On Tue, Aug 23, 2016 at 12:58:43PM +0300, Meelis Roos wrote:
> This on a P4 PC with 82865G chipset and onboard Intel graphics. 4.7.0
> worked fine, current 4.8 git shows NULL pointer dereference as shown
> below at the end of dmesg.
>
> [ 10.066261] BUG: unable to handle kernel NULL pointer dereference at
> 00000104
> [ 10.066273] IP: [<c16054b4>] mutex_lock+0xa/0x15
> [ 10.066287] *pde = 00000000
> [ 10.066295] Oops: 0002 [#1]
> [ 10.066302] Modules linked in: i915(+) video i2c_algo_bit drm_kms_helper
> syscopyarea sysfillrect sysimgblt fb_sys_fops drm iTCO_wdt
> iTCO_vendor_support ppdev evdev snd_intel8x0 snd_ac97_codec ac97_bus psmouse
> snd_pcm snd_timer snd pcspkr uhci_hcd ehci_pci soundcore sr_mod ehci_hcd
> serio_raw i2c_i801 usbcore i2c_smbus cdrom lpc_ich mfd_core rng_core e100 mii
> floppy parport_pc parport acpi_cpufreq button processor usb_common eeprom
> lm85 hwmon_vid autofs4
> [ 10.066378] CPU: 0 PID: 132 Comm: systemd-udevd Not tainted
> 4.8.0-rc3-00013-gef0e1ea #34
> [ 10.066389] Hardware name: MicroLink
> /D865GLC , BIOS BF86510A.86A.0077.P25.0508040031
> 08/04/2005
> [ 10.066401] task: f62db800 task.stack: f5970000
> [ 10.066409] EIP: 0060:[<c16054b4>] EFLAGS: 00010286 CPU: 0
> [ 10.066417] EIP is at mutex_lock+0xa/0x15
> [ 10.066424] EAX: 00000104 EBX: 00000104 ECX: 00000000 EDX: 80000000
> [ 10.066432] ESI: 00000000 EDI: 00000104 EBP: f5be8000 ESP: f5971b58
> [ 10.066439] DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068
> [ 10.066446] CR0: 80050033 CR2: 00000104 CR3: 35945000 CR4: 000006d0
> [ 10.066453] Stack:
> [ 10.066459] f503d740 f824dddf 00000000 f61170c0 f61170c0 f82371ae
> f850f40e 00000001
> [ 10.066476] f61170c0 f5971bcc f5be8000 f9c2d401 00000001 f8236fcc
> 00000001 00000000
> [ 10.066491] f5144014 f5be8104 00000008 f9c5267c 00000007 f61170c0
> f5144400 f9c4ff00
> [ 10.066507] Call Trace:
> [ 10.066526] [<f824dddf>] ? drm_modeset_lock_all+0x27/0xb3 [drm]
> [ 10.066545] [<f82371ae>] ? drm_encoder_cleanup+0x1a/0x132 [drm]
> [ 10.066559] [<f850f40e>] ? drm_atomic_helper_connector_reset+0x3f/0x5c
> [drm_kms_helper]
> [ 10.066644] [<f9c2d401>] ? intel_dvo_init+0x569/0x788 [i915]
Looks like an incorrect call to drm_encoder_cleanup() from the error
path. If we hit the error path we have never called drm_encoder_init.
Please try:
diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
index 47bdf9dad0d3..b9e5a63a7c9e 100644
--- a/drivers/gpu/drm/i915/intel_dvo.c
+++ b/drivers/gpu/drm/i915/intel_dvo.c
@@ -554,7 +554,6 @@ void intel_dvo_init(struct drm_device *dev)
return;
}
- drm_encoder_cleanup(&intel_encoder->base);
kfree(intel_dvo);
kfree(intel_connector);
}
--
Chris Wilson, Intel Open Source Technology Centre
