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Chris Wilson e7004ea4f5 drm/i915/gt: Close race between enable_breadcrumbs and cancel_breadcrumbs
If we enable_breadcrumbs for a request while that request is being
removed from HW; we may see that the request is active as we take the
ce->signal_lock and proceed to attach the request to ce->signals.
However, during unsubmission after marking the request as inactive, we
see that the request has not yet been added to ce->signals and so skip
the removal. Pull the check during cancel_breadcrumbs under the same
spinlock as enabling so that we the two tests are consistent in
enable/cancel.

Otherwise, we may insert a request onto ce->signals that we expect should
not be there:

  intel_context_remove_breadcrumbs:488 GEM_BUG_ON(!__i915_request_is_complete(rq))

While updating, we can note that we are always called with
irqs-disabled, due to the engine->active.lock being held at the single
caller, and so remove the irqsave/restore making it symmetric to
enable_breadcrumbs.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2931
Fixes: c18636f763 ("drm/i915: Remove requirement for holding i915_request.lock for breadcrumbs")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: <stable@vger.kernel.org> # v5.10+
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119162057.31097-1-chris@chris-wilson.co.uk
2021-01-20 09:15:19 +00:00
Documentation Merge tag 'drm-intel-gt-next-2021-01-14' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2021-01-15 15:03:36 +10:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
arch drm-misc-next for v5.12: 2021-01-07 10:46:32 +01:00
block SCSI fixes on 20210101 2021-01-01 12:58:07 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto crypto: aegis128 - avoid spurious references crypto_aegis128_update_simd 2020-12-04 18:16:53 +11:00
drivers drm/i915/gt: Close race between enable_breadcrumbs and cancel_breadcrumbs 2021-01-20 09:15:19 +00:00
fs block-5.11-2021-01-01 2021-01-01 12:49:09 -08:00
include Merge tag 'drm-intel-gt-next-2021-01-14' of git://anongit.freedesktop.org/drm/drm-intel into drm-next 2021-01-15 15:03:36 +10:00
init kasan, arm64: only use kasan_depth for software modes 2020-12-22 12:55:07 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel io_uring-5.11-2021-01-01 2021-01-01 12:29:49 -08:00
lib zlib: move EXPORT_SYMBOL() and MODULE_LICENSE() out of dfltcc_syms.c 2020-12-29 15:36:49 -08:00
mm mm: slub: call account_slab_page() after slab page initialization 2020-12-29 15:36:49 -08:00
net libceph: align session_key and con_secret to 16 bytes 2020-12-28 20:34:33 +01:00
samples ARM: SoC drivers for v5.11 2020-12-16 16:38:41 -08:00
scripts depmod: handle the case of /sbin/depmod without /sbin in PATH 2021-01-01 12:26:39 -08:00
security Provide a fix for the incorrect handling of privilege 2020-12-24 14:08:43 -08:00
sound sound fixes for 5.11-rc1 2020-12-23 15:11:08 -08:00
tools selftests/vm: fix building protection keys test 2020-12-29 15:36:49 -08:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt ARM: 2020-12-20 10:44:05 -08:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.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: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap RDMA 5.11 pull request 2020-12-16 13:42:26 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-11 22:29:38 -08:00
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 drm-misc-next for v5.12: 2021-01-07 13:40:20 +01:00
Makefile Linux 5.11-rc2 2021-01-03 15:55:30 -08:00
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.