Re: [PATCH RESEND] coredump: Ensure proper size of sparse core files

From	David Miller <davem@davemloft.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH RESEND] coredump: Ensure proper size of sparse core files
Date	2017-01-17 04:50 +0100
Message-ID	<t0sWt-1EX-7@gated-at.bofh.it> (permalink)
References	<sMbsu-Yb-35@gated-at.bofh.it> <sYwKR-2sb-9@gated-at.bofh.it>
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From: Dave Kleikamp <dave.kleikamp@oracle.com>
Date: Wed, 11 Jan 2017 13:25:00 -0600

> If the last section of a core file ends with an unmapped or zero page,
> the size of the file does not correspond with the last dump_skip() call.
> gdb complains that the file is truncated and can be confusing to users.
> 
> After all of the vma sections are written, make sure that the file size
> is no smaller than the current file position.
> 
> This problem can be demonstrated with gdb's bigcore testcase on the
> sparc architecture.
> 
> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

The lseek() done by dump_skip() should extend the file properly.

Otherwise, everyone would be seeing this problem.

That test case passed all the time when I was last running the GDB
testsuite all the time on sparc64, say 5 years ago.

Thread

[PATCH RESEND] coredump: Ensure proper size of sparse core files Dave Kleikamp <dave.kleikamp@oracle.com> - 2017-01-11 20:30 +0100
  Re: [PATCH RESEND] coredump: Ensure proper size of sparse core  files David Miller <davem@davemloft.net> - 2017-01-17 04:50 +0100
    Re: [PATCH RESEND] coredump: Ensure proper size of sparse core files Christoph Hellwig <hch@infradead.org> - 2017-01-17 09:00 +0100
      Re: [PATCH RESEND] coredump: Ensure proper size of sparse core  files David Miller <davem@davemloft.net> - 2017-01-17 21:50 +0100
        Re: [PATCH RESEND] coredump: Ensure proper size of sparse core files Dave Kleikamp <dave.kleikamp@oracle.com> - 2017-01-17 22:10 +0100

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