[BUG] makedumpfile v1.5.5

[Jingbai Ma]

Hi Daisuke,

I found a problem with the latest makedumpfile v1.5.5.
I have narrowed down the bug to your patch set:

72d9d063 [PATCH v2 1/2] Use memset() to improve the 1st bitmap 
initialization performance.

363d53fc [PATCH v2 2/2] Write out a whole part of the 1st bitmap before 
entering cyclic process.

After reversed this patch set out, this problem was gone.
Could you check this problem?

I got a segmentation fault during dump kernel. I have copied the vmcore 
to my system to debug it.

makedumpfile -l --message-level 23 -d 31 -f /vmcores/vmcore /dev/null
cyclic buffer size has been changed: 1060863 => 1060736
Excluding unnecessary pages        : [100.0 %] |STEP [Excluding 
unnecessary pages] : 0.280002 seconds
Excluding unnecessary pages        : [100.0 %] \STEP [Excluding 
unnecessary pages] : 0.000194 seconds
Excluding unnecessary pages        : [100.0 %] -STEP [Excluding 
unnecessary pages] : 0.276371 seconds
Excluding unnecessary pages        : [100.0 %] /STEP [Excluding 
unnecessary pages] : 0.000205 seconds
Excluding unnecessary pages        : [100.0 %] \STEP [Excluding 
unnecessary pages] : 0.279320 seconds
Segmentation fault (core dumped)

gdb --args ./makedumpfile -l --message-level 23 -d 31 -f /vmcores/vmcore 
/dev/null

(gdb) run
Starting program: /home/majingb/work/source/makedumpfile/makedumpfile -l 
--message-level 23 -d 31 -f /vmcores/vmcore /dev/null
[Thread debugging using libthread_db enabled]
cyclic buffer size has been changed: 1060863 => 1060736
Excluding unnecessary pages        : [100.0 %] |STEP [Excluding 
unnecessary pages] : 0.306783 seconds
Excluding unnecessary pages        : [100.0 %] \STEP [Excluding 
unnecessary pages] : 0.000197 seconds
Excluding unnecessary pages        : [100.0 %] /STEP [Excluding 
unnecessary pages] : 0.274979 seconds
Excluding unnecessary pages        : [100.0 %] |STEP [Excluding 
unnecessary pages] : 0.000177 seconds
Excluding unnecessary pages        : [100.0 %] \STEP [Excluding 
unnecessary pages] : 0.274816 seconds
Copying data                       : [  7.0 %] -
Program received signal SIGSEGV, Segmentation fault.
__memset_sse2 () at ../sysdeps/x86_64/memset.S:65
65		movswq (%rcx,%r8,2),%rcx
(gdb) bt
#0  __memset_sse2 () at ../sysdeps/x86_64/memset.S:65
#1  0x000000000042ea73 in readpage_elf (type_addr=1, addr=3881992192, 
bufptr=0x7fffffffbc90, size=4096) at makedumpfile.c:402
#2  readmem (type_addr=1, addr=3881992192, bufptr=0x7fffffffbc90, 
size=4096) at makedumpfile.c:594
#3  0x000000000042fe0f in read_pfn (pfn=<value optimized out>, 
buf=<value optimized out>) at makedumpfile.c:5798
#4  0x0000000000430089 in write_kdump_pages_cyclic 
(cd_header=0x7fffffffde00, cd_page=0x7fffffffddd0, 
pd_zero=0x7fffffffdd50, offset_data=0x7fffffffdd88) at makedumpfile.c:6402
#5  0x0000000000437073 in write_kdump_pages_and_bitmap_cyclic 
(cd_header=0x7fffffffde00, cd_page=0x7fffffffddd0) at makedumpfile.c:6880
#6  0x000000000043827b in writeout_dumpfile () at makedumpfile.c:7835
#7  0x00000000004386a5 in create_dumpfile () at makedumpfile.c:8038
#8  0x000000000043944e in main (argc=<value optimized out>, argv=<value 
optimized out>) at makedumpfile.c:9214

In makedumpfile line 402:
                      memset(bufptr, 0, frac_head);
I have printed out the value of frac_head:
p	frac_head
$2 = 18446744069827559424
It seems something wrong here.

Here is the paddr in this context.
(gdb) p	paddr
$3 = 3881992192

I also have printed out the pt_loads for your reference:
(gdb) p *pt_loads at num_pt_loads
$3 = {{file_offset = 12288, phys_start = 16777216, phys_end = 33579008, 
virt_start = 18446744071578845184, virt_end = 18446744071595646976}, 
{file_offset = 16814080, phys_start = 65536, phys_end = 621568,
     virt_start = 18446612132314284032, virt_end = 
18446612132314840064}, {file_offset = 17371136, phys_start = 1048576, 
phys_end = 637534208, virt_start = 18446612132315267072, virt_end = 
18446612132951752704}, {
     file_offset	= 653856768, phys_start = 905969664, phys_end = 
3881955328, virt_start = 18446612133220188160, virt_end = 
18446612136196173824}, {file_offset = 3629842432, phys_start = 
3882008576, phys_end = 3882012672,
     virt_start = 18446612136196227072, virt_end = 
18446612136196231168}, {file_offset = 3629846528, phys_start = 
4294967296, phys_end = 34762387456, virt_start = 18446612136609185792, 
virt_end = 18446612167076605952}}


-- 
Thanks,
Jingbai Ma