Re: Bug in net/ipv6/ip6_fib.c:fib6_dump_table()

[Eric Dumazet]

On Thu, 2012-06-21 at 14:35 -0500, Josh Hunt wrote:

> Can anyone provide details of the crash which was intended to be fixed
> by 2bec5a369ee79576a3eea2c23863325089785a2c? With this patch in and
> doing concurrent adds/deletes and dumping the table via netlink causes
> duplicate entries to be reported. Reverting this patch causes those
> problems to go away. We can provide a more detailed test if that is
> needed, but so far our testing has been unable to reproduce the crash
> mentioned in the above commit with it reverted.

A mere revert wont be enough.

Looking at this code, it lacks proper synchronization
between tree updaters and tree walkers.

fib6_walker_lock rwlock is not enough to prevent races.

Are you willing to fix this yourself ?



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