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Re: [PATCH v2] x86/microcode: Silence a static checker warning

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Ok,

your initial patch was on the right track but let's simplify the whole
flow. That should not trigger your checker warning anymore:

---
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 59edbe9d4ccb..8f7a9bbad514 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -146,18 +146,18 @@ static bool microcode_matches(struct microcode_header_intel *mc_header,
 	return false;
 }
 
-static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
+static struct ucode_patch *memdup_patch(void *data, unsigned int size)
 {
 	struct ucode_patch *p;
 
 	p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
 	if (!p)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	p->data = kmemdup(data, size, GFP_KERNEL);
 	if (!p->data) {
 		kfree(p);
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 	}
 
 	return p;
@@ -183,8 +183,8 @@ static void save_microcode_patch(void *data, unsigned int size)
 			if (mc_hdr->rev <= mc_saved_hdr->rev)
 				continue;
 
-			p = __alloc_microcode_buf(data, size);
-			if (IS_ERR(p))
+			p = memdup_patch(data, size);
+			if (!p)
 				pr_err("Error allocating buffer %p\n", data);
 			else
 				list_replace(&iter->plist, &p->plist);
@@ -196,24 +196,25 @@ static void save_microcode_patch(void *data, unsigned int size)
 	 * newly found.
 	 */
 	if (!prev_found) {
-		p = __alloc_microcode_buf(data, size);
-		if (IS_ERR(p))
+		p = memdup_patch(data, size);
+		if (!p)
 			pr_err("Error allocating buffer for %p\n", data);
 		else
 			list_add_tail(&p->plist, &microcode_cache);
 	}
 
+	if (!p)
+		return;
+
 	/*
 	 * Save for early loading. On 32-bit, that needs to be a physical
 	 * address as the APs are running from physical addresses, before
 	 * paging has been enabled.
 	 */
-	if (p) {
-		if (IS_ENABLED(CONFIG_X86_32))
-			intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
-		else
-			intel_ucode_patch = p->data;
-	}
+	if (IS_ENABLED(CONFIG_X86_32))
+		intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
+	else
+		intel_ucode_patch = p->data;
 }
 
 static int microcode_sanity_check(void *mc, int print_err)

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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[PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-24 22:20 +0200
  Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-24 22:50 +0200
    Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-24 23:00 +0200
      Re: [PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-24 23:10 +0200
        Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-24 23:20 +0200
          Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-25 11:10 +0200
            Re: [PATCH v2] x86/microcode: Silence a static checker warning Borislav Petkov <bp@alien8.de> - 2017-08-25 11:20 +0200
              [PATCH] x86/microcode/intel: Improve microcode patches saving flow Borislav Petkov <bp@alien8.de> - 2017-08-25 12:10 +0200
                Re: [PATCH] x86/microcode/intel: Improve microcode patches saving  flow walter harms <wharms@bfs.de> - 2017-08-25 12:50 +0200
                Re: [PATCH] x86/microcode/intel: Improve microcode patches saving  flow Borislav Petkov <bp@alien8.de> - 2017-08-25 13:50 +0200
                [tip:x86/microcode] x86/microcode/intel: Improve microcode patches  saving flow tip-bot for Borislav Petkov <tipbot@zytor.com> - 2017-08-29 11:10 +0200
            Re: [PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-25 11:20 +0200
    Re: [PATCH v2] x86/microcode: Silence a static checker warning Dan Carpenter <dan.carpenter@oracle.com> - 2017-08-24 23:00 +0200
    Re: [PATCH v2] x86/microcode: Silence a static checker warning Joe Perches <joe@perches.com> - 2017-08-24 23:10 +0200

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