Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: lock-up with module: Optimize __module_address() using a latched RB-tree | Date | Wed, 08 Jul 2015 10:25:40 +0930 |
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Peter Zijlstra <peterz@infradead.org> writes: > On Tue, Jul 07, 2015 at 11:56:20PM +0200, Peter Zijlstra wrote: >> On Wed, Jul 08, 2015 at 05:45:45AM +0930, Arthur Marsh wrote: >> > I'm not aware of any modules being loaded with --force . >> > >> > I've applied the patch, thanks! >> > >> > The resultant kernel locked up as follows: >> > >> > http://www.users.on.net/~arthur.marsh/20150708469.jpg >> >> This has "Not tainted" which would indeed rule out forced loading. So >> much for that idea :/ >> >> > http://www.users.on.net/~arthur.marsh/20150708470.jpg >> >> And that one has a bunch of NMI prints, curious those. But given Mathieu >> made them return NULL, that completely rules out the most interesting >> races. > > Could you try the below? It appears there was a spot freeing modules > that forgot to take them out of the tree.
Ouch! Good catch.
I'm testing that here.... Yep, "modprobe lp reset=7" (which fails to parse) three times and then oops in __mod_tree_insert.
If you want to wrap that with a SOB and Reported-by/Tested-by if my compatriot acks...
Thanks! Rusty.
> --- > kernel/module.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/module.c b/kernel/module.c > index 3e0e19763d24..4d2b82e610e2 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -3557,6 +3557,7 @@ static int load_module(struct load_info *info, const char __user *uargs, > mutex_lock(&module_mutex); > /* Unlink carefully: kallsyms could be walking list. */ > list_del_rcu(&mod->list); > + mod_tree_remove(mod); > wake_up_all(&module_wq); > /* Wait for RCU-sched synchronizing before releasing mod->list. */ > synchronize_sched();
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