From: ebiederm@xmission.com (Eric W. Biederman)
To: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: kexec@lists.infradead.org, heiko.carstens@de.ibm.com,
linux-kernel@vger.kernel.org, lisa.mitchell@hp.com,
kumagai-atsushi@mxc.nes.nec.co.jp, zhangyanfei@cn.fujitsu.com,
akpm@linux-foundation.org, cpw@sgi.com, vgoyal@redhat.com
Subject: Re: [PATCH v3 18/21] vmcore: check if vmcore objects satify mmap()'s page-size boundary requirement
Date: Wed, 20 Mar 2013 23:29:05 -0700 [thread overview]
Message-ID: <87ip4l1d1q.fsf@xmission.com> (raw)
In-Reply-To: <20130321.151428.393714972.d.hatayama@jp.fujitsu.com> (HATAYAMA Daisuke's message of "Thu, 21 Mar 2013 15:14:28 +0900 (JST)")
HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> writes:
>
> Do you mean for each range represented by each PT_LOAD entry, say:
>
> [p_paddr, p_paddr + p_memsz]
>
> extend it as:
>
> [rounddown(p_paddr, PAGE_SIZE), roundup(p_paddr + p_memsz, PAGE_SIZE)].
>
> not only objects in vmcore_list, but also updating p_paddr and p_memsz
> members themselves of each PT_LOAD entry? In other words, there's no
> new holes not referenced by any PT_LOAD entry since the regions
> referenced by some PT_LOAD entry, themselves are extended.
No. p_paddr and p_memsz as exported should remain the same.
I am suggesting that we change p_offset.
I am suggesting to include the data in the file as if we had changed
p_paddr and p_memsz.
> Then, the vmcores seen from read and mmap methods are coincide in the
> direction of including both ranges
>
> [rounddown(p_paddr, PAGE_SIZE), p_paddr]
>
> and
>
> [p_paddr + p_memsz, roundup(p_paddr + p_memsz, PAGE_SIZE)]
>
> are included in both vmcores seen from read and mmap methods, although
> they are originally not dump target memory, which you are not
> problematic for ease of implementation.
>
> Is there difference here from you understanding?
Preserving the actual PT_LOAD segments p_paddr and p_memsz values is
important. p_offset we can change as much as we want. Which means there
can be logical holes in the file between PT_LOAD segments, where we put
the extra data needed to keep everything page aligned.
Eric
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next prev parent reply other threads:[~2013-03-21 6:29 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-16 4:00 [PATCH v3 00/21] kdump, vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-03-16 4:00 ` [PATCH v3 01/21] vmcore: reference e_phoff member explicitly to get position of program header table HATAYAMA Daisuke
2013-03-19 21:44 ` Eric W. Biederman
2013-03-21 2:50 ` HATAYAMA Daisuke
2013-03-21 6:11 ` Eric W. Biederman
2013-03-21 14:12 ` Vivek Goyal
2013-03-22 0:25 ` HATAYAMA Daisuke
2013-03-16 4:00 ` [PATCH v3 02/21] vmcore: clean up by removing unnecessary variable HATAYAMA Daisuke
2013-03-16 4:01 ` [PATCH v3 03/21] vmcore: rearrange program headers without assuming consequtive PT_NOTE entries HATAYAMA Daisuke
2013-03-19 21:59 ` Eric W. Biederman
2013-03-16 4:01 ` [PATCH v3 04/21] vmcore, sysfs: export ELF note segment size instead of vmcoreinfo data size HATAYAMA Daisuke
2013-03-16 4:01 ` [PATCH v3 05/21] vmcore: allocate buffer for ELF headers on page-size alignment HATAYAMA Daisuke
2013-03-16 4:01 ` [PATCH v3 06/21] vmcore: round up buffer size of ELF headers by PAGE_SIZE HATAYAMA Daisuke
2013-03-19 22:07 ` Eric W. Biederman
2013-03-16 4:01 ` [PATCH v3 07/21] vmcore, procfs: introduce a flag to distinguish objects copied in 2nd kernel HATAYAMA Daisuke
2013-03-19 19:35 ` Andrew Morton
2013-03-16 4:01 ` [PATCH v3 08/21] vmcore: copy non page-size aligned head and tail pages " HATAYAMA Daisuke
2013-03-19 19:37 ` Andrew Morton
2013-03-19 20:59 ` Eric W. Biederman
2013-03-19 21:22 ` Vivek Goyal
2013-03-19 23:35 ` Eric W. Biederman
2013-03-16 4:01 ` [PATCH v3 09/21] vmcore: modify vmcore clean-up function to free buffer on " HATAYAMA Daisuke
2013-03-16 4:01 ` [PATCH v3 10/21] vmcore: clean up read_vmcore() HATAYAMA Daisuke
2013-03-16 4:01 ` [PATCH v3 11/21] vmcore: read buffers for vmcore objects copied from old memory HATAYAMA Daisuke
2013-03-16 4:01 ` [PATCH v3 12/21] vmcore: allocate per-cpu crash_notes objects on page-size boundary HATAYAMA Daisuke
2013-03-19 21:06 ` Eric W. Biederman
2013-03-19 22:12 ` Eric W. Biederman
2013-03-20 13:48 ` Vivek Goyal
2013-03-20 20:48 ` Eric W. Biederman
2013-03-16 4:02 ` [PATCH v3 13/21] kexec: allocate vmcoreinfo note buffer " HATAYAMA Daisuke
2013-03-19 21:07 ` Eric W. Biederman
2013-03-19 22:12 ` Eric W. Biederman
2013-03-16 4:02 ` [PATCH v3 14/21] kexec, elf: introduce NT_VMCORE_DEBUGINFO note type HATAYAMA Daisuke
2013-03-16 4:02 ` [PATCH v3 15/21] elf: introduce NT_VMCORE_PAD type HATAYAMA Daisuke
2013-03-16 4:02 ` [PATCH v3 16/21] kexec: fill note buffers by NT_VMCORE_PAD notes in page-size boundary HATAYAMA Daisuke
2013-03-19 22:17 ` Eric W. Biederman
2013-03-16 4:02 ` [PATCH v3 17/21] vmcore: check NT_VMCORE_PAD as a mark indicating the end of ELF note buffer HATAYAMA Daisuke
2013-03-19 21:11 ` Eric W. Biederman
2013-03-21 2:59 ` HATAYAMA Daisuke
2013-03-21 3:54 ` Eric W. Biederman
2013-03-21 14:36 ` Vivek Goyal
2013-03-22 0:30 ` HATAYAMA Daisuke
2013-03-22 0:41 ` Eric W. Biederman
2013-03-19 22:20 ` Eric W. Biederman
2013-03-16 4:02 ` [PATCH v3 18/21] vmcore: check if vmcore objects satify mmap()'s page-size boundary requirement HATAYAMA Daisuke
2013-03-19 20:02 ` Andrew Morton
2013-03-19 21:22 ` Eric W. Biederman
2013-03-20 13:51 ` Vivek Goyal
2013-03-19 22:38 ` Eric W. Biederman
2013-03-20 13:57 ` Vivek Goyal
2013-03-20 20:55 ` Eric W. Biederman
2013-03-21 3:25 ` HATAYAMA Daisuke
2013-03-21 4:18 ` Eric W. Biederman
2013-03-21 6:14 ` HATAYAMA Daisuke
2013-03-21 6:29 ` Eric W. Biederman [this message]
2013-03-21 6:46 ` HATAYAMA Daisuke
2013-03-21 7:07 ` Eric W. Biederman
2013-03-21 15:21 ` Vivek Goyal
2013-03-21 15:27 ` Vivek Goyal
2013-03-22 0:43 ` HATAYAMA Daisuke
2013-03-22 0:54 ` Eric W. Biederman
2013-03-22 2:30 ` HATAYAMA Daisuke
2013-03-21 14:57 ` Vivek Goyal
2013-03-21 7:22 ` Eric W. Biederman
2013-03-21 14:49 ` Vivek Goyal
2013-03-22 7:11 ` HATAYAMA Daisuke
2013-03-21 13:50 ` Vivek Goyal
2013-03-16 4:02 ` [PATCH v3 19/21] vmcore: round-up offset of vmcore object in page-size boundary HATAYAMA Daisuke
2013-03-16 4:02 ` [PATCH v3 20/21] vmcore: count holes generated by round-up operation for vmcore size HATAYAMA Daisuke
2013-03-16 4:02 ` [PATCH v3 21/21] vmcore: introduce mmap_vmcore() HATAYAMA Daisuke
2013-03-19 19:30 ` [PATCH v3 00/21] kdump, vmcore: support mmap() on /proc/vmcore Andrew Morton
2013-03-21 3:52 ` HATAYAMA Daisuke
2013-03-21 6:16 ` Eric W. Biederman
2013-03-21 6:35 ` HATAYAMA Daisuke
2013-03-21 7:14 ` Eric W. Biederman
2013-03-19 23:16 ` Eric W. Biederman
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