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Filename Latest commit message Latest commit date
Imre Deak c0276de0be drm/i915/dp: Ensure sink rate values are always valid
commit 6c34bd4532a3f39952952ddc102737595729afc4 upstream.

Atm, there are no sink rate values set for DP (vs. eDP) sinks until the
DPCD capabilities are successfully read from the sink. During this time
intel_dp->num_common_rates is 0 which can lead to a

intel_dp->common_rates[-1]    (*)

access, which is an undefined behaviour, in the following cases:

- In intel_dp_sync_state(), if the encoder is enabled without a sink
  connected to the encoder's connector (BIOS enabled a monitor, but the
  user unplugged the monitor until the driver loaded).
- In intel_dp_sync_state() if the encoder is enabled with a sink
  connected, but for some reason the DPCD read has failed.
- In intel_dp_compute_link_config() if modesetting a connector without
  a sink connected on it.
- In intel_dp_compute_link_config() if modesetting a connector with a
  a sink connected on it, but before probing the connector first.

To avoid the (*) access in all the above cases, make sure that the sink
rate table - and hence the common rate table - is always valid, by
setting a default minimum sink rate when registering the connector
before anything could use it.

I also considered setting all the DP link rates by default, so that
modesetting with higher resolution modes also succeeds in the last two
cases above. However in case a sink is not connected that would stop
working after the first modeset, due to the LT fallback logic. So this
would need more work, beyond the scope of this fix.

As I mentioned in the previous patch, I don't think the issue this patch
fixes is user visible, however it is an undefined behaviour by
definition and triggers a BUG() in CONFIG_UBSAN builds, hence CC:stable.

v2: Clear the default sink rates, before initializing these for eDP.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4297
References: https://gitlab.freedesktop.org/drm/intel/-/issues/4298
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211018143417.1452632-1-imre.deak@intel.com
(cherry picked from commit 3f61ef9777c0ab0f03f4af0ed6fd3e5250537a8d)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-26 10:47:22 +01:00
arch s390/kexec: fix memory leak of ipl report buffer 2021-11-26 10:47:21 +01:00
block block: remove inaccurate requeue check 2021-11-17 09:48:31 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation xen/balloon: add late_initcall_sync() for initial ballooning done 2021-11-17 09:48:25 +01:00
drivers drm/i915/dp: Ensure sink rate values are always valid 2021-11-26 10:47:22 +01:00
fs btrfs: fix memory ordering between normal and ordered work functions 2021-11-26 10:47:21 +01:00
include net: virtio_net_hdr_to_skb: count transport header in UFO 2021-11-26 10:47:19 +01:00
init
ipc ipc: WARN if trying to remove ipc object which is absent 2021-11-26 10:47:21 +01:00
kernel tracing/histogram: Do not copy the fixed-size char array field over the field size 2021-11-26 10:47:18 +01:00
lib lib/xz: Validate the value before assigning it to an enum variable 2021-11-17 09:48:31 +01:00
LICENSES
mm mm: kmemleak: slob: respect SLAB_NOLEAKTRACE flag 2021-11-26 10:47:21 +01:00
net cfg80211: call cfg80211_stop_ap when switch from P2P_GO type 2021-11-26 10:47:22 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts leaking_addresses: Always print a trailing newline 2021-11-17 09:48:31 +01:00
security fortify: Explicitly disable Clang support 2021-11-21 13:38:50 +01:00
sound ALSA: gus: fix null pointer dereference on pointer block 2021-11-26 10:47:16 +01:00
tools perf tests: Remove bash construct from record+zstd_comp_decomp.sh 2021-11-26 10:47:18 +01:00
usr
virt KVM: do not shrink halt_poll_ns below grow_start 2021-10-09 14:39:50 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.161 2021-11-21 13:38:51 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.