55c7158d16
Description of Problem: In cyclic mode, makedumpfile recalculates cyclic buffer size as the largest multiple of the largest block size managed by buddy allocator, i.e. 4MB, smaller than the cyclic buffer size in order to enable to process each unit of blocks managed by buddy allocator in each cycle. However, makedumpfile does two wrong things in the recalculations: 1) While updating size of cyclic buffer, makedumpfile doesn't update length of range of cycle in page frame numbers, due to which, if cyclic buffer size is updated, because cyclic buffer size is always reduced during udpate, some buffer overrun can happen on the cyclic buffer. This can cause segmentation violation in the worst case. 2) roundup() is used to calculate bitmap size for maximum block size managed by buddy allocator, here divideup() is correct, due to which, although memory filtering is not affected, cyclic buffer size get too much aligned and less efficient. Fix patches has already been posted and merged in makedumpfile development devel branch. git://git.code.sf.net/p/makedumpfile/code f8c8218856effc43ea01cd9394761cfb8aeaa8df a785fa7dd7a7bd7dcbb017d0bea8848243b0924f Signed-off-by: Baoquan He <bhe@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: WANG Chao <chaowang@redhat.com>
34 lines
1.2 KiB
Diff
34 lines
1.2 KiB
Diff
From a785fa7dd7a7bd7dcbb017d0bea8848243b0924f Mon Sep 17 00:00:00 2001
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Message-Id: <a785fa7dd7a7bd7dcbb017d0bea8848243b0924f.1382423400.git.bhe@redhat.com>
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From: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
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Date: Thu, 12 Sep 2013 08:31:28 +0900
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Subject: [PATCH 1/2] [PATCH] Update pfn_cyclic when the cyclic buffer size is
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corrected.
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When the clearing bit operation for excluding free pages can overrun
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the cyclic buffer, the buffer size is changed with
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check_cyclic_buffer_overrun().
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Then pfn_cyclic should be recalculated.
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Reviewed-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
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Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
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---
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makedumpfile.c | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/makedumpfile-1.5.4/makedumpfile.c b/makedumpfile-1.5.4/makedumpfile.c
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index 09c0d4a..164b3f1 100644
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--- a/makedumpfile-1.5.4/makedumpfile.c
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+++ b/makedumpfile-1.5.4/makedumpfile.c
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@@ -4091,6 +4091,7 @@ check_cyclic_buffer_overrun(void)
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bufsize = info->bufsize_cyclic;
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info->bufsize_cyclic = round(bufsize, max_block_size);
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+ info->pfn_cyclic = info->bufsize_cyclic * BITPERBYTE;
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MSG("cyclic buffer size has been changed: %lu => %lu\n",
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bufsize, info->bufsize_cyclic);
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--
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1.8.3.1
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