mainlining shenanigans
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Chris Wilson 26eb4cd6c7 drm/i915: Disable bh around call to tasklet
The guc submission backends expects to only be run from (at least)
softirq context, but during our intel_engine_is_idle() check we would
call into the tasklet to make sure it was flushed. As this could occur
from process context, occasionally we would be caught out using a
wait_for_atomic() not from an atomic context:

[   59.939091] WARN_ON_ONCE((1) && !(preempt_count() != 0))
[   59.939142] WARNING: CPU: 1 PID: 2901 at drivers/gpu/drm/i915/intel_guc_submission.c:615 guc_submission_tasklet+0x784/0xa90 [i915]
[   59.939143] Modules linked in: vgem snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul snd_hda_intel crc32_pclmul snd_hda_codec ghash_clmulni_intel snd_hwdep snd_hda_core e1000e snd_pcm mei_me mei prime_numbers
[   59.939164] CPU: 1 PID: 2901 Comm: gem_exec_schedu Tainted: G     U  W         4.18.0-rc1-g93475d62c730-drmtip_67+ #1
[   59.939165] Hardware name: System manufacturer System Product Name/Z170M-PLUS, BIOS 3610 03/29/2018
[   59.939188] RIP: 0010:guc_submission_tasklet+0x784/0xa90 [i915]
[   59.939189] Code: fc ff ff 80 3d 2f 87 11 00 00 0f 85 80 fb ff ff 48 c7 c6 f8 49 40 c0 48 c7 c7 80 41 3e c0 c6 05 14 87 11 00 01 e8 2c ea d6 d3 <0f> 0b e9 5f fb ff ff 8b 46 38 89 cf 31 c7 83 e7 c0 75 08 39 c1 0f
[   59.939253] RSP: 0018:ffffaafe08a03c10 EFLAGS: 00010286
[   59.939255] RAX: 0000000000000000 RBX: ffff8f9112c246f0 RCX: 0000000000000001
[   59.939256] RDX: 0000000080000001 RSI: ffffffff95086d8e RDI: 00000000ffffffff
[   59.939257] RBP: ffff8f9112c24680 R08: 000000009517be77 R09: 0000000000000000
[   59.939258] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8f9112c24700
[   59.939259] R13: ffff8f9112c24700 R14: 0000000000000000 R15: ffff8f9112c242a8
[   59.939260] FS:  00007fc2cc7e5980(0000) GS:ffff8f9136c40000(0000) knlGS:0000000000000000
[   59.939261] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   59.939262] CR2: 00007fc2cc815040 CR3: 000000021f10e003 CR4: 00000000003606e0
[   59.939263] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   59.939264] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   59.939265] Call Trace:
[   59.939288]  ? intel_engine_is_idle+0x64/0x160 [i915]
[   59.939323]  ? intel_engine_dump+0x638/0x890 [i915]
[   59.939327]  ? seq_printf+0x49/0x70
[   59.939353]  ? i915_engine_info+0xc8/0x100 [i915]
[   59.939356]  ? drm_get_color_range_name+0x20/0x20
[   59.939361]  ? seq_read+0xf1/0x470
[   59.939365]  ? trace_hardirqs_on_caller+0xe0/0x1b0
[   59.939370]  ? full_proxy_read+0x51/0x80
[   59.939389]  ? __vfs_read+0x31/0x170
[   59.939395]  ? do_sys_open+0x13b/0x240
[   59.939398]  ? rcu_read_lock_sched_held+0x6f/0x80
[   59.939401]  ? vfs_read+0x9e/0x140
[   59.939404]  ? ksys_read+0x50/0xc0
[   59.939409]  ? do_syscall_64+0x55/0x190
[   59.939412]  ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
[   59.939420] irq event stamp: 552834
[   59.939422] hardirqs last  enabled at (552833): [<ffffffff940fc74c>] console_unlock+0x3fc/0x600
[   59.939425] hardirqs last disabled at (552834): [<ffffffff94a0111c>] error_entry+0x7c/0x100
[   59.939451] softirqs last  enabled at (552614): [<ffffffffc02e0f53>] i915_request_add+0x2e3/0x7b0 [i915]
[   59.939470] softirqs last disabled at (552604): [<ffffffffc02e0ecb>] i915_request_add+0x25b/0x7b0 [i915]

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106977
Fixes: dd0cf235d8 ("drm/i915: Speed up idle detection by kicking the tasklets")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180620135929.23956-1-chris@chris-wilson.co.uk
2018-06-20 22:22:52 +01:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-29 10:06:05 -07:00
block Revert "blk-mq: remove code for dealing with remapping queue" 2018-04-25 09:49:22 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
Documentation Merge drm/drm-next into drm-intel-next-queued 2018-05-02 12:20:32 +03:00
drivers drm/i915: Disable bh around call to tasklet 2018-06-20 22:22:52 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Fix misc. bugs and a regression for ext4. 2018-04-28 20:07:21 -07:00
include drm/i915/aml: Introducing Amber Lake platform 2018-06-18 10:49:57 -07:00
init Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-15 16:12:35 -07:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-29 09:03:25 -07:00
lib Driver core fixes for 4.17-rc3 2018-04-27 10:12:20 -07:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm x86/pti: Filter at vma->vm_page_prot population 2018-04-25 11:02:51 +02:00
net A CephFS quota follow-up and fixes for two older issues in the 2018-04-27 10:56:29 -07:00
samples Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2018-04-20 08:51:55 -07:00
scripts drm-misc-next for v4.18: 2018-04-30 09:32:43 +10:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-24 17:58:51 -07:00
sound ALSA: dice: fix error path to destroy initialized stream data 2018-04-26 15:24:54 +02:00
tools Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-29 09:36:22 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM fixes for v4.17-rc3 2018-04-27 16:13:31 -07:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS drm-misc-next for v4.18: 2018-04-30 09:32:43 +10:00
Makefile Linux v4.17-rc3 2018-04-29 14:17:42 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.