On Sat, 2018-08-04 at 11:00 +0200, Greg Kroah-Hartman wrote: > 4.4-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Shaul Triebitz <shaul.triebitz@xxxxxxxxx> > > [ Upstream commit 0f22e40053bd5378ad1e3250e65c574fd61c0cd6 ] > > Make sure the rx_allocator worker is canceled before running the > rx_init routine. rx_init frees and re-allocates all rxb's pages. The > rx_allocator worker also allocates pages for the used rxb's. Running > rx_init and rx_allocator simultaniously causes a kernel panic. Fix > that by canceling the work in rx_init. > > Signed-off-by: Shaul Triebitz <shaul.triebitz@xxxxxxxxx> > Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > drivers/net/wireless/iwlwifi/pcie/rx.c | 2 ++ > 1 file changed, 2 insertions(+) > > --- a/drivers/net/wireless/iwlwifi/pcie/rx.c > +++ b/drivers/net/wireless/iwlwifi/pcie/rx.c > @@ -713,6 +713,8 @@ int iwl_pcie_rx_init(struct iwl_trans *t > WQ_HIGHPRI | WQ_UNBOUND, 1); > INIT_WORK(&rba->rx_alloc, iwl_pcie_rx_allocator_work); > > + cancel_work_sync(&rba->rx_alloc); > + > spin_lock(&rba->lock); > atomic_set(&rba->req_pending, 0); > atomic_set(&rba->req_ready, 0); This seems to be an incomplete fix. INIT_WORK() will overwrite the list pointers in the work item, so there is still a race condition. I think that the RX initialisation and reinitialisation/reset cases need to be explicitly distinguished. In the initialisation case the driver should do only INIT_WORK() and in the reset case it should do only cancel_work_sync() (although it would be safe to do INIT_WORK() *after* that). Ben. -- Ben Hutchings, Software Developer Codethink Ltd https://www.codethink.co.uk/ Dale House, 35 Dale Street Manchester, M1 2HF, United Kingdom
