linux-kernel - [PATCH] kexec_core: Accept unaccepted kexec destination addresses

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Message-ID: <20241021034553.18824-1-yan.y.zhao@intel.com>
Date: Mon, 21 Oct 2024 11:45:53 +0800
From: Yan Zhao <yan.y.zhao@...el.com>
To: ebiederm@...ssion.com
Cc: kexec@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-coco@...ts.linux.dev,
	x86@...nel.org,
	rick.p.edgecombe@...el.com,
	kirill.shutemov@...ux.intel.com,
	Yan Zhao <yan.y.zhao@...el.com>
Subject: [PATCH] kexec_core: Accept unaccepted kexec destination addresses

The kexec destination addresses (incluing those for purgatory, the new
kernel, boot params/cmdline, and initrd) are searched from the free area of
memblock or RAM resources. Since they are not allocated by the currently
running kernel, it is not guaranteed that they are accepted before
relocating the new kernel.

Accept the destination addresses for the new kernel, as the new kernel may
not be able to or may not accept them by itself.

Place the "accept" code immediately after the destination addresses pass
sanity checks, so the code can be shared by both users of the kexec_load
and kexec_file_load system calls.

Cc: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@...el.com>
---
 kernel/kexec_core.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index c0caa14880c3..d97376eafc1a 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -210,6 +210,16 @@ int sanity_check_segment_list(struct kimage *image)
 	}
 #endif

+	/*
+	 * The destination addresses are searched from free memory ranges rather
+	 * than being allocated from the current kernel, so they are not
+	 * guaranteed to be accepted by the current kernel.
+	 * Accept those initial pages for the new kernel since it may not be
+	 * able to accept them by itself.
+	 */
+	for (i = 0; i < nr_segments; i++)
+		accept_memory(image->segment[i].mem, image->segment[i].memsz);
+
 	return 0;
 }

base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b
-- 
2.43.2