diff options
| author | Logan Gunthorpe <logang@deltatee.com> | 2020-03-21 14:25:45 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-17 11:50:02 +0300 |
| commit | d1d846fb02a8e38625859e990377bafcb698ad1b (patch) | |
| tree | e65fe96546bdbc8d9c22d80c64257fcda6f7e7f4 | |
| parent | 75434bcc659394df665f01ebe0119cb638b7984a (diff) | |
| download | linux-d1d846fb02a8e38625859e990377bafcb698ad1b.tar.xz | |
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: 080b47def5e5 ("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>
| -rw-r--r-- | drivers/pci/switch/switchtec.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index cc43c855452f..2c9c3061894b 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -175,7 +175,7 @@ static int mrpc_queue_cmd(struct switchtec_user *stuser) kref_get(&stuser->kref); stuser->read_len = sizeof(stuser->data); stuser_set_state(stuser, MRPC_QUEUED); - init_completion(&stuser->comp); + reinit_completion(&stuser->comp); list_add_tail(&stuser->list, &stdev->mrpc_queue); mrpc_cmd_submit(stdev); |