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Tomi Valkeinen 56f96cf6eb drm/bridge: sii902x: Fix probing race issue
[ Upstream commit 08ac6f132d ]

A null pointer dereference crash has been observed rarely on TI
platforms using sii9022 bridge:

[   53.271356]  sii902x_get_edid+0x34/0x70 [sii902x]
[   53.276066]  sii902x_bridge_get_edid+0x14/0x20 [sii902x]
[   53.281381]  drm_bridge_get_edid+0x20/0x34 [drm]
[   53.286305]  drm_bridge_connector_get_modes+0x8c/0xcc [drm_kms_helper]
[   53.292955]  drm_helper_probe_single_connector_modes+0x190/0x538 [drm_kms_helper]
[   53.300510]  drm_client_modeset_probe+0x1f0/0xbd4 [drm]
[   53.305958]  __drm_fb_helper_initial_config_and_unlock+0x50/0x510 [drm_kms_helper]
[   53.313611]  drm_fb_helper_initial_config+0x48/0x58 [drm_kms_helper]
[   53.320039]  drm_fbdev_dma_client_hotplug+0x84/0xd4 [drm_dma_helper]
[   53.326401]  drm_client_register+0x5c/0xa0 [drm]
[   53.331216]  drm_fbdev_dma_setup+0xc8/0x13c [drm_dma_helper]
[   53.336881]  tidss_probe+0x128/0x264 [tidss]
[   53.341174]  platform_probe+0x68/0xc4
[   53.344841]  really_probe+0x188/0x3c4
[   53.348501]  __driver_probe_device+0x7c/0x16c
[   53.352854]  driver_probe_device+0x3c/0x10c
[   53.357033]  __device_attach_driver+0xbc/0x158
[   53.361472]  bus_for_each_drv+0x88/0xe8
[   53.365303]  __device_attach+0xa0/0x1b4
[   53.369135]  device_initial_probe+0x14/0x20
[   53.373314]  bus_probe_device+0xb0/0xb4
[   53.377145]  deferred_probe_work_func+0xcc/0x124
[   53.381757]  process_one_work+0x1f0/0x518
[   53.385770]  worker_thread+0x1e8/0x3dc
[   53.389519]  kthread+0x11c/0x120
[   53.392750]  ret_from_fork+0x10/0x20

The issue here is as follows:

- tidss probes, but is deferred as sii902x is still missing.
- sii902x starts probing and enters sii902x_init().
- sii902x calls drm_bridge_add(). Now the sii902x bridge is ready from
  DRM's perspective.
- sii902x calls sii902x_audio_codec_init() and
  platform_device_register_data()
- The registration of the audio platform device causes probing of the
  deferred devices.
- tidss probes, which eventually causes sii902x_bridge_get_edid() to be
  called.
- sii902x_bridge_get_edid() tries to use the i2c to read the edid.
  However, the sii902x driver has not set up the i2c part yet, leading
  to the crash.

Fix this by moving the drm_bridge_add() to the end of the
sii902x_init(), which is also at the very end of sii902x_probe().

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Fixes: 21d808405f ("drm/bridge/sii902x: Fix EDID readback")
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240103-si902x-fixes-v1-1-b9fd3e448411@ideasonboard.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240103-si902x-fixes-v1-1-b9fd3e448411@ideasonboard.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-31 16:19:11 -08:00
arch LoongArch/smp: Call rcutree_report_cpu_starting() earlier 2024-01-31 16:18:57 -08:00
block block: ensure we hold a queue reference when using queue limits 2024-01-25 15:35:57 -08:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: api - Disallow identical driver names 2024-01-31 16:18:49 -08:00
Documentation drm: Allow drivers to indicate the damage helpers to ignore damage clips 2024-01-31 16:19:08 -08:00
drivers drm/bridge: sii902x: Fix probing race issue 2024-01-31 16:19:11 -08:00
fs btrfs: zoned: optimize hint byte for zoned allocator 2024-01-31 16:19:10 -08:00
include serial: core: Provide port lock wrappers 2024-01-31 16:19:10 -08:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 15:35:46 -08:00
io_uring io_uring: adjust defer tw counting 2024-01-25 15:36:00 -08:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel bpf: Add bpf_sock_addr_set_sun_path() to allow writing unix sockaddr from bpf 2024-01-31 16:19:04 -08:00
lib crypto: lib/mpi - Fix unexpected pointer access in mpi_ec_init 2024-01-31 16:18:49 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: migrate: fix getting incorrect page mapping during page migration 2024-01-31 16:19:10 -08:00
net net/bpf: Avoid unused "sin_addr_len" warning when CONFIG_CGROUP_BPF is not set 2024-01-31 16:19:09 -08:00
rust rust: Ignore preserve-most functions 2024-01-25 15:35:41 -08:00
samples vfio/mtty: Overhaul mtty interrupt handling 2024-01-10 17:16:55 +01:00
scripts scripts/get_abi: fix source path leak 2024-01-31 16:18:55 -08:00
security lsm: new security_file_ioctl_compat() hook 2024-01-31 16:18:54 -08:00
sound soundwire: fix initializing sysfs for same devices on different buses 2024-01-31 16:18:47 -08:00
tools selftests: bonding: do not test arp/ns target with mode balance-alb/tlb 2024-01-31 16:19:05 -08:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS Char/Misc driver fixes for 6.6-final 2023-10-28 07:51:27 -10:00
Makefile Linux 6.6.14 2024-01-25 15:36:01 -08:00
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