From: James Hogan Date: Mon, 1 Jul 2013 12:44:10 +0000 (+0100) Subject: metag: kick: add missing irq_enter/exit to kick_handler() X-Git-Tag: v3.11-rc1~79^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f6b30d32d242243a967993789c4cf550d840727e;p=pandora-kernel.git metag: kick: add missing irq_enter/exit to kick_handler() kick_handler() doesn't have an irq_enter/exit pair, but it's used for handling SMP IPIs which require work to be done in softirqs, which are invoked from irq_exit() when the hard irq nest count reaches 0. The scheduler_ipi() callback in the IPI handler calls irq_enter/exit itself, but this is inside kick_handler()'s spin lock critical section, so if an invoked softirq issues an IPI the kick_handler() will be re-entered on the same CPU and will deadlock. This is easily fixed by adding the missing irq_enter/exit to kick_handler() so that the hard irq nest count doesn't reach 0 until after the spin lock has been released. Ideally the spin lock protected handler list will also be replaced by a lockless RCU protected list since it is certainly mostly read. That can be done in a later change though. Signed-off-by: James Hogan Acked-by: Thomas Gleixner --- Reading git-diff-tree failed