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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH v2] x86/microcode: Silence a static checker warning
Date: Thu, 24 Aug 2017 20:15:57 +0000	[thread overview]
Message-ID: <20170824201557.ev4ebslf6sg6xmne@mwanda> (raw)
In-Reply-To: <20170822211335.r7wcfcisdlq2xwgz@pd.tnic>

The code here prints an error if "p" is an error pointer but it still
dereferences it at the end of the function when it does:

	intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);

We can just return early instead.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: return early instead checking for IS_ERR_OR_NULL() at the end.

We have to keep the final check whether "p" is NULL to handle the
situation were we set "prev_found = true;" but then hit the continue
statement instead of allocating "p".

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 59edbe9d4ccb..aab900ddea6a 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -184,10 +184,11 @@ static void save_microcode_patch(void *data, unsigned int size)
 				continue;
 
 			p = __alloc_microcode_buf(data, size);
-			if (IS_ERR(p))
+			if (IS_ERR(p)) {
 				pr_err("Error allocating buffer %p\n", data);
-			else
-				list_replace(&iter->plist, &p->plist);
+				return;
+			}
+			list_replace(&iter->plist, &p->plist);
 		}
 	}
 
@@ -197,10 +198,11 @@ static void save_microcode_patch(void *data, unsigned int size)
 	 */
 	if (!prev_found) {
 		p = __alloc_microcode_buf(data, size);
-		if (IS_ERR(p))
+		if (IS_ERR(p)) {
 			pr_err("Error allocating buffer for %p\n", data);
-		else
-			list_add_tail(&p->plist, &microcode_cache);
+			return;
+		}
+		list_add_tail(&p->plist, &microcode_cache);
 	}
 
 	/*

  reply	other threads:[~2017-08-24 20:15 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-22 20:44 [PATCH] x86/microcode/intel: Silence a static checker warning Dan Carpenter
2017-08-22 21:13 ` Borislav Petkov
2017-08-24 20:15   ` Dan Carpenter [this message]
2017-08-24 20:47     ` [PATCH v2] x86/microcode: " Borislav Petkov
2017-08-24 20:55       ` Dan Carpenter
2017-08-24 20:58         ` Borislav Petkov
2017-08-24 21:08           ` Dan Carpenter
2017-08-24 21:12             ` Borislav Petkov
2017-08-25  9:06               ` Borislav Petkov
2017-08-25  9:12                 ` Dan Carpenter
2017-08-25  9:14                   ` Borislav Petkov
2017-08-25 10:04                     ` [PATCH] x86/microcode/intel: Improve microcode patches saving flow Borislav Petkov
2017-08-25 10:40                       ` walter harms
2017-08-25 11:41                         ` Borislav Petkov
2017-08-24 21:02       ` [PATCH v2] x86/microcode: Silence a static checker warning Joe Perches

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