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authorIngo Molnar <mingo@elte.hu>2008-03-28 16:28:03 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2008-03-28 20:16:53 +0300
commit48d3d8263c491822d50e64547bae5f6b4a54ec59 (patch)
tree29f12143572f7ab00f309bce82c478042a899e7a /drivers/acpi/fan.c
parente72e9c23ee025a4c063ca112ba0a6059f9ecc9b7 (diff)
downloadlinux-48d3d8263c491822d50e64547bae5f6b4a54ec59.tar.xz
revert "ACPI: drivers/acpi: elide a non-zero test on a result that is never 0"
Revert commit 1192aeb957402b45f311895f124e4ca41206843c ("ACPI: drivers/acpi: elide a non-zero test on a result that is never 0") because it turns out that thermal_cooling_device_register() does actually return NULL if CONFIG_THERMAL is turned off (then the routine turns into a dummy inline routine in the header files that returns NULL unconditionally). This was found with randconfig testing, causing a crash during bootup: initcall 0x78878534 ran for 13 msecs: acpi_button_init+0x0/0x51() Calling initcall 0x78878585: acpi_fan_init+0x0/0x2c() BUG: unable to handle kernel NULL pointer dereference at 00000000 IP: [<782b8ad0>] acpi_fan_add+0x7d/0xfd *pde = 00000000 Oops: 0000 [#1] Modules linked in: Pid: 1, comm: swapper Not tainted (2.6.25-rc7-sched-devel.git-x86-latest.git #14) EIP: 0060:[<782b8ad0>] EFLAGS: 00010246 CPU: 0 EIP is at acpi_fan_add+0x7d/0xfd EAX: b787c718 EBX: b787c400 ECX: b782ceb4 EDX: 00000007 ESI: 00000000 EDI: b787c6f4 EBP: b782cee0 ESP: b782cecc DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 Process swapper (pid: 1, ti=b782c000 task=b7846000 task.ti=b782c000) Stack: b787c459 00000000 b787c400 78790888 b787c60c b782cef8 782b6fb8 ffffffda b787c60c 00000000 78790958 b782cf0c 783005d7 b787c60c 78790958 78790584 b782cf1c 783007f6 b782cf28 00000000 b782cf40 782ffc4a 78790958 b794d558 Call Trace: [<782b6fb8>] ? acpi_device_probe+0x3e/0xdb [<783005d7>] ? driver_probe_device+0x82/0xfc [<783007f6>] ? __driver_attach+0x3a/0x70 [<782ffc4a>] ? bus_for_each_dev+0x3e/0x60 [<7830048c>] ? driver_attach+0x14/0x16 [<783007bc>] ? __driver_attach+0x0/0x70 [<7830006a>] ? bus_add_driver+0x9d/0x1b0 [<783008c3>] ? driver_register+0x47/0xa3 [<7813db00>] ? timespec_to_ktime+0x9/0xc [<782b7331>] ? acpi_bus_register_driver+0x3a/0x3c [<78878592>] ? acpi_fan_init+0xd/0x2c [<78863656>] ? kernel_init+0xac/0x1f9 [<788635aa>] ? kernel_init+0x0/0x1f9 [<78114563>] ? kernel_thread_helper+0x7/0x10 ======================= Code: 6e 78 e8 57 44 e7 ff 58 e9 93 00 00 00 8b 55 f0 8d bb f4 02 00 00 80 4b 2d 10 8b 03 e8 87 cb ff ff 8d 83 18 03 00 00 80 63 2d ef <ff> 35 00 00 00 00 50 68 e8 9c 6e 78 e8 22 44 e7 ff b9 b6 9c 6e EIP: [<782b8ad0>] acpi_fan_add+0x7d/0xfd SS:ESP 0068:b782cecc ---[ end trace 778e504de7e3b1e3 ]--- Kernel panic - not syncing: Attempted to kill init! Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Julia Lawall <julia@diku.dk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/acpi/fan.c')
-rw-r--r--drivers/acpi/fan.c34
1 files changed, 18 insertions, 16 deletions
diff --git a/drivers/acpi/fan.c b/drivers/acpi/fan.c
index 4d535c50d821..c8e3cba423ef 100644
--- a/drivers/acpi/fan.c
+++ b/drivers/acpi/fan.c
@@ -260,22 +260,24 @@ static int acpi_fan_add(struct acpi_device *device)
result = PTR_ERR(cdev);
goto end;
}
- printk(KERN_INFO PREFIX
- "%s is registered as cooling_device%d\n",
- device->dev.bus_id, cdev->id);
-
- acpi_driver_data(device) = cdev;
- result = sysfs_create_link(&device->dev.kobj,
- &cdev->device.kobj,
- "thermal_cooling");
- if (result)
- return result;
-
- result = sysfs_create_link(&cdev->device.kobj,
- &device->dev.kobj,
- "device");
- if (result)
- return result;
+ if (cdev) {
+ printk(KERN_INFO PREFIX
+ "%s is registered as cooling_device%d\n",
+ device->dev.bus_id, cdev->id);
+
+ acpi_driver_data(device) = cdev;
+ result = sysfs_create_link(&device->dev.kobj,
+ &cdev->device.kobj,
+ "thermal_cooling");
+ if (result)
+ return result;
+
+ result = sysfs_create_link(&cdev->device.kobj,
+ &device->dev.kobj,
+ "device");
+ if (result)
+ return result;
+ }
result = acpi_fan_add_fs(device);
if (result)