On Sat, Oct 31, 2015 at 03:15:12PM +0200, Noam Camus wrote: > From: Noam Camus <no...@ezchip.com> > > If we hold rw->lock_mutex and interrupt occures we may > end up spinning on it for ever during softirq. > > Below you may see an example for interrupt we get while > nl_table_lock is holding its rw->lock_mutex and we spinned > on it for ever. > > The concept for the fix was taken from SPARC. > > [2015-05-12 19:16:12] Stack Trace: > [2015-05-12 19:16:12] arc_unwind_core+0xb8/0x11c > [2015-05-12 19:16:12] dump_stack+0x68/0xac > [2015-05-12 19:16:12] _raw_read_lock+0xa8/0xac > [2015-05-12 19:16:12] netlink_broadcast_filtered+0x56/0x35c > [2015-05-12 19:16:12] nlmsg_notify+0x42/0xa4 > [2015-05-12 19:16:13] neigh_update+0x1fe/0x44c > [2015-05-12 19:16:13] neigh_event_ns+0x40/0xa4 > [2015-05-12 19:16:13] arp_process+0x46e/0x5a8 > [2015-05-12 19:16:13] __netif_receive_skb_core+0x358/0x500 > [2015-05-12 19:16:13] process_backlog+0x92/0x154 > [2015-05-12 19:16:13] net_rx_action+0xb8/0x188 > [2015-05-12 19:16:13] __do_softirq+0xda/0x1d8 > [2015-05-12 19:16:14] irq_exit+0x8a/0x8c > [2015-05-12 19:16:14] arch_do_IRQ+0x6c/0xa8 > [2015-05-12 19:16:14] handle_interrupt_level1+0xe4/0xf0 > > Signed-off-by: Noam Camus <no...@ezchip.com> > Cc: Peter Zijlstra <pet...@infradead.org>
It might make sense to note that this is a lock internal lock and since the lock is free to be used from any context, the lock needs to be IRQ-safe. Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
