From d2f6650a950dadd20667a04a9dc785f240d43695 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 29 Jan 2010 17:48:51 +0100 Subject: ACPI: Add NULL pointer check in acpi_bus_start If acpi_bus_add does not return a device and it's passed to acpi_bus_start, bad things will happen: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [] acpi_bus_start+0x14/0x24 ... [] acpiphp_bus_add+0xba/0x130 [acpiphp] [] enable_device+0x132/0x2ff [acpiphp] [] acpiphp_enable_slot+0xb8/0x130 [acpiphp] [] handle_hotplug_event_func+0x87/0x190 [acpiphp] Next patch would make this NULL pointer check obsolete, but better having one more than one missing... Signed-off-by: Thomas Renninger Acked-by: Bjorn Helgaas CC: stable@kernel.org Signed-off-by: Len Brown --- drivers/acpi/scan.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index ff9f6226085..8044583f303 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -1357,6 +1357,9 @@ int acpi_bus_start(struct acpi_device *device) { struct acpi_bus_ops ops; + if (!device) + return -EINVAL; + memset(&ops, 0, sizeof(ops)); ops.acpi_op_start = 1; -- cgit v1.2.3 From 7779688fc3d1ceddad84846a7b0affbe8e78ec6e Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 29 Jan 2010 17:48:52 +0100 Subject: ACPI: acpi_bus_{scan,bus,add}: return -ENODEV if no device was found Callers (acpi_memhotplug.c, dock.c and others) check for the return value of acpi_bus_add() and assume a valid device was returned in case zero was returned. Thus return -ENODEV if no device was found in acpi_bus_scan and propagate this through acpi_bus_add and acpi_bus_start. Also remove a confusing comment in acpiphp_glue.c, acpi_bus_scan will and cannot invoke if acpi_bus_add returns no valid device. Signed-off-by: Thomas Renninger Acked-by: Bjorn Helgaas Signed-off-by: Len Brown --- drivers/acpi/scan.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 8044583f303..3e009674f33 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -1336,9 +1336,25 @@ static int acpi_bus_scan(acpi_handle handle, struct acpi_bus_ops *ops, if (child) *child = device; - return 0; + + if (device) + return 0; + else + return -ENODEV; } +/* + * acpi_bus_add and acpi_bus_start + * + * scan a given ACPI tree and (probably recently hot-plugged) + * create and add or starts found devices. + * + * If no devices were found -ENODEV is returned which does not + * mean that this is a real error, there just have been no suitable + * ACPI objects in the table trunk from which the kernel could create + * a device and add/start an appropriate driver. + */ + int acpi_bus_add(struct acpi_device **child, struct acpi_device *parent, acpi_handle handle, int type) @@ -1348,8 +1364,7 @@ acpi_bus_add(struct acpi_device **child, memset(&ops, 0, sizeof(ops)); ops.acpi_op_add = 1; - acpi_bus_scan(handle, &ops, child); - return 0; + return acpi_bus_scan(handle, &ops, child); } EXPORT_SYMBOL(acpi_bus_add); @@ -1363,8 +1378,7 @@ int acpi_bus_start(struct acpi_device *device) memset(&ops, 0, sizeof(ops)); ops.acpi_op_start = 1; - acpi_bus_scan(device->handle, &ops, NULL); - return 0; + return acpi_bus_scan(device->handle, &ops, NULL); } EXPORT_SYMBOL(acpi_bus_start); -- cgit v1.2.3