linux-kernel - [PATCH] s5p-mfc: Don't try to put pm->clock if lookup failed

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Message-Id: <1462210075-5320-1-git-send-email-javier@osg.samsung.com>
Date:	Mon,  2 May 2016 13:27:54 -0400
From:	Javier Martinez Canillas <javier@....samsung.com>
To:	linux-kernel@...r.kernel.org
Cc:	Marek Szyprowski <m.szyprowski@...sung.com>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Mauro Carvalho Chehab <mchehab@....samsung.com>,
	Kamil Debski <k.debski@...sung.com>,
	Jeongtae Park <jtp.park@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	linux-arm-kernel@...ts.infradead.org, linux-media@...r.kernel.org
Subject: [PATCH] s5p-mfc: Don't try to put pm->clock if lookup failed

Failing to get the struct s5p_mfc_pm .clock is a non-fatal error so the
clock field can have a errno pointer value. But s5p_mfc_final_pm() only
checks if .clock is not NULL before attempting to unprepare and put it.

This leads to the following warning in clk_put() due s5p_mfc_final_pm():

WARNING: CPU: 3 PID: 1023 at drivers/clk/clk.c:2814 s5p_mfc_final_pm+0x48/0x74 [s5p_mfc]
CPU: 3 PID: 1023 Comm: rmmod Tainted: G        W       4.6.0-rc6-next-20160502-00005-g5a15a49106bc #9
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[<c010e1bc>] (unwind_backtrace) from [<c010af28>] (show_stack+0x10/0x14)
[<c010af28>] (show_stack) from [<c032485c>] (dump_stack+0x88/0x9c)
[<c032485c>] (dump_stack) from [<c011b8e8>] (__warn+0xe8/0x100)
[<c011b8e8>] (__warn) from [<c011b9b0>] (warn_slowpath_null+0x20/0x28)
[<c011b9b0>] (warn_slowpath_null) from [<bf16004c>] (s5p_mfc_final_pm+0x48/0x74 [s5p_mfc])
[<bf16004c>] (s5p_mfc_final_pm [s5p_mfc]) from [<bf157414>] (s5p_mfc_remove+0x8c/0x94 [s5p_mfc])
[<bf157414>] (s5p_mfc_remove [s5p_mfc]) from [<c03fe1f8>] (platform_drv_remove+0x24/0x3c)
[<c03fe1f8>] (platform_drv_remove) from [<c03fcc70>] (__device_release_driver+0x84/0x110)
[<c03fcc70>] (__device_release_driver) from [<c03fcdd8>] (driver_detach+0xac/0xb0)
[<c03fcdd8>] (driver_detach) from [<c03fbff8>] (bus_remove_driver+0x4c/0xa0)
[<c03fbff8>] (bus_remove_driver) from [<c01886a8>] (SyS_delete_module+0x174/0x1b8)
[<c01886a8>] (SyS_delete_module) from [<c01078c0>] (ret_fast_syscall+0x0/0x3c)

So check if the pointer is not an errno value before calling clk_put().

Signed-off-by: Javier Martinez Canillas <javier@....samsung.com>

---

 drivers/media/platform/s5p-mfc/s5p_mfc_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/s5p-mfc/s5p_mfc_pm.c b/drivers/media/platform/s5p-mfc/s5p_mfc_pm.c
index 5f97a3398c11..d011f30be265 100644
--- a/drivers/media/platform/s5p-mfc/s5p_mfc_pm.c
+++ b/drivers/media/platform/s5p-mfc/s5p_mfc_pm.c
@@ -85,7 +85,7 @@ err_g_ip_clk:
 void s5p_mfc_final_pm(struct s5p_mfc_dev *dev)
 {
 	if (dev->variant->version != MFC_VERSION_V6 &&
-	    pm->clock) {
+	    !IS_ERR_OR_NULL(pm->clock)) {
 		clk_disable_unprepare(pm->clock);
 		clk_put(pm->clock);
 	}
-- 
2.5.5