[PATCH] makedumpfile: bugfix: fix a div-by-zero problem

[Atsushi Kumagai]

>In makedumpfile.c, we want the progress printed 10000 times.
>It is tested by:
>
>(num_dumped % per) == 0
>
>where per is num_dumpable / 10000.
>
>However, if num_dumpable less than 10000, num_dumped % per causes a
>divide-by-zero problem, triggers a SIGFPE.
>
>This patch makes sure per never be 0.

Good fix, thanks.

Acked-by: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>

>Signed-off-by: Wang Nan <wangnan0 at huawei.com>
>Cc: Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
>Cc: kexec at lists.infradead.org
>Cc: Geng Hui <hui.geng at huawei.com>
>Cc: Simon Horman <horms at verge.net.au>
>---
> makedumpfile.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index 23251a1..d71977a 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -5621,6 +5621,7 @@ write_elf_pages(struct cache_data *cd_header, struct cache_data *cd_page)
>
> 	num_dumpable = get_num_dumpable();
> 	per = num_dumpable / 10000;
>+	per = per ? per : 1;
>
> 	off_seg_load    = info->offset_load_dumpfile;
> 	cd_page->offset = info->offset_load_dumpfile;
>@@ -5906,6 +5907,7 @@ write_elf_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_page)
>
> 	num_dumpable = info->num_dumpable;
> 	per = num_dumpable / 10000;
>+	per = per ? per : 1;
>
> 	off_seg_load   = info->offset_load_dumpfile;
> 	cd_page->offset = info->offset_load_dumpfile;
>@@ -6164,6 +6166,7 @@ write_kdump_pages(struct cache_data *cd_header, struct cache_data *cd_page)
>
> 	num_dumpable = get_num_dumpable();
> 	per = num_dumpable / 10000;
>+	per = per ? per : 1;
>
> 	/*
> 	 * Calculate the offset of the page data.
>@@ -6365,6 +6368,7 @@ write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_pag
> 	}
>
> 	per = info->num_dumpable / 10000;
>+	per = per ? per : 1;
>
> 	/*
> 	 * Set a fileoffset of Physical Address 0x0.
>--
>1.8.4