Messages in this thread | | | Date | Wed, 25 Jan 2006 21:21:42 +0100 | From | Ingo Molnar <> | Subject | Re: [patch, validator] fix proc_subdir_lock related deadlock |
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* Andrew Morton <akpm@osdl.org> wrote:
> > to solve this we must either change files_lock to be softirq-safe too > > (bleh!), or we must forbid remove_proc_entry() use from softirq > > contexts. Neither is a happy solution - remove_proc_entry() is used > > within free_irq(), and who knows how many drivers do free_irq() in > > softirq/tasklet context ... > > free_irq()'s /proc fiddling has always been a pain - we just shouldn't > be doing filesystem things in irq/bh context.
the second patch i sent is quite straightforward.
> > Andrew, this needs to be resolved before v2.6.16, correct? Steve's patch > > solves a real bug in the upstream kernel. > > It's not a very big bug - I think only Steve hit it, and that with a > stress-test which was somewhat tuned to hit it.
still ...
> So we can afford to sit on the problem for a while, as long as someone > is working on a broader /proc-sanity fix. But nobody will do that. > > I wonder if we can just punt the unregister_handler_proc/kfree up to a > keventd callback.
i'd rather do the files_lock change i sent, and perhaps add a WARN_ON_ONCE() to all known places that do a free_irq() from softirq context.
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