mhiramat at redhat
Nov 26, 2009, 7:50 AM
Post #2 of 4
(135 views)
Permalink
|
|
Re: + binfmt-introduce-coredump-parameter-structure.patch added to -mm tree
[In reply to]
|
|
Hi Kosaki-san,
KOSAKI Motohiro wrote:
> Hi Hiramatsu-san,
>
>>
>> The patch titled
>> binfmt: introduce coredump parameter structure
>> has been added to the -mm tree. Its filename is
>> binfmt-introduce-coredump-parameter-structure.patch
>>
>> Before you just go and hit "reply", please:
>> a) Consider who else should be cc'ed
>> b) Prefer to cc a suitable mailing list as well
>> c) Ideally: find the original patch on the mailing list and do a
>> reply-to-all to that, adding suitable additional cc's
>>
>> *** Remember to use Documentation/SubmitChecklist when testing your code ***
>>
>> See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
>> out what to do about this
>>
>> The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
>>
>> ------------------------------------------------------
>> Subject: binfmt: introduce coredump parameter structure
>> From: Masami Hiramatsu <mhiramat [at] redhat>
>>
>> These patches are for fixing coredump mm->flags consistency issue.
>>
>> ---
>> 1787 if (mm->core_state || !get_dumpable(mm)) { <- (1)
>> 1788 up_write(&mm->mmap_sem);
>> 1789 put_cred(cred);
>> 1790 goto fail;
>> 1791 }
>> 1792
>> [...]
>> 1798 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ <-(2)
>> 1799 flag = O_EXCL; /* Stop rewrite attacks */
>> 1800 cred->fsuid = 0; /* Dump root private */
>> 1801 }
>> ---
>>
>> Since dumpable bits are not protected by lock, there is a chance to change
>> these bits between (1) and (2).
>>
>> To solve this issue, this patch copies mm->flags to
>> coredump_params.mm_flags at the beginning of do_coredump() and uses it
>> instead of get_dumpable() while dumping core. This series also introduce
>> coredump parameter structure for simplify bimfmt->core_dump interface.
>>
>>
>>
>> This patch:
>>
>> Introduce coredump parameter data structure (struct coredump_params) for
>> simplifying binfmt->core_dump() arguments. This also cleanup DUMP_WRITE()
>> in elf_core_dump() by style issue.
>
>
> This patch break ia64 because arch specific ELF_CORE_EXTRA_PHDRS and
> ELF_CORE_WRITE_EXTRA_DATA still use DUMP_WRITE. I expect this patch
> break uml too.
$ grep -r DUMP_WRITE arch/*/include
arch/ia64/include/asm/elf.h: DUMP_WRITE(&phdr, sizeof(phdr)); \
arch/ia64/include/asm/elf.h: DUMP_WRITE((void *) gate_phdrs[\
Oops, certainly, that's a problem.
IMHO, we should not do like that, all parameter required by a macro should be
specified explicitly, since it reduces readability so much...
I think we'd better make those macros inline function, check it's return value
for error handling.
What would you think about it?
Thank you,
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat [at] redhat
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo [at] vger
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
|
