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From: Thierry Reding <thierry.reding@gmail.com>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Rob Herring <rob.herring@calxeda.com>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] clocksource: Do not drop unheld reference on device node
Date: Sat, 19 Oct 2013 00:49:48 +0200	[thread overview]
Message-ID: <1382136588-15320-1-git-send-email-treding@nvidia.com> (raw)

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>
---
 drivers/clocksource/clksrc-of.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/clocksource/clksrc-of.c b/drivers/clocksource/clksrc-of.c
index 35639cf4..b9ddd9e 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);
 	}
 }
-- 
1.8.4


             reply	other threads:[~2013-10-18 22:52 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-18 22:49 Thierry Reding [this message]
2013-11-22 16:16 ` Thierry Reding
2013-11-22 16:31   ` Daniel Lezcano
2013-11-22 19:22     ` Uwe Kleine-König
2013-11-24 21:28       ` Daniel Lezcano
2013-11-25  7:29         ` Uwe Kleine-König
2013-11-25  8:57           ` Daniel Lezcano
2013-11-25  9:04             ` Thierry Reding
2013-11-25  8:59           ` Thierry Reding
2013-11-28  8:23 ` Daniel Lezcano

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