Messages in this thread | | | Date | Fri, 15 Dec 2017 09:45:15 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH] drivers: base: power: Fix GFP_KERNEL in spinlock context |
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On Tue 2017-12-12 15:58:00, Geert Uytterhoeven wrote: > Hi Shrikant, > > On Tue, Dec 12, 2017 at 2:45 PM, <shrikant.maurya@techveda.org> wrote: > > From: Shrikant Maurya <shrikant.maurya@techveda.org> > > > > As reported by Jia-Ju Bai (https://lkml.org/lkml/2017/12/11/872): > > API's are using GFP_KERNEL to allocate memory which may sleep. > > > > To ensure atomicity such allocations must be avoided in critical > > sections under spinlock. > > Fixed by replacing GFP_KERNEL to GFP_ATOMIC. > > > > Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com> > > Signed-off-by: Shrikant Maurya <shrikant.maurya@techveda.org> > > Signed-off-by: Suniel Mahesh <sunil.m@techveda.org> > > Signed-off-by: Raghu Bharadwaj <raghu@techveda.org> > > Signed-off-by: Karthik Tummala <karthik@techveda.org> > > Can't the call to device_init_wakeup() in isp116x_start() just be moved > below the spinlock release? > > > --- a/drivers/base/power/wakeup.c > > +++ b/drivers/base/power/wakeup.c > > @@ -92,11 +92,11 @@ struct wakeup_source *wakeup_source_create(const char *name) > > { > > struct wakeup_source *ws; > > > > - ws = kmalloc(sizeof(*ws), GFP_KERNEL); > > + ws = kmalloc(sizeof(*ws), GFP_ATOMIC); > > With GFP_ATOMIC, allocation failure is much more likely to occur. > So IMHO it's better to fix the isp116x, than to impose this burden on > every user. > > > if (!ws) > > return NULL; > > > > - wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_KERNEL) : NULL); > > + wakeup_source_prepare(ws, name ? kstrdup_const(name, GFP_ATOMIC) : NULL); > > return ws;
NAK. This will silently replace name with NULL if memory is low.
Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [unhandled content-type:application/pgp-signature] | |