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From:   Oscar Salvador <osalvador@suse.de>
To:     akpm@linux-foundation.org
Cc:     mhocko@suse.com, anshuman.khandual@arm.com,
        william.kucharski@oracle.com, hughd@google.com, jack@suse.cz,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Oscar Salvador <osalvador@suse.de>
Subject: [PATCH v2] mm: Fix __dump_page when mapping->host is not set
Date:   Mon, 18 Mar 2019 08:29:31 +0100
Message-Id: <20190318072931.29094-1-osalvador@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Swap mapping->host is NULL, so let us protect __dump_page() for such cases.

Fixes: 1c6fb1d89e73c ("mm: print more information about mapping in __dump_page")
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
---
 mm/debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/debug.c b/mm/debug.c
index c0b31b6c3877..7759f12a8fbb 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -79,7 +79,7 @@ void __dump_page(struct page *page, const char *reason)
 		pr_warn("ksm ");
 	else if (mapping) {
 		pr_warn("%ps ", mapping->a_ops);
-		if (mapping->host->i_dentry.first) {
+		if (mapping->host && mapping->host->i_dentry.first) {
 			struct dentry *dentry;
 			dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
 			pr_warn("name:\"%pd\" ", dentry);
-- 
2.13.7