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Jason Ekstrand 93a2711cdd Revert "drm/i915: Propagate errors on awaiting already signaled fences" This reverts commit `9e31c1fe45`. Ever since that commit, we've been having issues where a hang in one client can propagate to another. In particular, a hang in an app can propagate to the X server which causes the whole desktop to lock up. Error propagation along fences sound like a good idea, but as your bug shows, surprising consequences, since propagating errors across security boundaries is not a good thing. What we do have is track the hangs on the ctx, and report information to userspace using RESET_STATS. That's how arb_robustness works. Also, if my understanding is still correct, the EIO from execbuf is when your context is banned (because not recoverable or too many hangs). And in all these cases it's up to userspace to figure out what is all impacted and should be reported to the application, that's not on the kernel to guess and automatically propagate. What's more, we're also building more features on top of ctx error reporting with RESET_STATS ioctl: Encrypted buffers use the same, and the userspace fence wait also relies on that mechanism. So it is the path going forward for reporting gpu hangs and resets to userspace. So all together that's why I think we should just bury this idea again as not quite the direction we want to go to, hence why I think the revert is the right option here. For backporters: Please note that you _must_ have a backport of https://lore.kernel.org/dri-devel/20210602164149.391653-2-jason@jlekstrand.net/ for otherwise backporting just this patch opens up a security bug. v2: Augment commit message. Also restore Jason's sob that I accidentally lost. v3: Add a note for backporters Signed-off-by: Jason Ekstrand <jason@jlekstrand.net> Reported-by: Marcin Slusarz <marcin.slusarz@intel.com> Cc: <stable@vger.kernel.org> # v5.6+ Cc: Jason Ekstrand <jason.ekstrand@intel.com> Cc: Marcin Slusarz <marcin.slusarz@intel.com> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3080 Fixes: `9e31c1fe45` ("drm/i915: Propagate errors on awaiting already signaled fences") Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210714193419.1459723-3-jason@jlekstrand.net		2021-07-16 21:47:00 +02:00
arch	Two fixes:	2021-07-11 11:17:57 -07:00
block	block-5.14-2021-07-08	2021-07-09 12:05:33 -07:00
certs	Kbuild updates for v5.13 (2nd)	2021-05-08 10:00:11 -07:00
crypto	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2021-07-09 11:00:44 -07:00
Documentation	drm/i915: Fix missing docbook chapters for i915 uapi.	2021-07-16 10:52:59 +02:00
drivers	Revert "drm/i915: Propagate errors on awaiting already signaled fences"	2021-07-16 21:47:00 +02:00
fs	13 cifs/smb3 fixes. Most are to address minor issues pointed out by Coverity. Also includes a packet signing enhancement and mount improvement	2021-07-10 12:04:58 -07:00
include	drm/i915/uapi: convert drm_i915_gem_set_domain to kernel doc	2021-07-14 09:03:16 +01:00
init	Kbuild updates for v5.14	2021-07-10 11:01:38 -07:00
ipc	Merge branch 'akpm' (patches from Andrew)	2021-07-02 12:08:10 -07:00
kernel	Two fixes:	2021-07-11 11:17:57 -07:00
lib	mm/page_alloc: Revert pahole zero-sized workaround	2021-07-10 16:09:39 -07:00
LICENSES	LICENSES: Add the CC-BY-4.0 license	2020-12-08 10:33:27 -07:00
mm	mm/rmap: try_to_migrate() skip zone_device !device_private	2021-07-11 15:05:15 -07:00
net	We have new filesystem client metrics for reporting I/O sizes from	2021-07-09 09:52:13 -07:00
samples	VFIO update for v5.14-rc1	2021-07-03 11:49:33 -07:00
scripts	Kbuild updates for v5.14	2021-07-10 11:01:38 -07:00
security	asm-generic/unaligned: Unify asm/unaligned.h around struct helper	2021-07-02 12:43:40 -07:00
sound	sound fixes for 5.14-rc1	2021-07-09 11:40:26 -07:00
tools	perf tools changes for v5.14: 2nd batch	2021-07-11 10:54:24 -07:00
usr	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
virt	Merge branch 'akpm' (patches from Andrew)	2021-06-29 17:29:11 -07:00
.clang-format	clang-format: Update with the latest for_each macro list	2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	m68k updates for v5.14	2021-06-28 14:01:03 -07:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: move Murali Karicheri to credits	2021-04-29 15:47:30 -07:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	SCSI misc on 20210711	2021-07-11 10:59:53 -07:00
Makefile	Linux 5.14-rc1	2021-07-11 15:07:40 -07:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

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.