3.1rc10 null pointer dereference ideapad_backlight_notify_power

DISCUSSION Sam Tygier 3 participants 6 messages Oct 19, 2011 – Oct 24, 2011 x86 platform drivers

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Sam Tygier

author

2011-10-19 11:17 UTC #0 lore raw

In kernels 3.1rc9 and 3.1rc10 (from the ubuntu mainline repo) I get a crash when disabling and then enabling the screen backlight with the alt+f2 key on a lenovo ideapad S12 (intel version). The crash does not occur with 3.0 kernels in ubuntu. I have not tested earlier 3.1 rcs.

The crash message scrolls to fast to see, it is not writen to a log, and i dont see it on a USB serial console (I may be doing something wrong, but I do see other messages during boot). I managed to get some photos of the message. interesting parts are:

BUG: unable to handle kernel NULL pointer dereference at 00000008
IP: [<f807b29e>]  ideapad_backlight_notify_power+0x2e/0x40 [ideapad_laptop]
*pde = 00000000
Oops: 0002 [#1] SMP

call trace functions:
ideapad_acpi_notify
acpi_device_notify
acpi_ev_notify_dispach
acpi_os_execute_deferred
process_one_work
? acpi_os_wait_events_complete
????????? can't read this one
kthread
kthread_bind
kernel_thread_helper

i put the photos at http://www.hep.manchester.ac.uk/u/sam/pub/ideapad/

if it would be helpfull, i could try a few more times for sharper photos. please let me know if there is any other useful information you need.

thanks,
sam

David Rientjes

2011-10-19 20:20 UTC #1 lore raw

Quoted 27 lines · Sam Tygier

In kernels 3.1rc9 and 3.1rc10 (from the ubuntu mainline repo) I get a crash when disabling and then enabling the screen backlight with the alt+f2 key on a lenovo ideapad S12 (intel version). The crash does not occur with 3.0 kernels in ubuntu. I have not tested earlier 3.1 rcs.
The crash message scrolls to fast to see, it is not writen to a log, and i dont see it on a USB serial console (I may be doing something wrong, but I do see other messages during boot). I managed to get some photos of the message. interesting parts are:
BUG: unable to handle kernel NULL pointer dereference at 00000008
IP: [<f807b29e>]  ideapad_backlight_notify_power+0x2e/0x40 [ideapad_laptop]
*pde = 00000000
Oops: 0002 [#1] SMP
call trace functions:
ideapad_acpi_notify
acpi_device_notify
acpi_ev_notify_dispach
acpi_os_execute_deferred
process_one_work
? acpi_os_wait_events_complete
????????? can't read this one
kthread
kthread_bind
kernel_thread_helper

Quoted 5 lines

i put the photos at http://www.hep.manchester.ac.uk/u/sam/pub/ideapad/
if it would be helpfull, i could try a few more times for sharper photos. please let me know if there is any other useful information you need.

Looks light it may be changed via the acpi video driver where ->blight is NULL. Adding Ike and Matthew to the cc.

Ike Panhc

2011-10-20 01:32 UTC #2 lore raw

Quoted 29 lines · David Rientjes

Quoted 27 lines · Sam Tygier
In kernels 3.1rc9 and 3.1rc10 (from the ubuntu mainline repo) I get a crash when disabling and then enabling the screen backlight with the alt+f2 key on a lenovo ideapad S12 (intel version). The crash does not occur with 3.0 kernels in ubuntu. I have not tested earlier 3.1 rcs.
The crash message scrolls to fast to see, it is not writen to a log, and i dont see it on a USB serial console (I may be doing something wrong, but I do see other messages during boot). I managed to get some photos of the message. interesting parts are:
BUG: unable to handle kernel NULL pointer dereference at 00000008
IP: [<f807b29e>]  ideapad_backlight_notify_power+0x2e/0x40 [ideapad_laptop]
*pde = 00000000
Oops: 0002 [#1] SMP
call trace functions:
ideapad_acpi_notify
acpi_device_notify
acpi_ev_notify_dispach
acpi_os_execute_deferred
process_one_work
? acpi_os_wait_events_complete
????????? can't read this one
kthread
kthread_bind
kernel_thread_helper

Quoted 9 lines

Quoted 5 lines
i put the photos at http://www.hep.manchester.ac.uk/u/sam/pub/ideapad/
if it would be helpfull, i could try a few more times for sharper photos. please let me know if there is any other useful information you need.
Looks light it may be changed via the acpi video driver where ->blight is NULL. Adding Ike and Matthew to the cc.

This issue has been reported[1] and patch[2] is ready.

[1] http://www.mail-archive.com/[email protected]/msg02340.html

[2] http://www.mail-archive.com/[email protected]/msg02343.html

    http://www.mail-archive.com/[email protected]/msg02346.html

Thanks for reporting this issue.

David Rientjes

2011-10-20 05:35 UTC #3 lore raw

Quoted 7 lines · Ike Panhc

This issue has been reported[1] and patch[2] is ready.
[1] http://www.mail-archive.com/[email protected]/msg02340.html
[2] http://www.mail-archive.com/[email protected]/msg02343.html
    http://www.mail-archive.com/[email protected]/msg02346.html

It certainly looks like the patch in [2] will fix the issue, but it looks like those are from a couple months ago and I'm still not seeing it in linux-next. Matthew, how is this going to Linus and will it be cc'd to [email protected]?

Sam Tygier

author

2011-10-24 21:51 UTC #4 lore raw

Quoted 6 lines · Ike Panhc

Quoted 5 lines
This issue has been reported[1] and patch[2] is ready.
[1] http://www.mail-archive.com/[email protected]/msg02340.html

Quoted 8 lines

Quoted 3 lines
[2] http://www.mail-archive.com/[email protected]/msg02343.html
http://www.mail-archive.com/[email protected]/msg02346.html
It certainly looks like the patch in [2] will fix the issue, but it looks like those are from a couple months ago and I'm still not seeing it in linux-next. Matthew, how is this going to Linus and will it be cc'd to [email protected]?

the patch works for me (i applied it to kernel between r10 and 3.1 final). for some reason i don't understand i had to apply the patch by hand.

my git diff says:

drivers/platform/x86/ideapad-laptop.c +0 -0

index 0c59541..36953bd 100644
@@ -492,6 +492,9 @@ static void ideapad_backlight_notify_power(struct ideapad_private *priv)

{
        unsigned long power;
        struct backlight_device *blightdev = priv->blightdev; +
+       if (!blightdev)
+               return;

        if (read_ec_data(ideapad_handle, 0x18, &power)) return;

i am not quite sure of the etiquette, should I repost the patch in its original form, or my version, or can someone else get this included.

thanks

sam

David Rientjes

Tested-by Sam Tygier

2011-10-24 23:12 UTC #5 lore raw

Quoted 10 lines · Sam Tygier

Quoted 10 lines · Ike Panhc
Quoted 8 lines
This issue has been reported[1] and patch[2] is ready.
[1] http://www.mail-archive.com/[email protected]/msg02340.html
[2] http://www.mail-archive.com/[email protected]/msg02343.html
http://www.mail-archive.com/[email protected]/msg02346.html

Quoted 8 lines

Quoted 4 lines
It certainly looks like the patch in [2] will fix the issue, but it looks like those are from a couple months ago and I'm still not seeing it in linux-next. Matthew, how is this going to Linus and will it be cc'd to [email protected]?
the patch works for me (i applied it to kernel between r10 and 3.1 final). for some reason i don't understand i had to apply the patch by hand.

So we can add your

Tested-by Sam Tygier <[email protected]>

to the patch.

Quoted 2 lines

i am not quite sure of the etiquette, should I repost the patch in its original form, or my version, or can someone else get this included.

This will go through Matthew's tree and hopefully also backported to stable through [email protected]. Matthew?