Re: 2.6.18-rc4-mm1 BUG, drm relatedy

From: Dave Airlie
Date: Mon Aug 21 2006 - 07:22:26 EST



[ 40.276000] [drm:drm_unlock] *ERROR* Process 8914 using kernel context 0

Can you send me an lspci -v (or have you already??)

I've been busy lately so having trouble following this stuff in a timely manner, I think this is an error path which the userpsace code doesn't clean up properly, your patch is most definitely not correct..

if I had to guess I'd say you have an AGP machine + card but no AGP support driver loaded...

Dave.


[ 41.024000] BUG: unable to handle kernel paging request at virtual address 6e756f73
[ 41.024000] printing eip:
[ 41.024000] c01b5771
[ 41.024000] *pde = 00000000
[ 41.024000] Oops: 0000 [#1]
[ 41.024000] 8K_STACKS PREEMPT
[ 41.024000] last sysfs file: /devices/pci0000:00/0000:00:1d.7/usb5/5-0:1.0/bInterfaceProtocol
[ 41.024000] Modules linked in: snd_seq snd_seq_device ohci_hcd parport_pc parport pcspkr ipw2200 yenta_socket rsrc_nonstatic pcmcia_core snd_intel8x0 snd_ac97_codec snd_ac97_bus snd_pcm snd_timer snd soundcore snd_page_alloc ehci_hcd uhci_hcd usbcore cpufreq_stats cpufreq_powersave cpufreq_ondemand cpufreq_conservative speedstep_centrino freq_table processor ac battery i915 drm tg3 joydev tsdev
[ 41.024000] CPU: 0
[ 41.024000] EIP: 0060:[<c01b5771>] Not tainted VLI
[ 41.024000] EFLAGS: 00210246 (2.6.18-rc4-mm1-def01 #1)
[ 41.024000] EIP is at sysfs_lookup+0x65/0xb0
[ 41.024000] eax: f3161e40 ebx: f316842c ecx: f73f6280 edx: f316842c
[ 41.024000] esi: 6e756f73 edi: f3161ec4 ebp: f6c35dfc esp: f6c35de0
[ 41.024000] ds: 007b es: 007b ss: 0068
[ 41.024000] Process modprobe (pid: 8952, ti=f6c34000 task=f7d17550 task.ti=f6c34000)
[ 41.024000] Stack: f316842c f3161e94 f31684bc 00000000 fffffff4 f73f72ec f3161e40 f6c35e1c
[ 41.024000] c0184d42 f73f72ec f3161e40 00000000 ffffffff c03a6656 12fd28db f6c35e4c
[ 41.024000] c0184e02 f6c35e30 f3161ee8 00000000 12fd28db 00000005 c03a6651 c038230e
[ 41.024000] Call Trace:
[ 41.024000] [<c0184d42>] __lookup_hash+0x9d/0xcc
[ 41.024000] [<c0184e02>] lookup_one_len+0x71/0x86
[ 41.024000] [<c01b51da>] create_dir+0x43/0x23f
[ 41.024000] [<c01b53fc>] sysfs_create_subdir+0x26/0x28
[ 41.024000] [<c01b6c56>] sysfs_create_group+0x77/0x97
[ 41.024000] [<c02903af>] dpm_sysfs_add+0x1e/0x20
[ 41.024000] [<c028f6b3>] device_pm_add+0x64/0x89
[ 41.024000] [<c028930a>] device_add+0x1d9/0x380
[ 41.024000] [<c02894cb>] device_register+0x1a/0x20
[ 41.024000] [<c0289811>] device_create+0xaa/0xc4
[ 41.024000] [<f8a0c472>] snd_register_device+0xcf/0x104 [snd]
[ 41.024000] [<f8abd0c2>] snd_sequencer_device_init+0x4e/0x7c [snd_seq]
[ 41.024000] [<f8abd02f>] alsa_seq_init+0x2f/0x51 [snd_seq]
[ 41.024000] [<c014186c>] sys_init_module+0x163/0x221
[ 41.024000] [<c0103135>] sysenter_past_esp+0x56/0x8d
[ 41.024000] [<b7fb0410>] 0xb7fb0410
[ 41.024000] [<c0104017>] show_trace_log_lvl+0x2f/0x45
[ 41.024000] [<c01040ee>] show_stack_log_lvl+0x98/0xb2
[ 41.024000] [<c0104351>] show_registers+0x1eb/0x289
[ 41.024000] [<c0104587>] die+0x134/0x241
[ 41.024000] [<c0385e80>] do_page_fault+0x395/0x620
[ 41.024000] [<c0384401>] error_code+0x39/0x40
[ 41.024000] [<c0184d42>] __lookup_hash+0x9d/0xcc
[ 41.024000] [<c0184e02>] lookup_one_len+0x71/0x86
[ 41.024000] [<c01b51da>] create_dir+0x43/0x23f
[ 41.024000] [<c01b53fc>] sysfs_create_subdir+0x26/0x28
[ 41.024000] [<c01b6c56>] sysfs_create_group+0x77/0x97
[ 41.024000] [<c02903af>] dpm_sysfs_add+0x1e/0x20
[ 41.024000] [<c028f6b3>] device_pm_add+0x64/0x89
[ 41.024000] [<c028930a>] device_add+0x1d9/0x380
[ 41.024000] [<c02894cb>] device_register+0x1a/0x20
[ 41.024000] [<c0289811>] device_create+0xaa/0xc4
[ 41.024000] [<f8a0c472>] snd_register_device+0xcf/0x104 [snd]
[ 41.024000] [<f8abd0c2>] snd_sequencer_device_init+0x4e/0x7c [snd_seq]
[ 41.024000] [<f8abd02f>] alsa_seq_init+0x2f/0x51 [snd_seq]
[ 41.024000] [<c014186c>] sys_init_module+0x163/0x221
[ 41.024000] [<c0103135>] sysenter_past_esp+0x56/0x8d
[ 41.024000] =======================
[ 41.024000] Code: 42 fc 89 c3 8b 40 04 0f 18 00 90 3b 55 ec 75 e6 8b 45 f0 83 c4 10 5b 5e 5f 5d c3 89 1c 24 e8 27 e9 ff ff 89 c6 8b 45 0c 8b 78 48 <ac> ae 75 08 84 c0 75 f8 31 c0 eb 04 19 c0 0c 01 85 c0 75 bd f6
[ 41.024000] EIP: [<c01b5771>] sysfs_lookup+0x65/0xb0 SS:ESP 0068:f6c35de0
[ 41.024000]


Hi Andrew,

I think that this definitely qualifies as a drm bug. Here are the tests
that I did and that make me think so:
- Removing the line 'Load "dri"' from xorg.conf makes the oops
disappear.
- The bisection I performed indicates that the problem comes from the
following set of patches:
git-drm.patch
drm-build-fix.patch
drm-build-fixes-2.patch
allow-drm-detection-of-new-via-chipsets.patch
git-drm-build-fix.patch
- Appliying the attached patch makes the oops disapear too.

Now, I don't know the drm code, and I'm not able to explain why the fix
works... Any ideas?

Regards,
Frederik

Signed-off-by: Frederik Deweerdt <frederik.deweerdt@xxxxxxxxx>
diff --git a/drivers/char/drm/drm_lock.c b/drivers/char/drm/drm_lock.c
index f9e4530..a9e01b7 100644
--- a/drivers/char/drm/drm_lock.c
+++ b/drivers/char/drm/drm_lock.c
@@ -65,12 +65,6 @@ int drm_lock(struct inode *inode, struct
if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock)))
return -EFAULT;

- if (lock.context == DRM_KERNEL_CONTEXT) {
- DRM_ERROR("Process %d using kernel context %d\n",
- current->pid, lock.context);
- return -EINVAL;
- }
-
DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
lock.context, current->pid,
dev->lock.hw_lock->lock, lock.flags);


--
David Airlie, Software Engineer
http://www.skynet.ie/~airlied / airlied at skynet.ie
Linux kernel - DRI, VAX / pam_smb / ILUG

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