Messages in this thread |  | | | Date | Wed, 21 Oct 1998 11:24:55 +1300 | | From | Chris Wedgwood <> | | Subject | Re: Linux 2.1.125 doesn't dump core on SIGSEGV |
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On Tue, Oct 20, 1998 at 11:11:53PM +0100, David Woodhouse wrote:
> As you say, there's still a race. It's better to leave a gaping > hole which obviously needs fixing than a subtle one, so Linus > wouldn't accept it. > > How about: > > lock_vfs() > stat() > open() > unlock_vfs() > > As I said, it's only useful in the core dump case, but that's the > original context of this discussion. We can worry about safe temp > file creation later.
Hmm... I'm not sure how the lock_vfs semantics would work and no interfere with the stat and open calls.
Assuming that isn't a problem, this isn't a bad solution but it would suck rocks for time critical stuff (rt-linux?) which might be writing data out to disk, then some other process goes and dumps core on an old ESDI same-day-service disk with abysmal seeks times... (making the stat take a _long_ time, the open would be a (d)cache hit).
I'm thinking this is much harder than I envisaged, and we should declare core dumps and root `a bad thing' until we can get O_NOFOLLOW semantics in the vfs.
Perhaps a sysclt /proc/sys/kernel/allow_root_coredump ?
-cw
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