> -----Original Message-----
> From: piliu <piliu@xxxxxxxxxx>
> Sent: Monday, December 9, 2019 1:06 AM
> To: Hagio Kazuhito(萩尾 一仁) <k-hagio@xxxxxxxxxxxxx>; kexec@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH] makedumpfile: assign bitmap2 fd for sub process during refiltering
>
>
>
> On 12/07/2019 06:11 AM, Kazuhito Hagio wrote:
> > Hi Pingfan,
> >
> >> -----Original Message-----
> >> In refiltering mode, each sub process inherits bitmap2->fd from parent.
> >> Then they lseek()/read() on the same fd, which means that they interference
> >> with each other.
> >>
> >> This breaks the purpose of SPLITTING_FD_BITMAP(i) for each sub process.
> >> Fix it by assigning a sub process dedicated fd to bitmap2->fd.
> >>
> >> Signed-off-by: Pingfan Liu <piliu@xxxxxxxxxx>
> >
> > Thanks for the patch.
> > I'm still reading the code, but it might be better to apply this to bitmap1->fd
> > as well? see you next week..
> Yes. Although during my test, bitmap1 is not touched, but it is a
> reasonable step to against any future bug.
Reading the code, I think
- the issue might occur not only in refiltering, but also the first filtering
with --split and --work-dir option (forced non-cyclic mode).
- pefer to gather things for --split option into writeout_multiple_dumpfiles()
if we can, for readability.
So does the following patch work for you and your test?
I could not have reproduced the issue yet.
diff --git a/makedumpfile.c b/makedumpfile.c
index b9e9dfbd45ba..674c6a00e2dd 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -10091,6 +10091,10 @@ writeout_multiple_dumpfiles(void)
info->split_start_pfn = SPLITTING_START_PFN(i);
info->split_end_pfn = SPLITTING_END_PFN(i);
+ if (!info->flag_cyclic) {
+ info->bitmap1->fd = info->fd_bitmap;
+ info->bitmap2->fd = info->fd_bitmap;
+ }
if (!reopen_dump_memory())
exit(1);
if ((status = writeout_dumpfile()) == FALSE)
BTW, what do you see when the issue occurs? an error or broken dump?
Thanks,
Kazu
>
> Thanks,
> Pingfan
> >
> > Thanks,
> > Kazu
> >
> >> ---
> >> makedumpfile.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/makedumpfile.c b/makedumpfile.c
> >> index d76a435..1dc8640 100644
> >> --- a/makedumpfile.c
> >> +++ b/makedumpfile.c
> >> @@ -8857,7 +8857,8 @@ write_kdump_pages_and_bitmap_cyclic(struct cache_data *cd_header, struct cache_d
> >> if (info->flag_cyclic) {
> >> if (!prepare_bitmap2_buffer())
> >> return FALSE;
> >> - }
> >> + } else if (info->flag_refiltering)
> >> + info->bitmap2->fd = info->fd_bitmap;
> >>
> >> /*
> >> * Write pages and bitmap cyclically.
> >> --
> >> 2.7.5
> >>
> >
> >
> >
> > _______________________________________________
> > kexec mailing list
> > kexec@xxxxxxxxxxxxxxxxxxx
> > http://lists.infradead.org/mailman/listinfo/kexec
> >
>
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