On Fri, Nov 22, 2013 at 05:31:46PM +0100, Daniel Lezcano wrote: > On 11/22/2013 05:16 PM, Thierry Reding wrote: > >On Sat, Oct 19, 2013 at 12:49:48AM +0200, Thierry Reding wrote: > >>When booting a recent kernel on ARM with OF_DYNAMIC enabled, the kernel > >>warns about the following: > >> > >> [ 0.000000] ERROR: Bad of_node_put() on /timer@50004600 > >> [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.0-rc5-next-20131017-00077-gedfd827-dirty #406 > >> [ 0.000000] [<c0015b68>] (unwind_backtrace+0x0/0xf4) from [<c00117e4>] (show_stack+0x10/0x14) > >> [ 0.000000] [<c00117e4>] (show_stack+0x10/0x14) from [<c055f734>] (dump_stack+0x9c/0xc8) > >> [ 0.000000] [<c055f734>] (dump_stack+0x9c/0xc8) from [<c03b47d4>] (of_node_release+0x90/0x9c) > >> [ 0.000000] [<c03b47d4>] (of_node_release+0x90/0x9c) from [<c03b5084>] (of_find_matching_node_and_match+0x78/0xb4) > >> [ 0.000000] [<c03b5084>] (of_find_matching_node_and_match+0x78/0xb4) from [<c07887c8>] (clocksource_of_init+0x60/0x70) > >> [ 0.000000] [<c07887c8>] (clocksource_of_init+0x60/0x70) from [<c076e99c>] (start_kernel+0x1f4/0x33c) > >> [ 0.000000] [<c076e99c>] (start_kernel+0x1f4/0x33c) from [<80008074>] (0x80008074) > >> > >>This is caused by clocksource_of_init() dropping a reference on the > >>device node that it never took. The reference taken by the loop is > >>implicitly dropped on subsequent iterations. See the implementation of > >>and the comment on top of the of_find_matching_node_and_match() > >>function for reference (no pun intended). I only saw the end of the comment saying: Returns a node pointer with refcount incremented, use of_node_put() on it when done. Maybe that could be improved to something like: /** * of_find_matching_node_and_match - Find a node based on an of_device_id * match table * @from: The node to start searching from or NULL, the node you pass * will not be searched, only the next one will; typically, you * pass what the previous call returned. * @matches: ... * @match: ... * * Reference counting: Puts a reference on @from and increases the * reference count of the returned node. */ > >> > >>Signed-off-by: Thierry Reding <treding@xxxxxxxxxx> > >>--- > >> drivers/clocksource/clksrc-of.c | 1 - > >> 1 file changed, 1 deletion(-) > > > >Can someone look at this? > > Yes. Sounds like I missed it. > > This regression has been introduced by: > > commit 326e31eebe61dc838e031ea16968b2cfb43443e3 > Author: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > Date: Tue Oct 1 11:00:53 2013 +0200 > > clocksource: Put nodes passed to CLOCKSOURCE_OF_DECLARE > callbacks centrally > > Instead of letting each driver call of_node_put do it centrally in the > loop that also calls the CLOCKSOURCE_OF_DECLARE callbacks. This is less > prone to error and also moves getting and putting the references > into the > same function. > > Consequently all respective of_node_put calls in drivers are removed. > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> > Acked-by: David Brown <davidb@xxxxxxxxxxxxxx> Still all but the hook in clocksource_of_init of this commit was correct, right? (Well, but this buggy hunk makes the commit log wrong.) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
