Hm, this fix means that the vmlinux symbol table and vmcoreinfo have different values for mem_section. That seems... odd. I had to patch makedumpfile to fix the case of an explicit vmlinux being passed on the command line (which I realized I don't need to do, but it should still work):
Looks good to me, I'll merge this into makedumpfile-1.6.4.
Thanks, Atsushi Kumagai
From 542a11a8f28b0f0a989abc3adff89da22f44c719 Mon Sep 17 00:00:00 2001 Message-Id: 542a11a8f28b0f0a989abc3adff89da22f44c719.1515995400.git.osandov@fb.com From: Omar Sandoval osandov@fb.com Date: Sun, 14 Jan 2018 17:10:30 -0800 Subject: [PATCH] Fix SPARSEMEM_EXTREME support on Linux v4.15 when passing vmlinux
Since kernel commit 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y"), mem_section is a dynamically allocated array of pointers to mem_section instead of a static one (i.e., struct mem_section ** instead of struct mem_section * []). This adds an extra layer of indirection that breaks makedumpfile, which will end up with a bunch of bogus mem_maps.
Since kernel commit a0b1280368d1 ("kdump: write correct address of mem_section into vmcoreinfo"), the mem_section symbol in vmcoreinfo contains the address of the actual struct mem_section * array instead of the address of the pointer in .bss, which gets rid of the extra indirection. However, makedumpfile still uses the debugging symbol from the vmlinux image. Fix this by allowing symbols from the vmcore to override symbols from the vmlinux image. As the comment in initial() says, "vmcoreinfo in /proc/vmcore is more reliable than -x/-i option".
Signed-off-by: Omar Sandoval osandov@fb.com
makedumpfile.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/makedumpfile.h b/makedumpfile.h index 57cf4d9..d68c798 100644 --- a/makedumpfile.h +++ b/makedumpfile.h @@ -274,8 +274,10 @@ do { \ } while (0) #define READ_SYMBOL(str_symbol, symbol) \ do { \
- if (SYMBOL(symbol) == NOT_FOUND_SYMBOL) { \
SYMBOL(symbol) = read_vmcoreinfo_symbol(STR_SYMBOL(str_symbol)); \
- unsigned long _tmp_symbol; \
- _tmp_symbol = read_vmcoreinfo_symbol(STR_SYMBOL(str_symbol)); \
- if (_tmp_symbol != NOT_FOUND_SYMBOL) { \
SYMBOL(symbol) = _tmp_symbol; \-- 2.9.5
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