Re: Core dumps for threads

Alan Cox (alan@lxorguk.ukuu.org.uk)
Sat, 24 Feb 2001 21:57:44 +0000 (GMT)


> Can anyone explain why this test is in routine `do_coredump'
> in file `fs/exec.c' in the 2.4.0 kernel?
>
> if (!current->dumpable || atomic_read(&current->mm->mm_users) != 1)
> goto fail;
>
> The only thing the test on `mm_users' seems to be doing is stopping
> a thread process from dumping core. What's the rationale for this?

The I/O to dump the core would race other changes on the mm. The right fix
is probably to copy the mm (as fork does) then dump the copy.

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