > 255 || indata[2] > 255) {
 		DMERR("Geometry exceeds range limits.");
 		goto out;
 	}

--
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https://listman.redhat.com/mailman/listinfo/dm-devel


             reply	other threads:[~2023-01-17 23:15 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-17 20:59 Sergey Shtylyov [this message]
2023-01-17 20:59 ` [dm-devel] [PATCH] md: dm-ioctl: drop always-false condition Sergey Shtylyov
2023-01-18 11:59 ` Mikulas Patocka
2023-01-18 11:59   ` Mikulas Patocka
2023-02-06 20:58   ` Sergey Shtylyov
2023-02-06 20:58     ` Sergey Shtylyov
2023-02-06 21:03     ` Mike Snitzer
2023-02-06 21:03       ` [dm-devel] " Mike Snitzer

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