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authorLinus Torvalds <torvalds@linux-foundation.org>2022-05-23 16:37:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-05-23 16:37:35 -0700
commit4b57dccc42a790cdf2a8cad110143feb8b35e563 (patch)
tree3a112be712b558a480aead8398f2e80e99344615 /lib
parent140e40e39a29c7dbc188d9b43831c3d5e089c960 (diff)
parent75d8cce128c516fe6cf4b8683e8fe1a59e919902 (diff)
Merge tag 'core-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irqpoll update from Thomas Gleixner: "A single update for irqpoll: Ensure that a raised soft interrupt is handled after pulling the blk_cpu_iopoll backlog from a unplugged CPU. This prevents that the CPU which runs that code reaches idle with soft interrupts pending" * tag 'core-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: lib/irq_poll: Prevent softirq pending leak in irq_poll_cpu_dead()
Diffstat (limited to 'lib')
-rw-r--r--lib/irq_poll.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/irq_poll.c b/lib/irq_poll.c
index 2f17b488d58e..2d5329a42105 100644
--- a/lib/irq_poll.c
+++ b/lib/irq_poll.c
@@ -188,14 +188,18 @@ EXPORT_SYMBOL(irq_poll_init);
static int irq_poll_cpu_dead(unsigned int cpu)
{
/*
- * If a CPU goes away, splice its entries to the current CPU
- * and trigger a run of the softirq
+ * If a CPU goes away, splice its entries to the current CPU and
+ * set the POLL softirq bit. The local_bh_disable()/enable() pair
+ * ensures that it is handled. Otherwise the current CPU could
+ * reach idle with the POLL softirq pending.
*/
+ local_bh_disable();
local_irq_disable();
list_splice_init(&per_cpu(blk_cpu_iopoll, cpu),
this_cpu_ptr(&blk_cpu_iopoll));
__raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
local_irq_enable();
+ local_bh_enable();
return 0;
}