[PATCH 3.16 038/158] powerpc/pseries: Failure on removing device node

[Greg Kroah-Hartman]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>

commit f1b3929c232784580e5d8ee324b6bc634e709575 upstream.

While running command "drmgr -c phb -r -s 'PHB 528'", following
backtrace jumped out because the target device node isn't marked
with OF_DETACHED by of_detach_node(), which caused by error
returned from memory hotplug related reconfig notifier when
disabling CONFIG_MEMORY_HOTREMOVE. The patch fixes it.

ERROR: Bad of_node_put() on /pci@800000020000210/ethernet@0
CPU: 14 PID: 2252 Comm: drmgr Tainted: G        W     3.16.0+ #427
Call Trace:
[c000000012a776a0] [c000000000013d9c] .show_stack+0x88/0x148 (unreliable)
[c000000012a77750] [c00000000083cd34] .dump_stack+0x7c/0x9c
[c000000012a777d0] [c0000000006807c4] .of_node_release+0x58/0xe0
[c000000012a77860] [c00000000038a7d0] .kobject_release+0x174/0x1b8
[c000000012a77900] [c00000000038a884] .kobject_put+0x70/0x78
[c000000012a77980] [c000000000681680] .of_node_put+0x28/0x34
[c000000012a77a00] [c000000000681ea8] .__of_get_next_child+0x64/0x70
[c000000012a77a90] [c000000000682138] .of_find_node_by_path+0x1b8/0x20c
[c000000012a77b40] [c000000000051840] .ofdt_write+0x308/0x688
[c000000012a77c20] [c000000000238430] .proc_reg_write+0xb8/0xd4
[c000000012a77cd0] [c0000000001cbeac] .vfs_write+0xec/0x1f8
[c000000012a77d70] [c0000000001cc3b0] .SyS_write+0x58/0xa0
[c000000012a77e30] [c00000000000a064] syscall_exit+0x0/0x98

Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/platforms/pseries/hotplug-memory.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -146,7 +146,7 @@ static inline int pseries_remove_membloc
 }
 static inline int pseries_remove_mem_node(struct device_node *np)
 {
-	return -EOPNOTSUPP;
+	return 0;
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 


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