mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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541ff7e96c
Turns out that if you trigger an HPD storm on a system that has an MST
topology connected to it, you'll end up causing the kernel to eventually
hit a NULL deref:
[ 332.339041] BUG: unable to handle kernel NULL pointer dereference at 00000000000000ec
[ 332.340906] PGD 0 P4D 0
[ 332.342750] Oops: 0000 [#1] SMP PTI
[ 332.344579] CPU: 2 PID: 25 Comm: kworker/2:0 Kdump: loaded Tainted: G O 4.18.0-rc3short-hpd-storm+ #2
[ 332.346453] Hardware name: LENOVO 20BWS1KY00/20BWS1KY00, BIOS JBET71WW (1.35 ) 09/14/2018
[ 332.348361] Workqueue: events intel_hpd_irq_storm_reenable_work [i915]
[ 332.350301] RIP: 0010:intel_hpd_irq_storm_reenable_work.cold.3+0x2f/0x86 [i915]
[ 332.352213] Code: 00 00 ba e8 00 00 00 48 c7 c6 c0 aa 5f a0 48 c7 c7 d0 73 62 a0 4c 89 c1 4c 89 04 24 e8 7f f5 af e0 4c 8b 04 24 44 89 f8 29 e8 <41> 39 80 ec 00 00 00 0f 85 43 13 fc ff 41 0f b6 86 b8 04 00 00 41
[ 332.354286] RSP: 0018:ffffc90000147e48 EFLAGS: 00010006
[ 332.356344] RAX: 0000000000000005 RBX: ffff8802c226c9d4 RCX: 0000000000000006
[ 332.358404] RDX: 0000000000000000 RSI: 0000000000000082 RDI: ffff88032dc95570
[ 332.360466] RBP: 0000000000000005 R08: 0000000000000000 R09: ffff88031b3dc840
[ 332.362528] R10: 0000000000000000 R11: 000000031a069602 R12: ffff8802c226ca20
[ 332.364575] R13: ffff8802c2268000 R14: ffff880310661000 R15: 000000000000000a
[ 332.366615] FS: 0000000000000000(0000) GS:ffff88032dc80000(0000) knlGS:0000000000000000
[ 332.368658] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 332.370690] CR2: 00000000000000ec CR3: 000000000200a003 CR4: 00000000003606e0
[ 332.372724] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 332.374773] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 332.376798] Call Trace:
[ 332.378809] process_one_work+0x1a1/0x350
[ 332.380806] worker_thread+0x30/0x380
[ 332.382777] ? wq_update_unbound_numa+0x10/0x10
[ 332.384772] kthread+0x112/0x130
[ 332.386740] ? kthread_create_worker_on_cpu+0x70/0x70
[ 332.388706] ret_from_fork+0x35/0x40
[ 332.390651] Modules linked in: i915(O) vfat fat joydev btusb btrtl btbcm btintel bluetooth ecdh_generic iTCO_wdt wmi_bmof i2c_algo_bit drm_kms_helper intel_rapl syscopyarea sysfillrect x86_pkg_temp_thermal sysimgblt coretemp fb_sys_fops crc32_pclmul drm psmouse pcspkr mei_me mei i2c_i801 lpc_ich mfd_core i2c_core tpm_tis tpm_tis_core thinkpad_acpi wmi tpm rfkill video crc32c_intel serio_raw ehci_pci xhci_pci ehci_hcd xhci_hcd [last unloaded: i915]
[ 332.394963] CR2: 00000000000000ec
This appears to be due to the fact that with an MST topology, not all
intel_connector structs will have ->encoder set. So, fix this by
skipping connectors without encoders in
intel_hpd_irq_storm_reenable_work().
For those wondering, this bug was found on accident while simulating HPD
storms using a Chamelium connected to a ThinkPad T450s (Broadwell).
Changes since v1:
- Check intel_connector->mst_port instead of intel_connector->encoder
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181106213017.14563-3-lyude@redhat.com
(cherry picked from commit
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.. | ||
amd | ||
arc | ||
arm | ||
armada | ||
ast | ||
atmel-hlcdc | ||
bochs | ||
bridge | ||
cirrus | ||
etnaviv | ||
exynos | ||
fsl-dcu | ||
gma500 | ||
hisilicon | ||
i2c | ||
i810 | ||
i915 | ||
imx | ||
lib | ||
mediatek | ||
meson | ||
mga | ||
mgag200 | ||
msm | ||
mxsfb | ||
nouveau | ||
omapdrm | ||
panel | ||
pl111 | ||
qxl | ||
r128 | ||
radeon | ||
rcar-du | ||
rockchip | ||
savage | ||
scheduler | ||
selftests | ||
shmobile | ||
sis | ||
sti | ||
stm | ||
sun4i | ||
tdfx | ||
tegra | ||
tilcdc | ||
tinydrm | ||
ttm | ||
tve200 | ||
udl | ||
v3d | ||
vc4 | ||
vgem | ||
via | ||
virtio | ||
vkms | ||
vmwgfx | ||
xen | ||
zte | ||
ati_pcigart.c | ||
drm_agpsupport.c | ||
drm_atomic_helper.c | ||
drm_atomic_uapi.c | ||
drm_atomic.c | ||
drm_auth.c | ||
drm_blend.c | ||
drm_bridge.c | ||
drm_bufs.c | ||
drm_cache.c | ||
drm_client.c | ||
drm_color_mgmt.c | ||
drm_connector.c | ||
drm_context.c | ||
drm_crtc_helper_internal.h | ||
drm_crtc_helper.c | ||
drm_crtc_internal.h | ||
drm_crtc.c | ||
drm_debugfs_crc.c | ||
drm_debugfs.c | ||
drm_dma.c | ||
drm_dp_aux_dev.c | ||
drm_dp_cec.c | ||
drm_dp_dual_mode_helper.c | ||
drm_dp_helper.c | ||
drm_dp_mst_topology.c | ||
drm_drv.c | ||
drm_dumb_buffers.c | ||
drm_edid_load.c | ||
drm_edid.c | ||
drm_encoder_slave.c | ||
drm_encoder.c | ||
drm_fb_cma_helper.c | ||
drm_fb_helper.c | ||
drm_file.c | ||
drm_flip_work.c | ||
drm_fourcc.c | ||
drm_framebuffer.c | ||
drm_gem_cma_helper.c | ||
drm_gem_framebuffer_helper.c | ||
drm_gem.c | ||
drm_global.c | ||
drm_hashtab.c | ||
drm_info.c | ||
drm_internal.h | ||
drm_ioc32.c | ||
drm_ioctl.c | ||
drm_irq.c | ||
drm_kms_helper_common.c | ||
drm_lease.c | ||
drm_legacy.h | ||
drm_lock.c | ||
drm_memory.c | ||
drm_mipi_dsi.c | ||
drm_mm.c | ||
drm_mode_config.c | ||
drm_mode_object.c | ||
drm_modes.c | ||
drm_modeset_helper.c | ||
drm_modeset_lock.c | ||
drm_of.c | ||
drm_panel_orientation_quirks.c | ||
drm_panel.c | ||
drm_pci.c | ||
drm_plane_helper.c | ||
drm_plane.c | ||
drm_prime.c | ||
drm_print.c | ||
drm_probe_helper.c | ||
drm_property.c | ||
drm_rect.c | ||
drm_scatter.c | ||
drm_scdc_helper.c | ||
drm_simple_kms_helper.c | ||
drm_syncobj.c | ||
drm_sysfs.c | ||
drm_trace_points.c | ||
drm_trace.h | ||
drm_vblank.c | ||
drm_vm.c | ||
drm_vma_manager.c | ||
drm_writeback.c | ||
Kconfig | ||
Makefile |