On Thu, Aug 10, 2023 at 12:29:48PM +0300, Jani Nikula wrote:
> On Fri, 04 Aug 2023, Jani Nikula <jani.nikula@xxxxxxxxx> wrote:
> > The current display probe is unable to differentiate between IVB Q and
> > IVB D GT2 server, as they both have the same device id, but different
> > subvendor and subdevice. This leads to the latter being misidentified as
> > the former, and should just end up not having a display. However, the no
> > display case returns a NULL as the display device info, and promptly
> > oopses.
> >
> > As the IVB Q case is rare, and we're anyway moving towards GMD ID,
> > handle the identification requiring subvendor and subdevice as a special
> > case first, instead of unnecessarily growing the intel_display_ids[]
> > array with subvendor and subdevice.
> >
> > [ 5.425298] BUG: kernel NULL pointer dereference, address: 0000000000000000
> > [ 5.426059] #PF: supervisor read access in kernel mode
> > [ 5.426810] #PF: error_code(0x0000) - not-present page
> > [ 5.427570] PGD 0 P4D 0
> > [ 5.428285] Oops: 0000 [#1] PREEMPT SMP PTI
> > [ 5.429035] CPU: 0 PID: 137 Comm: (udev-worker) Not tainted 6.4.0-1-amd64 #1 Debian 6.4.4-1
> > [ 5.429759] Hardware name: HP HP Z220 SFF Workstation/HP Z220 SFF Workstation, BIOS 4.19-218-gb184e6e0a1 02/02/2023
> > [ 5.430485] RIP: 0010:intel_device_info_driver_create+0xf1/0x120 [i915]
> > [ 5.431338] Code: 48 8b 97 80 1b 00 00 89 8f c0 1b 00 00 48 89 b7 b0 1b 00 00 48 89 97 b8 1b 00 00 0f b7 fd e8 76 e8 14 00 48 89 83 50 1b 00 00 <48> 8b 08 48 89 8b c4 1b 00 00 48 8b 48 08 48 89 8b cc 1b 00 00 8b
> > [ 5.432920] RSP: 0018:ffffb8254044fb98 EFLAGS: 00010206
> > [ 5.433707] RAX: 0000000000000000 RBX: ffff923076e80000 RCX: 0000000000000000
> > [ 5.434494] RDX: 0000000000000260 RSI: 0000000100001000 RDI: 000000000000016a
> > [ 5.435277] RBP: 000000000000016a R08: ffffb8254044fb00 R09: 0000000000000000
> > [ 5.436055] R10: ffff922d02761de8 R11: 00657361656c6572 R12: ffffffffc0e5d140
> > [ 5.436867] R13: ffff922d00b720d0 R14: 0000000076e80000 R15: ffff923078c0cae8
> > [ 5.437646] FS: 00007febd19a18c0(0000) GS:ffff92307c000000(0000) knlGS:0000000000000000
> > [ 5.438434] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 5.439218] CR2: 0000000000000000 CR3: 000000010256e002 CR4: 00000000001706f0
> > [ 5.440009] Call Trace:
> > [ 5.440824] <TASK>
> > [ 5.441611] ? __die+0x23/0x70
> > [ 5.442394] ? page_fault_oops+0x17d/0x4c0
> > [ 5.443173] ? exc_page_fault+0x7f/0x180
> > [ 5.443949] ? asm_exc_page_fault+0x26/0x30
> > [ 5.444756] ? intel_device_info_driver_create+0xf1/0x120 [i915]
> > [ 5.445652] ? intel_device_info_driver_create+0xea/0x120 [i915]
> > [ 5.446545] i915_driver_probe+0x7f/0xb60 [i915]
> > [ 5.447431] ? drm_privacy_screen_get+0x15c/0x1a0 [drm]
> > [ 5.448240] local_pci_probe+0x45/0xa0
> > [ 5.449013] pci_device_probe+0xc7/0x240
> > [ 5.449748] really_probe+0x19e/0x3e0
> > [ 5.450464] ? __pfx___driver_attach+0x10/0x10
> > [ 5.451172] __driver_probe_device+0x78/0x160
> > [ 5.451870] driver_probe_device+0x1f/0x90
> > [ 5.452601] __driver_attach+0xd2/0x1c0
> > [ 5.453293] bus_for_each_dev+0x88/0xd0
> > [ 5.453989] bus_add_driver+0x116/0x220
> > [ 5.454672] driver_register+0x59/0x100
> > [ 5.455336] i915_init+0x25/0xc0 [i915]
> > [ 5.456104] ? __pfx_i915_init+0x10/0x10 [i915]
> > [ 5.456882] do_one_initcall+0x5d/0x240
> > [ 5.457511] do_init_module+0x60/0x250
> > [ 5.458126] __do_sys_finit_module+0xac/0x120
> > [ 5.458721] do_syscall_64+0x60/0xc0
> > [ 5.459314] ? syscall_exit_to_user_mode+0x1b/0x40
> > [ 5.459897] ? do_syscall_64+0x6c/0xc0
> > [ 5.460510] entry_SYSCALL_64_after_hwframe+0x72/0xdc
> > [ 5.461082] RIP: 0033:0x7febd20b0eb9
> > [ 5.461648] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2f 1f 0d 00 f7 d8 64 89 01 48
> > [ 5.462905] RSP: 002b:00007fffabb1ba78 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> > [ 5.463554] RAX: ffffffffffffffda RBX: 0000561e6304f410 RCX: 00007febd20b0eb9
> > [ 5.464201] RDX: 0000000000000000 RSI: 00007febd2244f0d RDI: 0000000000000015
> > [ 5.464869] RBP: 00007febd2244f0d R08: 0000000000000000 R09: 000000000000000a
> > [ 5.465512] R10: 0000000000000015 R11: 0000000000000246 R12: 0000000000020000
> > [ 5.466124] R13: 0000000000000000 R14: 0000561e63032b60 R15: 000000000000000a
> > [ 5.466700] </TASK>
> > [ 5.467271] Modules linked in: i915(+) drm_buddy video crc32_pclmul sr_mod hid_generic wmi crc32c_intel i2c_algo_bit sd_mod cdrom drm_display_helper cec usbhid rc_core ghash_clmulni_intel hid sha512_ssse3 ttm sha512_generic xhci_pci ehci_pci xhci_hcd ehci_hcd nvme ahci drm_kms_helper nvme_core libahci t10_pi libata psmouse aesni_intel scsi_mod crypto_simd i2c_i801 scsi_common crc64_rocksoft_generic cryptd i2c_smbus drm lpc_ich crc64_rocksoft crc_t10dif e1000e usbcore crct10dif_generic usb_common crct10dif_pclmul crc64 crct10dif_common button
> > [ 5.469750] CR2: 0000000000000000
> > [ 5.470364] ---[ end trace 0000000000000000 ]---
> > [ 5.470971] RIP: 0010:intel_device_info_driver_create+0xf1/0x120 [i915]
> > [ 5.471699] Code: 48 8b 97 80 1b 00 00 89 8f c0 1b 00 00 48 89 b7 b0 1b 00 00 48 89 97 b8 1b 00 00 0f b7 fd e8 76 e8 14 00 48 89 83 50 1b 00 00 <48> 8b 08 48 89 8b c4 1b 00 00 48 8b 48 08 48 89 8b cc 1b 00 00 8b
> > [ 5.473034] RSP: 0018:ffffb8254044fb98 EFLAGS: 00010206
> > [ 5.473698] RAX: 0000000000000000 RBX: ffff923076e80000 RCX: 0000000000000000
> > [ 5.474371] RDX: 0000000000000260 RSI: 0000000100001000 RDI: 000000000000016a
> > [ 5.475045] RBP: 000000000000016a R08: ffffb8254044fb00 R09: 0000000000000000
> > [ 5.475725] R10: ffff922d02761de8 R11: 00657361656c6572 R12: ffffffffc0e5d140
> > [ 5.476405] R13: ffff922d00b720d0 R14: 0000000076e80000 R15: ffff923078c0cae8
> > [ 5.477124] FS: 00007febd19a18c0(0000) GS:ffff92307c000000(0000) knlGS:0000000000000000
> > [ 5.477811] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 5.478499] CR2: 0000000000000000 CR3: 000000010256e002 CR4: 00000000001706f0
> >
> > Fixes: 69d439818fe5 ("drm/i915/display: Make display responsible for probing its own IP")
>
> Sasha, after pushing this fix, I realized the bug report was against
> 6.4.4, but the above commit hit upstream in v6.5-rc1.
>
> Turns out it was automatically backported as a dependency:
>
> commit be2caaed96c55bb1fcd55a25e60d7b309ff49f2d
> Author: Matt Roper <matthew.d.roper@xxxxxxxxx>
> Date: Tue May 23 12:56:07 2023 -0700
>
> drm/i915/display: Make display responsible for probing its own IP
>
> [ Upstream commit 69d439818fe501e8c9e50d963a53cb596e36f9f7 ]
>
> Rather than selecting the display IP and feature flags at the same time
> the general PCI probing happens, move this step into the display code
> itself so that it can be more easily re-used outside of i915 (i.e., by
> the Xe driver).
>
> v2:
> - Make intel_display_device_probe() always return a non-NULL pointer
> and simplify copying of runtime_defaults. (Andrzej)
> v3:
> - Redefine INTEL_VGA_DEVICE/INTEL_QUANTA_DEVICE to eliminate a cast and
> an include of linux/mod_devicetable.h. (Jani)
> - Keep explicit memcpy for runtime defaults. (Jani)
>
> Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
> Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
> Acked-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> Link: https://patchwork.freedesktop.org/patch/msgid/20230523195609.73627-5-matthew.d.roper@xxxxxxxxx
> Stable-dep-of: 19db2062094c ("drm/i915: No 10bit gamma on desktop gen3 parts")
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> I'm a bit surprised and scared this kind of refactoring commit got
> backported to stable.
It was needed by a different change, as the "Stable-dep-of:" line shows.
> Do you have automation in place to backport the fixes to backported
> commits too? I didn't think to add Cc: stable in the commit.
Yes, we do have it, but it can lag a release or two.
thanks
greg k-h
