This is a note to let you know that I've just added the patch titled ARM: OMAP2+: Fix device node reference counts to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm-omap2-fix-device-node-reference-counts.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Tue Dec 12 13:26:17 CET 2017 From: Guenter Roeck <linux@xxxxxxxxxxxx> Date: Sat, 4 Mar 2017 07:02:10 -0800 Subject: ARM: OMAP2+: Fix device node reference counts From: Guenter Roeck <linux@xxxxxxxxxxxx> [ Upstream commit 10e5778f54765c96fe0c8f104b7a030e5b35bc72 ] After commit 0549bde0fcb1 ("of: fix of_node leak caused in of_find_node_opts_by_path"), the following error may be reported when running omap images. OF: ERROR: Bad of_node_put() on /ocp@68000000 CPU: 0 PID: 0 Comm: swapper Not tainted 4.10.0-rc7-next-20170210 #1 Hardware name: Generic OMAP3-GP (Flattened Device Tree) [<c0310604>] (unwind_backtrace) from [<c030bbf4>] (show_stack+0x10/0x14) [<c030bbf4>] (show_stack) from [<c05add8c>] (dump_stack+0x98/0xac) [<c05add8c>] (dump_stack) from [<c05af1b0>] (kobject_release+0x48/0x7c) [<c05af1b0>] (kobject_release) from [<c0ad1aa4>] (of_find_node_by_name+0x74/0x94) [<c0ad1aa4>] (of_find_node_by_name) from [<c1215bd4>] (omap3xxx_hwmod_is_hs_ip_block_usable+0x24/0x2c) [<c1215bd4>] (omap3xxx_hwmod_is_hs_ip_block_usable) from [<c1215d5c>] (omap3xxx_hwmod_init+0x180/0x274) [<c1215d5c>] (omap3xxx_hwmod_init) from [<c120faa8>] (omap3_init_early+0xa0/0x11c) [<c120faa8>] (omap3_init_early) from [<c120fb2c>] (omap3430_init_early+0x8/0x30) [<c120fb2c>] (omap3430_init_early) from [<c1204710>] (setup_arch+0xc04/0xc34) [<c1204710>] (setup_arch) from [<c1200948>] (start_kernel+0x68/0x38c) [<c1200948>] (start_kernel) from [<8020807c>] (0x8020807c) of_find_node_by_name() drops the reference to the passed device node. The commit referenced above exposes this problem. To fix the problem, use of_get_child_by_name() instead of of_find_node_by_name(); of_get_child_by_name() does not drop the reference count of passed device nodes. While semantically different, we only look for immediate children of the passed device node, so of_get_child_by_name() is a more appropriate function to use anyway. Release the reference to the device node obtained with of_get_child_by_name() after it is no longer needed to avoid another device node leak. While at it, clean up the code and change the return type of omap3xxx_hwmod_is_hs_ip_block_usable() to bool to match its use and the return type of of_device_is_available(). Cc: Qi Hou <qi.hou@xxxxxxxxxxxxx> Cc: Peter Rosin <peda@xxxxxxxxxx> Cc: Rob Herring <robh@xxxxxxxxxx> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm/mach-omap2/omap_hwmod_3xxx_data.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) --- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c +++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c @@ -3828,16 +3828,20 @@ static struct omap_hwmod_ocp_if *omap3xx * Return: 0 if device named @dev_name is not likely to be accessible, * or 1 if it is likely to be accessible. */ -static int __init omap3xxx_hwmod_is_hs_ip_block_usable(struct device_node *bus, - const char *dev_name) +static bool __init omap3xxx_hwmod_is_hs_ip_block_usable(struct device_node *bus, + const char *dev_name) { + struct device_node *node; + bool available; + if (!bus) - return (omap_type() == OMAP2_DEVICE_TYPE_GP) ? 1 : 0; + return omap_type() == OMAP2_DEVICE_TYPE_GP; - if (of_device_is_available(of_find_node_by_name(bus, dev_name))) - return 1; + node = of_get_child_by_name(bus, dev_name); + available = of_device_is_available(node); + of_node_put(node); - return 0; + return available; } int __init omap3xxx_hwmod_init(void) Patches currently in stable-queue which might be from linux@xxxxxxxxxxxx are queue-4.9/arm-omap2-release-device-node-after-it-is-no-longer-needed.patch queue-4.9/arm-omap2-fix-device-node-reference-counts.patch