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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        "Raghava Aditya Renukunta" <RaghavaAditya.Renukunta@microsemi.com>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.371512497@decadent.org.uk>
Subject: [PATCH 3.16 094/410] scsi: aacraid: Fix udev inquiry race condition
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>

commit f4e8708d3104437fd7716e957f38c265b0c509ef upstream.

When udev requests for a devices inquiry string, it might create multiple
threads causing a race condition on the shared inquiry resource string.

Created a buffer with the string for each thread.

Fixes: 3bc8070fb75b3315 ([SCSI] aacraid: SMC vendor identification)
Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
[bwh: Backported to 3.16:
 - s/sup_adap_info->adapter_type_text/dev->supplement_adapter_info.AdapterTypeText/
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/drivers/scsi/aacraid/aachba.c
+++ b/drivers/scsi/aacraid/aachba.c
@@ -770,8 +770,16 @@ static void setinqstr(struct aac_dev *de
 	memset(str, ' ', sizeof(*str));
 
 	if (dev->supplement_adapter_info.AdapterTypeText[0]) {
-		char * cp = dev->supplement_adapter_info.AdapterTypeText;
 		int c;
+		char *cp;
+		char *cname = kmemdup(dev->supplement_adapter_info.AdapterTypeText,
+				sizeof(dev->supplement_adapter_info.AdapterTypeText),
+								GFP_ATOMIC);
+
+		if (!cname)
+			return;
+
+		cp = cname;
 		if ((cp[0] == 'A') && (cp[1] == 'O') && (cp[2] == 'C'))
 			inqstrcpy("SMC", str->vid);
 		else {
@@ -780,8 +788,7 @@ static void setinqstr(struct aac_dev *de
 				++cp;
 			c = *cp;
 			*cp = '\0';
-			inqstrcpy (dev->supplement_adapter_info.AdapterTypeText,
-				   str->vid);
+			inqstrcpy(cname, str->vid);
 			*cp = c;
 			while (*cp && *cp != ' ')
 				++cp;
@@ -795,8 +802,8 @@ static void setinqstr(struct aac_dev *de
 			cp[sizeof(str->pid)] = '\0';
 		}
 		inqstrcpy (cp, str->pid);
-		if (c)
-			cp[sizeof(str->pid)] = c;
+
+		kfree(cname);
 	} else {
 		struct aac_driver_ident *mp = aac_get_driver_ident(dev->cardtype);