linux-kernel - [PATCH V2 1/2] kexec: Make a pair of map/unmap reserved pages in error path

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Date:	Tue,  1 Mar 2016 16:02:28 +0800
From:	Minfei Huang <mnfhuang@...il.com>
To:	ebiederm@...ssion.com, akpm@...ux-foundation.org
Cc:	kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
	mhuang@...hat.com, Minfei Huang <mnfhuang@...il.com>
Subject: [PATCH V2 1/2] kexec: Make a pair of map/unmap reserved pages in error path

For some arch, kexec shall map the reserved pages, then use them, when
we try to start the kdump service.

kexec may return directly, without unmaping the reserved pages, if it
fails during starting service. To fix it, we make a pair of map/unmap
reserved pages both in generic path and error path.

Signed-off-by: Minfei Huang <mnfhuang@...il.com>
---
 kernel/kexec.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/kexec.c b/kernel/kexec.c
index ee70aef..5cd60c4 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -169,6 +169,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 	dest_image = &kexec_image;
 	if (flags & KEXEC_ON_CRASH)
 		dest_image = &kexec_crash_image;
+
 	if (nr_segments > 0) {
 		unsigned long i;
 
@@ -190,22 +191,25 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 						   segments, flags);
 		}
 		if (result)
-			goto out;
+			goto unmap_page;
 
 		if (flags & KEXEC_PRESERVE_CONTEXT)
 			image->preserve_context = 1;
 		result = machine_kexec_prepare(image);
 		if (result)
-			goto out;
+			goto unmap_page;
 
 		for (i = 0; i < nr_segments; i++) {
 			result = kimage_load_segment(image, &image->segment[i]);
 			if (result)
-				goto out;
+				goto unmap_page;
 		}
 		kimage_terminate(image);
+unmap_page:
 		if (flags & KEXEC_ON_CRASH)
 			crash_unmap_reserved_pages();
+		if (result)
+			goto out;
 	}
 	/* Install the new kernel, and  Uninstall the old */
 	image = xchg(dest_image, image);
-- 
1.9.1