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From:   Pavel Tatashin <pasha.tatashin@soleen.com>
To:     pasha.tatashin@soleen.com, jmorris@namei.org, sashal@kernel.org,
        ebiederm@xmission.com, kexec@lists.infradead.org,
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        mark.rutland@arm.com
Subject: [PATCH v5 03/17] arm64: hibernate: check pgd table allocation
Date:   Mon, 23 Sep 2019 16:34:13 -0400
Message-Id: <20190923203427.294286-4-pasha.tatashin@soleen.com>
In-Reply-To: <20190923203427.294286-1-pasha.tatashin@soleen.com>
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There is a bug in create_safe_exec_page(), when page table is allocated
it is not checked that table is allocated successfully:

But it is dereferenced in: pgd_none(READ_ONCE(*pgdp)).  Check that
allocation was successful.

Fixes: 82869ac57b5d ("arm64: kernel: Add support for hibernate/suspend-to-disk")

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/kernel/hibernate.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index d52f69462c8f..ef46ce66d7e8 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -217,6 +217,11 @@ static int create_safe_exec_page(void *src_start, size_t length,
 	__flush_icache_range(dst, dst + length);
 
 	trans_pgd = allocator(mask);
+	if (!trans_pgd) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
 	pgdp = pgd_offset_raw(trans_pgd, dst_addr);
 	if (pgd_none(READ_ONCE(*pgdp))) {
 		pudp = allocator(mask);
-- 
2.23.0