From: Thierry Reding <thierry.reding@gmail.com>
Date: Fri, 18 Oct 2013 22:49:48 +0000 (+0200)
Subject: clocksource: clksrc-of: Do not drop unheld reference on device node
X-Git-Tag: firefly_0821_release~176^2~4761^2^2~3
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4c4b053235fa73db1ea241aa5a6b021afb0ed8db;p=firefly-linux-kernel-4.4.55.git

clocksource: clksrc-of: Do not drop unheld reference on device node

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).

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---

diff --git a/drivers/clocksource/clksrc-of.c b/drivers/clocksource/clksrc-of.c
index 35639cf4e5a2..b9ddd9e3a2f5 100644
--- a/drivers/clocksource/clksrc-of.c
+++ b/drivers/clocksource/clksrc-of.c
@@ -35,6 +35,5 @@ void __init clocksource_of_init(void)
 
 		init_func = match->data;
 		init_func(np);
-		of_node_put(np);
 	}
 }