linux-kernel - [PATCH 3/6] kexec: clear crashk_res if all its memory has been released

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Message-ID: <20230527123439.772-4-thunder.leizhen@huawei.com>
Date:   Sat, 27 May 2023 20:34:36 +0800
From:   Zhen Lei <thunder.leizhen@...wei.com>
To:     Eric Biederman <ebiederm@...ssion.com>,
        Baoquan He <bhe@...hat.com>, <kexec@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     Zhen Lei <thunder.leizhen@...wei.com>,
        Michael Holzheu <holzheu@...ux.vnet.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Amerigo Wang <amwang@...hat.com>
Subject: [PATCH 3/6] kexec: clear crashk_res if all its memory has been released

If the resource of crashk_res has been released, it is better to clear
crashk_res.start and crashk_res.end. Because 'end = start - 1' is not
reasonable, and in some places the test is based on crashk_res.end, not
resource_size(&crashk_res).

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
 kernel/kexec_core.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index d1ab139dd49035e..bcc86a250ab3bf9 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -1137,15 +1137,18 @@ int crash_shrink_memory(unsigned long new_size)
 	end = start + new_size;
 	crash_free_reserved_phys_range(end, crashk_res.end);
 
-	if (start == end)
-		release_resource(&crashk_res);
-
 	ram_res->start = end;
 	ram_res->end = crashk_res.end;
 	ram_res->flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM;
 	ram_res->name = "System RAM";
 
-	crashk_res.end = end - 1;
+	if (start == end) {
+		release_resource(&crashk_res);
+		crashk_res.start = 0;
+		crashk_res.end = 0;
+	} else {
+		crashk_res.end = end - 1;
+	}
 
 	insert_resource(&iomem_resource, ram_res);
 
-- 
2.25.1