337cbf3ea8
commit 19b5f3b419a61808ff2713f1f30b8a88fe14ac9b upstream. Mika spotted <4>[17436.705441] general protection fault: 0000 [#1] PREEMPT SMP PTI <4>[17436.705447] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.5.0+ #1 <4>[17436.705449] Hardware name: System manufacturer System Product Name/Z170M-PLUS, BIOS 3805 05/16/2018 <4>[17436.705512] RIP: 0010:__execlists_submission_tasklet+0xc4d/0x16e0 [i915] <4>[17436.705516] Code: c5 4c 8d 60 e0 75 17 e9 8c 07 00 00 49 8b 44 24 20 49 39 c5 4c 8d 60 e0 0f 84 7a 07 00 00 49 8b 5c 24 08 49 8b 87 80 00 00 00 <48> 39 83 d8 fe ff ff 75 d9 48 8b 83 88 fe ff ff a8 01 0f 84 b6 05 <4>[17436.705518] RSP: 0018:ffffc9000012ce80 EFLAGS: 00010083 <4>[17436.705521] RAX: ffff88822ae42000 RBX: 5a5a5a5a5a5a5a5a RCX: dead000000000122 <4>[17436.705523] RDX: ffff88822ae42588 RSI: ffff8881e32a7908 RDI: ffff8881c429fd48 <4>[17436.705525] RBP: ffffc9000012cf00 R08: ffff88822ae42588 R09: 00000000fffffffe <4>[17436.705527] R10: ffff8881c429fb80 R11: 00000000a677cf08 R12: ffff8881c42a0aa8 <4>[17436.705529] R13: ffff8881c429fd38 R14: ffff88822ae42588 R15: ffff8881c429fb80 <4>[17436.705532] FS: 0000000000000000(0000) GS:ffff88822ed00000(0000) knlGS:0000000000000000 <4>[17436.705534] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[17436.705536] CR2: 00007f858c76d000 CR3: 0000000005610003 CR4: 00000000003606e0 <4>[17436.705538] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 <4>[17436.705540] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 <4>[17436.705542] Call Trace: <4>[17436.705545] <IRQ> <4>[17436.705603] execlists_submission_tasklet+0xc0/0x130 [i915] which is us consuming a partially initialised new waiter in defer_requests(). We can prevent this by initialising the i915_dependency prior to making it visible, and since we are using a concurrent list_add/iterator mark them up to the compiler. Fixes: 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing") 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/20200206204915.2636606-2-chris@chris-wilson.co.uk (cherry picked from commit f14f27b1663269a81ed62d3961fe70250a1a0623) Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.