On Fri, 5 Mar 2021 06:49:14 +0100 Christophe Leroy <christophe.le...@csgroup.eu> wrote:
> Le 05/03/2021 ?? 02:43, angkery a ??crit?0?2: > > From: Junlin Yang <yangjun...@yulong.com> > > > > ibmvnic_remove locks multiple spinlocks while disabling interrupts: > > spin_lock_irqsave(&adapter->state_lock, flags); > > spin_lock_irqsave(&adapter->rwi_lock, flags); > > > > there is no need for the second irqsave,since interrupts are > > disabled at that point, so remove the second irqsave: > > The probl??me is not that there is no need. The problem is a lot more > serious: As reported by coccinella, the second _irqsave() overwrites > the value saved in 'flags' by the first _irqsave, therefore when the > second _irqrestore comes, the value in 'flags' is not valid, the > value saved by the first _irqsave has been lost. This likely leads to > IRQs remaining disabled, which is _THE_ problem really. > Thank you for explaining the real problem. I will update the commit information with your description. > > spin_lock_irqsave(&adapter->state_lock, flags); > > spin_lock(&adapter->rwi_lock); > > > > Generated by: ./scripts/coccinelle/locks/flags.cocci > > ./drivers/net/ethernet/ibm/ibmvnic.c:5413:1-18: > > ERROR: nested lock+irqsave that reuses flags from line 5404. > > > > Signed-off-by: Junlin Yang <yangjun...@yulong.com> > > --- > > drivers/net/ethernet/ibm/ibmvnic.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c > > b/drivers/net/ethernet/ibm/ibmvnic.c index 2464c8a..a52668d 100644 > > --- a/drivers/net/ethernet/ibm/ibmvnic.c > > +++ b/drivers/net/ethernet/ibm/ibmvnic.c > > @@ -5408,9 +5408,9 @@ static void ibmvnic_remove(struct vio_dev > > *dev) > > * after setting state, so __ibmvnic_reset() which is > > called > > * from the flush_work() below, can make progress. > > */ > > - spin_lock_irqsave(&adapter->rwi_lock, flags); > > + spin_lock(&adapter->rwi_lock); > > adapter->state = VNIC_REMOVING; > > - spin_unlock_irqrestore(&adapter->rwi_lock, flags); > > + spin_unlock(&adapter->rwi_lock); > > > > spin_unlock_irqrestore(&adapter->state_lock, flags); > > > >
