Messages in this thread | | | Subject | Re: [PATCH] Longstanding elf fix (2.4.3 fix) | From | (Eric W. Biederman) | Date | 23 Apr 2001 01:44:57 -0600 |
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"David S. Miller" <davem@redhat.com> writes:
> Eric W. Biederman writes: > > In building a patch for 2.4.3 I also discovered that we are not taking > > the mmap_sem around do_brk in the exec paths. > > Does that really matter?
In the library loader I can certainly see it making a difference.
> Who else can get at the address space? > We are a singly referenced address space at that point... perhaps ptrace?
In practice I don't see it being a big deal. But reliable code is made by closing all of the little loop holes.
It also improves consistency as all of the calls to do_mmap are already protected in the exec paths.
And of course since much of the code in the kernel is built on the copy a good example neglecting the locking without a big comment, invites trouble elsewhere like in elf_load_library. Where we could have multiple threads running.
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