From ce0d3c0a6fb1422101498ef378c0851dabbbf67f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 14 Jul 2015 22:03:57 +0200 Subject: genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for now Boris reported that the sparse_irq protection around __cpu_up() in the generic code causes a regression on Xen. Xen allocates interrupts and some more in the xen_cpu_up() function, so it deadlocks on the sparse_irq_lock. There is no simple fix for this and we really should have the protection for all architectures, but for now the only solution is to move it to x86 where actual wreckage due to the lack of protection has been observed. Reported-and-tested-by: Boris Ostrovsky Fixes: a89941816726 'hotplug: Prevent alloc/free of irq descriptors during cpu up/down' Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: xiao jin Cc: Joerg Roedel Cc: Borislav Petkov Cc: Yanmin Zhang Cc: xen-devel --- kernel/cpu.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'kernel') diff --git a/kernel/cpu.c b/kernel/cpu.c index 6a37454..5644ec5 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -527,18 +527,9 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen) goto out_notify; } - /* - * Some architectures have to walk the irq descriptors to - * setup the vector space for the cpu which comes online. - * Prevent irq alloc/free across the bringup. - */ - irq_lock_sparse(); - /* Arch-specific enabling code. */ ret = __cpu_up(cpu, idle); - irq_unlock_sparse(); - if (ret != 0) goto out_notify; BUG_ON(!cpu_online(cpu)); -- cgit v1.1