Hello Kumagai,
while testing my changes for ELF file reading, I found a regression in
makedumpfile. It now segfaults on me when creating an ELF file. I
bisected the regression to this commit:
commit d18796d090623d18f46c8dc608dcad9960fbbe9b
Author: Atsushi Kumagai <ats-kumagai at wm.jp.nec.com>
Date: Mon May 11 14:25:47 2015 +0900
[PATCH 04/13] Integrate the main logic of writing kdump file.
I run my command as:
makedumpfile -E -d31 vmcore-reloc.elf vmcore-reloc.d31.elf
This is the backtrace:
#0 memset () at ../sysdeps/x86_64/memset.S:80
#1 0x00000000004328b4 in initialize_bitmap (bitmap=0x7fffffffda30) at makedumpfile.c:3389
#2 0x00000000004328f4 in initialize_2nd_bitmap (bitmap=0x7fffffffda30) at makedumpfile.c:3403
#3 0x000000000043765c in exclude_zero_pages () at makedumpfile.c:4778
#4 0x0000000000000000 in ?? ()
And this is the output from valgrind:
==5092== Conditional jump or move depends on uninitialised value(s)
==5092== at 0x4C2F8EC: memset (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5092== by 0x4328B3: initialize_bitmap (makedumpfile.c:3389)
==5092== by 0x4328F3: initialize_2nd_bitmap (makedumpfile.c:3403)
==5092== by 0x43765B: exclude_zero_pages (makedumpfile.c:4778)
==5092== by 0x438F63: create_2nd_bitmap (makedumpfile.c:5277)
==5092== by 0x43B2EE: get_num_dumpable_cyclic (makedumpfile.c:6087)
==5092== by 0x439666: create_dump_bitmap (makedumpfile.c:5417)
==5092== by 0x4440BF: create_dumpfile (makedumpfile.c:8700)
==5092== by 0x4499FD: main (makedumpfile.c:10103)
==5092==
==5092== Use of uninitialised value of size 8
==5092== at 0x4C2F957: memset (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5092== by 0x4328B3: initialize_bitmap (makedumpfile.c:3389)
==5092== by 0x4328F3: initialize_2nd_bitmap (makedumpfile.c:3403)
==5092== by 0x43765B: exclude_zero_pages (makedumpfile.c:4778)
==5092== by 0x438F63: create_2nd_bitmap (makedumpfile.c:5277)
==5092== by 0x43B2EE: get_num_dumpable_cyclic (makedumpfile.c:6087)
==5092== by 0x439666: create_dump_bitmap (makedumpfile.c:5417)
==5092== by 0x4440BF: create_dumpfile (makedumpfile.c:8700)
==5092== by 0x4499FD: main (makedumpfile.c:10103)
==5092==
==5092== Conditional jump or move depends on uninitialised value(s)
==5092== at 0x4C2F95D: memset (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5092== by 0x4328B3: initialize_bitmap (makedumpfile.c:3389)
==5092== by 0x4328F3: initialize_2nd_bitmap (makedumpfile.c:3403)
==5092== by 0x43765B: exclude_zero_pages (makedumpfile.c:4778)
==5092== by 0x438F63: create_2nd_bitmap (makedumpfile.c:5277)
==5092== by 0xFFEFFFA5F: ???
==5092== by 0xFFEFFFA5F: ???
==5092== by 0xFFEFFFA9F: ???
==5092== by 0x43B2EE: get_num_dumpable_cyclic (makedumpfile.c:6087)
==5092==
==5092== Invalid write of size 8
==5092== at 0x4C2F957: memset (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==5092== by 0x4328B3: initialize_bitmap (makedumpfile.c:3389)
==5092== by 0x4328F3: initialize_2nd_bitmap (makedumpfile.c:3403)
==5092== by 0x43765B: exclude_zero_pages (makedumpfile.c:4778)
==5092== Address 0xfff001000 is not stack'd, malloc'd or (recently) free'd
I think the bitmap is not initialized properly, but I have no time now
to research further. Is the above information sufficient, or do you
need more info from me?
Regards,
Petr Tesarik
