linux-kernel - [PATCH AUTOSEL 4.18 036/136] powerpc/kdump: Handle crashkernel memory reservation failure

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Message-ID: <20180917030006.245495-36-alexander.levin@microsoft.com>
Date:   Mon, 17 Sep 2018 03:00:34 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Hari Bathini <hbathini@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL 4.18 036/136] powerpc/kdump: Handle crashkernel memory
 reservation failure

From: Hari Bathini <hbathini@...ux.ibm.com>

[ Upstream commit 8950329c4a64c6d3ca0bc34711a1afbd9ce05657 ]

Memory reservation for crashkernel could fail if there are holes around
kdump kernel offset (128M). Fail gracefully in such cases and print an
error message.

Signed-off-by: Hari Bathini <hbathini@...ux.ibm.com>
Tested-by: David Gibson <dgibson@...hat.com>
Reviewed-by: Dave Young <dyoung@...hat.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 arch/powerpc/kernel/machine_kexec.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 936c7e2d421e..b53401334e81 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -188,7 +188,12 @@ void __init reserve_crashkernel(void)
 			(unsigned long)(crashk_res.start >> 20),
 			(unsigned long)(memblock_phys_mem_size() >> 20));
 
-	memblock_reserve(crashk_res.start, crash_size);
+	if (!memblock_is_region_memory(crashk_res.start, crash_size) ||
+	    memblock_reserve(crashk_res.start, crash_size)) {
+		pr_err("Failed to reserve memory for crashkernel!\n");
+		crashk_res.start = crashk_res.end = 0;
+		return;
+	}
 }
 
 int overlaps_crashkernel(unsigned long start, unsigned long size)
-- 
2.17.1