On Fri, Dec 10, 2010 at 08:00:49PM +0200, Timo Teräs wrote: > On 12/10/2010 07:35 PM, Greg KH wrote: > > On Fri, Dec 10, 2010 at 05:00:01PM +0200, Timo Teräs wrote: > >> osd_schedule_callback() is called from VmbusOnMsgDPC() which runs > >> in a tasklet. Avoid possible sleeping by using GFP_ATOMIC for the > >> memory allocation. > >> > >> Seems to fix #16701. > >> > >> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16701 > >> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > >> Cc: Hank Janssen <hjanssen@xxxxxxxxxxxxx> > >> Signed-off-by: Timo Teräs <timo.teras@xxxxxx> > >> --- > >> drivers/staging/hv/osd.c | 2 +- > >> 1 files changed, 1 insertions(+), 1 deletions(-) > >> > >> diff --git a/drivers/staging/hv/osd.c b/drivers/staging/hv/osd.c > >> index 8c3eb27..eb9b20d 100644 > >> --- a/drivers/staging/hv/osd.c > >> +++ b/drivers/staging/hv/osd.c > >> @@ -214,7 +214,7 @@ int osd_schedule_callback(struct workqueue_struct *wq, > >> { > >> struct osd_callback_struct *cb; > >> > >> - cb = kmalloc(sizeof(*cb), GFP_KERNEL); > >> + cb = kmalloc(sizeof(*cb), GFP_ATOMIC); > > > > How about just fixing the one place where this is needed? You don't > > need this for all of the osd_schedule_callback() functions, right? > > > > Actually, we should unroll this function entirely and use the "real" > > functions the kernel provides us. I'd much rather see that fix than > > this one which just papers over the problem. > > Yes, I agree. The osd_schedule_callback should definitely go away, we > could also get rid of this kmalloc() by allocating the workqueue_struct > as part of the callback context data which is the usual convention. Yes. > This was intended as minimum intrusion fix which would be suitable for > -stable. As this bug seems to be a major issue in certain configurations. No, fix the bug properly now, we will worry about older kernel releases later. > I'm not entirely sure about the usage of osd_schedule_callback() on > other cases. It would appear that only VmbusOnMsgDPC() needs the atomic > memory allocation. Then just "open code" the callback properly in that function to solve the issue. > I preferred to not change the signature of an exported symbol. Why not? It's just for these few modules, no big dea. > I can resubmit a version which adds the gfp_mask as parameter to > osd_schedule_callback if that would be acceptable for -stable. No, please fix it properly as described above. thanks, greg k-h _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
