linux/drivers/pci/switch
Logan Gunthorpe efbdc76960 PCI/switchtec: Fix init_completion race condition with poll_wait()
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
2020-03-21 16:00:20 +01:00
..
Kconfig docs: driver-api: add a series of orphaned documents 2019-07-15 11:03:02 -03:00
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() 2020-03-21 16:00:20 +01:00