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Date: Tue, 17 Sep 2013 15:09:26 -0400 From: Peter Hurley <peter@...leysoftware.com> To: johnflux <johnflux@...il.com> CC: linux-kernel@...r.kernel.org Subject: Re: Deadlock in fb and tty On 09/12/2013 09:22 AM, johnflux wrote: > The following seems to be better: > > From d93c1e9761ff66365d658da7d8d0d33823aa946f Mon Sep 17 00:00:00 2001 > From: John Tapsell<johnflux@...il.com> > Date: Thu, 12 Sep 2013 09:16:12 +0100 > Subject: [PATCH] Fix deadlock between fb_info and console. Do not lock > fb_info when calling sending the FB_EVENT_CONBLANK > > In fbmem.c, the semantics are that we acquire the lock_fb_info first, > and then console_lock. However when fbcon.c fbcon_generic_blank() is > called, the console lock could already be held. Locking fb_info can > thus cause a deadlock. > > fbmem.c sends the FB_EVENT_BLANK without locking lock_fb_info first, so > this change introduces similar behaviour. > --- > drivers/video/console/fbcon.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c > index 6b4fb5c..8546441 100644 > --- a/drivers/video/console/fbcon.c > +++ b/drivers/video/console/fbcon.c > @@ -2333,13 +2333,9 @@ static void fbcon_generic_blank(struct vc_data *vc, > struct fb_info *info, > vc->vc_video_erase_char = oldc; > } > > - > - if (!lock_fb_info(info)) > - return; > event.info = info; > event.data = ␣ > fb_notifier_call_chain(FB_EVENT_CONBLANK, &event); > - unlock_fb_info(info); > } > > static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch) > -- 1.8.1.2 > How can I get this reviewed/acked please? The get_maintainer.pl script can help to discover to whom to address patches. For example, peter@...r:~/src/kernels/next$ ./scripts/get_maintainer.pl -f drivers/video/console/fbcon.c Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com> (maintainer:FRAMEBUFFER LAYER) Tomi Valkeinen <tomi.valkeinen@...com> (maintainer:FRAMEBUFFER LAYER) Dave Airlie <airlied@...hat.com> (commit_signer:5/11=45%) Greg Kroah-Hartman <gregkh@...uxfoundation.org> (commit_signer:4/11=36%) Wang YanQing <udknight@...il.com> (commit_signer:4/11=36%) Andrew Morton <akpm@...ux-foundation.org> (commit_signer:3/11=27%) Kamal Mostafa <kamal@...nce.com> (commit_signer:1/11=9%) linux-fbdev@...r.kernel.org (open list:FRAMEBUFFER LAYER) linux-kernel@...r.kernel.org (open list) In this case, you'll want to send this patch addressed to the two maintainers and cc linux-fbdev and linux-kernel. You can cc me if you want. This is covered in Documentation/SubmittingPatches, which also covers the required subject line format <hint: too long, needs subsystem identifier>. Also, if you have the lockdep report of the deadlock, it's customary to include it in the commit message. Regards, Peter Hurley PS - Don't put stuff after the '--' tag at the end of the patch. Many mailers treat that as don't care. I missed your question first time around because Thunderbird grays that text :( -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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