linux-kernel - [PATCH v1 1/9] powerpc/vdso: Remove BUG_ON() in vdso

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Date:   Tue, 25 Aug 2020 13:53:59 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 1/9] powerpc/vdso: Remove BUG_ON() in vdso_init()

If we are not able to allocate memory for the pagelists, bail out.

There is no reason to crash the machine, just have vdso init fail.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
This series is based on top of the series switching to C VDSO implementation,
but in fact only the last patch depends on that series and is not vital as
it is just afterwork cleanup.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/vdso.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 23208a051af5..88a4a02ed4c4 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -747,20 +747,16 @@ static int __init vdso_init(void)
 	 * Initialize the vDSO images in memory, that is do necessary
 	 * fixups of vDSO symbols, locate trampolines, etc...
 	 */
-	if (vdso_setup()) {
-		printk(KERN_ERR "vDSO setup failure, not enabled !\n");
-		vdso32_pages = 0;
-#ifdef CONFIG_PPC64
-		vdso64_pages = 0;
-#endif
-		return 0;
-	}
+	if (vdso_setup())
+		goto setup_failed;
 
 #ifdef CONFIG_VDSO32
 	/* Make sure pages are in the correct state */
 	vdso32_pagelist = kcalloc(vdso32_pages + 2, sizeof(struct page *),
 				  GFP_KERNEL);
-	BUG_ON(vdso32_pagelist == NULL);
+	if (!vdso32_pagelist)
+		goto alloc_failed;
+
 	for (i = 0; i < vdso32_pages; i++) {
 		struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
 		get_page(pg);
@@ -773,7 +769,9 @@ static int __init vdso_init(void)
 #ifdef CONFIG_PPC64
 	vdso64_pagelist = kcalloc(vdso64_pages + 2, sizeof(struct page *),
 				  GFP_KERNEL);
-	BUG_ON(vdso64_pagelist == NULL);
+	if (!vdso64_pagelist)
+		goto alloc_failed;
+
 	for (i = 0; i < vdso64_pages; i++) {
 		struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
 		get_page(pg);
@@ -789,5 +787,14 @@ static int __init vdso_init(void)
 	vdso_ready = 1;
 
 	return 0;
+
+setup_failed:
+	pr_err("vDSO setup failure, not enabled !\n");
+alloc_failed:
+	vdso32_pages = 0;
+#ifdef CONFIG_PPC64
+	vdso64_pages = 0;
+#endif
+	return 0;
 }
 arch_initcall(vdso_init);
-- 
2.25.0