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Chris Wilson 89f077ab90 drm/i915: Mark up unlocked update of i915_request.hwsp_seqno
During i915_request_retire() we decouple the i915_request.hwsp_seqno
from the intel_timeline so that it may be freed before the request is
released. However, we need to warn the compiler that the pointer may
update under its nose.

[  171.438899] BUG: KCSAN: data-race in i915_request_await_dma_fence [i915] / i915_request_retire [i915]
[  171.438920]
[  171.438932] write to 0xffff8881e7e28ce0 of 8 bytes by task 148 on cpu 2:
[  171.439174]  i915_request_retire+0x1ea/0x660 [i915]
[  171.439408]  retire_requests+0x7a/0xd0 [i915]
[  171.439640]  engine_retire+0xa1/0xe0 [i915]
[  171.439657]  process_one_work+0x3b1/0x690
[  171.439671]  worker_thread+0x80/0x670
[  171.439685]  kthread+0x19a/0x1e0
[  171.439701]  ret_from_fork+0x1f/0x30
[  171.439721]
[  171.439739] read to 0xffff8881e7e28ce0 of 8 bytes by task 696 on cpu 1:
[  171.439990]  i915_request_await_dma_fence+0x162/0x520 [i915]
[  171.440230]  i915_request_await_object+0x2fe/0x470 [i915]
[  171.440467]  i915_gem_do_execbuffer+0x45dc/0x4c20 [i915]
[  171.440704]  i915_gem_execbuffer2_ioctl+0x2c3/0x580 [i915]
[  171.440722]  drm_ioctl_kernel+0xe4/0x120
[  171.440736]  drm_ioctl+0x297/0x4c7
[  171.440750]  ksys_ioctl+0x89/0xb0
[  171.440766]  __x64_sys_ioctl+0x42/0x60
[  171.440788]  do_syscall_64+0x6e/0x2c0
[  171.440802]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200309110934.868-1-chris@chris-wilson.co.uk
2020-03-09 18:23:59 +00:00
arch Bugfixes and improvements to selftests. On top of this, Mauro converted the 2020-02-16 13:01:42 -08:00
block block-5.6-2020-02-05 2020-02-06 06:15:23 +00:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto s390 updates for 5.6-rc2 2020-02-15 13:10:38 -08:00
Documentation drm/i915: Fix doclinks 2020-03-03 09:56:43 +00:00
drivers drm/i915: Mark up unlocked update of i915_request.hwsp_seqno 2020-03-09 18:23:59 +00:00
fs for-5.6-rc1-tag 2020-02-16 11:43:45 -08:00
include drm/i915: Force DPCD backlight mode on X1 Extreme 2nd Gen 4K AMOLED panel 2020-03-03 20:34:32 -05:00
init Various fixes: 2020-02-11 16:39:18 -08:00
ipc proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
kernel Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-02-15 12:51:22 -08:00
lib Various fixes: 2020-02-11 16:39:18 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
net NFS Client Bugfixes for Linux 5.6-rc2 2020-02-14 14:46:11 -08:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts kbuild: fix mismatch between .version and include/generated/compile.h 2020-02-11 05:18:40 +09:00
security selinux/stable-5.6 PR 20200210 2020-02-10 16:51:35 -08:00
sound ALSA: pcm: Fix double hw_free calls 2020-02-13 16:30:22 +01:00
tools Bugfixes and improvements to selftests. On top of this, Mauro converted the 2020-02-16 13:01:42 -08:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM: Disable preemption in kvm_get_running_vcpu() 2020-02-12 12:19:35 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS open: introduce openat2(2) syscall 2020-01-18 09:19:18 -05:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge drm/drm-next into drm-intel-next-queued 2020-02-25 09:39:23 -08:00
Makefile Linux 5.6-rc2 2020-02-16 13:16:59 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.