121 lines
4.4 KiB
Diff
121 lines
4.4 KiB
Diff
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From e23dc0a1aa5fa7a4429f72ff1c2fe87a87291065 Mon Sep 17 00:00:00 2001
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From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
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Date: Tue, 17 Sep 2013 15:29:38 +0900
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Subject: [PATCH] [PATCH 2/2] cache: Reuse entry in pending list.
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Currently, sadump_virt_phys_base() fails to calculate phys_base as
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below:
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$ /pub/repos/makedumpfile/makedumpfile -f -p -d 31 -x /pub3/vmcores/comparevmcore_data/vmlinux-2.6.18-363.el5 /pub3/vmcores/comparevmcore_data/vmcore-2.6.18-363.el5-sadump /pub3/vmcores/comparevmcore_data/vmcore-pd31
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Switched running mode from cyclic to non-cyclic,
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because the cyclic mode doesn't support sadump format.
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readmem: type_addr: 1, addr:296020, size:13
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readmem: type_addr: 1, addr:ffffffffff296020, size:13
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readmem: type_addr: 1, addr:ffffffffff396020, size:13
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readmem: type_addr: 1, addr:ffffffffff496020, size:13
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readmem: type_addr: 1, addr:ffffffffff596020, size:13
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readmem: type_addr: 1, addr:ffffffffff696020, size:13
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readmem: type_addr: 1, addr:ffffffffff796020, size:13
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readmem: type_addr: 1, addr:ffffffffff896020, size:13
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readmem: type_addr: 1, addr:ffffffffff996020, size:13
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readmem: type_addr: 1, addr:ffffffffffa96020, size:13
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readmem: type_addr: 1, addr:ffffffffffb96020, size:13
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readmem: type_addr: 1, addr:ffffffffffc96020, size:13
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readmem: type_addr: 1, addr:ffffffffffd96020, size:13
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readmem: type_addr: 1, addr:ffffffffffe96020, size:13
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readmem: type_addr: 1, addr:fffffffffff96020, size:13
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readmem: type_addr: 1, addr:96020, size:13
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readmem: type_addr: 1, addr:196020, size:13
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readmem: type_addr: 1, addr:296020, size:13
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readmem: type_addr: 1, addr:396020, size:13
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readmem: type_addr: 1, addr:496020, size:13
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readmem: type_addr: 1, addr:596020, size:13
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readmem: type_addr: 1, addr:696020, size:13
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readmem: type_addr: 1, addr:796020, size:13
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readmem: type_addr: 1, addr:896020, size:13
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readmem: type_addr: 1, addr:996020, size:13
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readmem: type_addr: 1, addr:a96020, size:13
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readmem: type_addr: 1, addr:b96020, size:13
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readmem: type_addr: 1, addr:c96020, size:13
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readmem: type_addr: 1, addr:d96020, size:13
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readmem: type_addr: 1, addr:e96020, size:13
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readmem: type_addr: 1, addr:f96020, size:13
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readmem: type_addr: 1, addr:1096020, size:13
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readmem: type_addr: 1, addr:1196020, size:13
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readmem: type_addr: 1, addr:1296020, size:13
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readmem: type_addr: 0, addr:ffffffff8045e260, size:32
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cpu_online_mask_init: Can't read cpu_online_mask memory.
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makedumpfile Failed.
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By git bisect, I found this bug is caused by the following commit:
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commit 0aff0e5174d0708bf1bfb039ab863e1fea8a1029
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Author: Petr Tesarik <ptesarik@suse.cz>
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Date: Wed Oct 31 16:12:47 2012 +0900
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[PATCH] keep dumpfile pages in a cache.
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Then, I found this bug happens in the following senario.
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If one of the readpage_xxx() methods fails reading 8 pages in a row, 8
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entries in pool are fully contained in pending list. Then,
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cache_alloc() returns NULL and this continues forever in the
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execution. In other words, there's assumption in cache_alloc() that if
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pool is fully used, they are fully in used list, not in pending list
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at all. However, the buggy path here breaks the assumption. This patch
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changes cache_alloc() so that it first tries to reuse enty in pending
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list if exists.
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In fact, I found this bug in ad-hoc phys_base calculation performed in
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sadump_virt_phys_base(). However, I fixed cache side since this bug
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can occur in general on every vmcore format. Crash dump can contain
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broken data in any part of vmcore and so requested physical address to
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read can be broken likewise.
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Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
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---
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cache.c | 25 +++++++++++++------------
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1 file changed, 13 insertions(+), 12 deletions(-)
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diff --git a/makedumpfile-1.5.4/cache.c b/makedumpfile-1.5.4/cache.c
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index dad8d80..0dd957c 100644
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--- a/makedumpfile-1.5.4/cache.c
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+++ b/makedumpfile-1.5.4/cache.c
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@@ -103,19 +103,20 @@ cache_alloc(unsigned long long paddr)
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{
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struct cache_entry *entry = NULL;
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- if (avail)
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+ if (avail) {
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entry = &pool[--avail];
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-
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- if (!entry) {
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- if (used.tail) {
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- entry = used.tail;
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- remove_entry(&used, entry);
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- } else
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- return NULL;
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- }
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-
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- entry->paddr = paddr;
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- add_entry(&pending, entry);
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+ entry->paddr = paddr;
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+ add_entry(&pending, entry);
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+ } else if (pending.tail) {
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+ entry = pending.tail;
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+ entry->paddr = paddr;
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+ } else if (used.tail) {
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+ entry = used.tail;
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+ remove_entry(&used, entry);
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+ entry->paddr = paddr;
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+ add_entry(&pending, entry);
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+ } else
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+ return NULL;
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return entry->bufptr;
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}
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--
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1.8.3.1
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