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007c80a549
As detect will use hw registers and may modify structures, it needs to be serialised by use of the dev->mode_config.mutex. Make it so. Otherwise, we may cause random crashes as the sysfs file is queried whilst a concurrent hotplug poll is being run. For example: [ 1189.189626] BUG: unable to handle kernel NULL pointer dereference at 00000100 [ 1189.189821] IP: [<e0c22019>] intel_tv_detect_type+0xa2/0x203 [i915] [ 1189.190020] *pde = 00000000 [ 1189.190104] Oops: 0000 [#1] SMP [ 1189.190209] last sysfs file: /sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-SVIDEO-1/status [ 1189.190412] Modules linked in: mperf cpufreq_conservative cpufreq_userspace cpufreq_powersave cpufreq_stats decnet uinput fuse loop joydev snd_hd a_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm i915 snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq drm_kms_helper snd_timer uvcvideo d rm snd_seq_device eeepc_laptop tpm_tis usbhid videodev i2c_algo_bit v4l1_compat snd sparse_keymap i2c_core hid serio_raw tpm psmouse evdev tpm_bios rfkill shpchp ac processor rng_c ore battery video power_supply soundcore pci_hotplug button output snd_page_alloc usb_storage uas ext3 jbd mbcache sd_mod crc_t10dif ata_generic ahci libahci ata_piix libata uhci_h cd ehci_hcd scsi_mod usbcore thermal atl2 thermal_sys nls_base [last unloaded: scsi_wait_scan] [ 1189.192007] [ 1189.192007] Pid: 1464, comm: upowerd Not tainted 2.6.37-2-686 #1 ASUSTeK Computer INC. 701/701 [ 1189.192007] EIP: 0060:[<e0c22019>] EFLAGS: 00010246 CPU: 0 [ 1189.192007] EIP is at intel_tv_detect_type+0xa2/0x203 [i915] [ 1189.192007] EAX: 00000000 EBX: dca74000 ECX: e0f68004 EDX: 00068004 [ 1189.192007] ESI: dd110c00 EDI: 400c0c37 EBP: dca7429c ESP: de365e2c [ 1189.192007] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 1189.192007] Process upowerd (pid: 1464, ti=de364000 task=dcc8acb0 task.ti=de364000) [ 1189.192007] Stack: Mar 15 03:43:23 hostname kernel: [ 1189.192007] e0c2cda4 70000000 400c0c30 00000000 dd111000 de365e54 de365f24 dd110c00 [ 1189.192007] e0c22203 01000000 00000003 00000000 00000000 00000000 00000000 4353544e [ 1189.192007] 30383420 00000069 00000000 00000000 00000000 00000000 00000000 00000000 [ 1189.192007] Call Trace: Mar 15 03:43:23 hostname kernel: [ 1189.192007] [<e0c22203>] ? intel_tv_detect+0x89/0x12d [i915] [ 1189.192007] [<e0a9dcef>] ? status_show+0x0/0x2f [drm] [ 1189.192007] [<e0a9dd03>] ? status_show+0x14/0x2f [drm] [Digression: what is upowerd doing reading those power hungry files?] Reported-by: Paul Menzel <paulepanter@users.sourceforge.net> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: stable@kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com> |
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| Makefile | ||