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kernel-fxtec-pro1x/drivers/pci/switch
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Logan Gunthorpe 12ce9fd7fc PCI/switchtec: Fix init_completion race condition with poll_wait() 
[ Upstream commit efbdc769601f4d50018bf7ca50fc9f7c67392ece ]

The call to init_completion() in mrpc_queue_cmd() can theoretically
race with the call to poll_wait() in switchtec_dev_poll().

  poll()			write()
    switchtec_dev_poll()   	  switchtec_dev_write()
      poll_wait(&s->comp.wait);      mrpc_queue_cmd()
			               init_completion(&s->comp)
				         init_waitqueue_head(&s->comp.wait)

To my knowledge, no one has hit this bug.

Fix this by using reinit_completion() instead of init_completion() in
mrpc_queue_cmd().

Fixes: 080b47def5 ("MicroSemi Switchtec management interface driver")

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lkml.kernel.org/r/20200313183608.2646-1-logang@deltatee.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-17 10:48:40 +02:00
..
Kconfig PCI: Add SPDX GPL-2.0 when no license was specified 2018-01-26 11:45:16 -06:00
Makefile PCI: Add SPDX GPL-2.0 when no license was specified 2018-01-26 11:45:16 -06:00
switchtec.c PCI/switchtec: Fix init_completion race condition with poll_wait() 2020-04-17 10:48:40 +02:00