4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> commit 36c7c9da40c408a71e5e6bfe12e57dcf549a296d upstream. The WARN_ON() causes unnecessary backtrace when putting the parent slot, which is likely to be NULL. WARNING: CPU: 2 PID: 1071 at drivers/pci/hotplug/pnv_php.c:85 \ pnv_php_release+0xcc/0x150 [pnv_php] : Call Trace: [c0000003bc007c10] [d00000000ad613c4] pnv_php_release+0x144/0x150 [pnv_php] [c0000003bc007c40] [c0000000006641d8] pci_hp_deregister+0x238/0x330 [c0000003bc007cd0] [d00000000ad61440] pnv_php_unregister_one+0x70/0xa0 [pnv_php] [c0000003bc007d10] [d00000000ad614c0] pnv_php_unregister+0x50/0x80 [pnv_php] [c0000003bc007d40] [d00000000ad61e84] pnv_php_exit+0x50/0xcb4 [pnv_php] [c0000003bc007d70] [c00000000019499c] SyS_delete_module+0x1fc/0x2a0 [c0000003bc007e30] [c00000000000b184] system_call+0x38/0xe0 Fixes: 66725152fb9f ("PCI/hotplug: PowerPC PowerNV PCI hotplug driver") Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx> Reviewed-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx> Tested-by: Vaibhav Jain <vaibhav@xxxxxxxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/pci/hotplug/pnv_php.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -82,7 +82,7 @@ static void pnv_php_free_slot(struct kre static inline void pnv_php_put_slot(struct pnv_php_slot *php_slot) { - if (WARN_ON(!php_slot)) + if (!php_slot) return; kref_put(&php_slot->kref, pnv_php_free_slot);