Pull the GT clock information [used to derive CS timestamps and PM
interval] under the GT so that is it local to the users. In doing so, we
consolidate the two references for the same information, of which the
runtime-info took note of a potential clock source override and scaling
factors.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201223122359.22562-2-chris@chris-wilson.co.uk

Instead of printing out the internal engine mask, which can change between
kernel versions making it difficult to map to actual engines, present a
bitmask of hanging engines ABI classes. For example:

  [drm] GPU HANG: ecode 9:8:24dffffd, in gem_exec_schedu [1334]

Engine ABI class is useful to quickly categorize render vs media etc hangs
in bug reports. Considering virtual engine even more so than the current
scheme.

v2:
 * Do not re-order fields. (Chris)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105113842.1395391-1-tvrtko.ursulin@linux.intel.com

Between events which trigger engine and GPU resets and capturing the error
state we lose information on which engine triggered the reset. Improve
this by passing in the hung engine mask down to error capture.

Result is that the list of engines in user visible "GPU HANG: ecode
<gen>:<engines>:<ecode>, <process>" is now a list of hanging and not just
active engines. Most importantly the displayed process is now the one
which was actually hung.

v2:
 * Stub prototype. (Chris)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201104134743.916027-1-tvrtko.ursulin@linux.intel.com

During error capture, we need to take a reference to the vma from before
the reset in order to catpure the contents of the vma later. Currently
we are using both an active reference and a kref, but due to nature of
the i915_vma reference handling, that kref is on the vma->obj and not
the vma itself. This means the vma may be destroyed as soon as it is
idle, that is in between the i915_active_release(&vma->active) and the
i915_vma_put(vma):

<3> [197.866181] BUG: KASAN: use-after-free in intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<3> [197.866339] Read of size 8 at addr ffff8881258cb800 by task gem_exec_captur/1041
<3> [197.866467]
<4> [197.866512] CPU: 2 PID: 1041 Comm: gem_exec_captur Not tainted 5.9.0-g5e4234f97efba-kasan_200+ #1
<4> [197.866521] Hardware name: Intel Corp. Broxton P/Apollolake RVP1A, BIOS APLKRVPA.X64.0150.B11.1608081044 08/08/2016
<4> [197.866530] Call Trace:
<4> [197.866549]  dump_stack+0x99/0xd0
<4> [197.866760]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.866783]  print_address_description.constprop.8+0x3e/0x60
<4> [197.866797]  ? kmsg_dump_rewind_nolock+0xd4/0xd4
<4> [197.866819]  ? lockdep_hardirqs_off+0xd4/0x120
<4> [197.867037]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867249]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867270]  kasan_report.cold.10+0x1f/0x37
<4> [197.867492]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867710]  intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867949]  i915_gpu_coredump.part.29+0x150/0x7b0 [i915]
<4> [197.868186]  i915_capture_error_state+0x5e/0xc0 [i915]
<4> [197.868396]  intel_gt_handle_error+0x6eb/0xa20 [i915]
<4> [197.868624]  ? intel_gt_reset_global+0x370/0x370 [i915]
<4> [197.868644]  ? check_flags+0x50/0x50
<4> [197.868662]  ? __lock_acquire+0xd59/0x6b00
<4> [197.868678]  ? register_lock_class+0x1ad0/0x1ad0
<4> [197.868944]  i915_wedged_set+0xcf/0x1b0 [i915]
<4> [197.869147]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869371]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869398]  simple_attr_write+0x153/0x1c0
<4> [197.869428]  full_proxy_write+0xee/0x180
<4> [197.869442]  ? __sb_start_write+0x1f3/0x310
<4> [197.869465]  vfs_write+0x1a3/0x640
<4> [197.869492]  ksys_write+0xec/0x1c0
<4> [197.869507]  ? __ia32_sys_read+0xa0/0xa0
<4> [197.869525]  ? lockdep_hardirqs_on_prepare+0x32b/0x4e0
<4> [197.869541]  ? syscall_enter_from_user_mode+0x1c/0x50
<4> [197.869566]  do_syscall_64+0x33/0x80
<4> [197.869579]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<4> [197.869590] RIP: 0033:0x7fd8b7aee281
<4> [197.869604] Code: c3 0f 1f 84 00 00 00 00 00 48 8b 05 59 8d 20 00 c3 0f 1f 84 00 00 00 00 00 8b 05 8a d1 20 00 85 c0 75 16 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 57 f3 c3 0f 1f 44 00 00 41 54 55 49 89 d4 53
<4> [197.869613] RSP: 002b:00007ffea3b72008 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4> [197.869625] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd8b7aee281
<4> [197.869633] RDX: 0000000000000002 RSI: 00007fd8b81a82e7 RDI: 000000000000000d
<4> [197.869641] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000034
<4> [197.869650] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8b81a82e7
<4> [197.869658] R13: 000000000000000d R14: 0000000000000000 R15: 0000000000000000
<3> [197.869707]
<3> [197.869757] Allocated by task 1041:
<4> [197.869833]  kasan_save_stack+0x19/0x40
<4> [197.869843]  __kasan_kmalloc.constprop.5+0xc1/0xd0
<4> [197.869853]  kmem_cache_alloc+0x106/0x8e0
<4> [197.870059]  i915_vma_instance+0x212/0x1930 [i915]
<4> [197.870270]  eb_lookup_vmas+0xe06/0x1d10 [i915]
<4> [197.870475]  i915_gem_do_execbuffer+0x131d/0x4080 [i915]
<4> [197.870682]  i915_gem_execbuffer2_ioctl+0x103/0x5d0 [i915]
<4> [197.870701]  drm_ioctl_kernel+0x1d2/0x270
<4> [197.870710]  drm_ioctl+0x40d/0x85c
<4> [197.870721]  __x64_sys_ioctl+0x10d/0x170
<4> [197.870731]  do_syscall_64+0x33/0x80
<4> [197.870740]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<3> [197.870748]
<3> [197.870798] Freed by task 22:
<4> [197.870865]  kasan_save_stack+0x19/0x40
<4> [197.870875]  kasan_set_track+0x1c/0x30
<4> [197.870884]  kasan_set_free_info+0x1b/0x30
<4> [197.870894]  __kasan_slab_free+0x111/0x160
<4> [197.870903]  kmem_cache_free+0xcd/0x710
<4> [197.871109]  i915_vma_parked+0x618/0x800 [i915]
<4> [197.871307]  __gt_park+0xdb/0x1e0 [i915]
<4> [197.871501]  ____intel_wakeref_put_last+0xb1/0x190 [i915]
<4> [197.871516]  process_one_work+0x8dc/0x15d0
<4> [197.871525]  worker_thread+0x82/0xb30
<4> [197.871535]  kthread+0x36d/0x440
<4> [197.871545]  ret_from_fork+0x22/0x30
<3> [197.871553]
<3> [197.871602] The buggy address belongs to the object at ffff8881258cb740
 which belongs to the cache i915_vma of size 968

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2553
Fixes: 2850748e ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201016092527.29039-1-chris@chris-wilson.co.uk
(cherry picked from commit 178536b8)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

During error capture, we need to take a reference to the vma from before
the reset in order to catpure the contents of the vma later. Currently
we are using both an active reference and a kref, but due to nature of
the i915_vma reference handling, that kref is on the vma->obj and not
the vma itself. This means the vma may be destroyed as soon as it is
idle, that is in between the i915_active_release(&vma->active) and the
i915_vma_put(vma):

<3> [197.866181] BUG: KASAN: use-after-free in intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<3> [197.866339] Read of size 8 at addr ffff8881258cb800 by task gem_exec_captur/1041
<3> [197.866467]
<4> [197.866512] CPU: 2 PID: 1041 Comm: gem_exec_captur Not tainted 5.9.0-g5e4234f97efba-kasan_200+ #1
<4> [197.866521] Hardware name: Intel Corp. Broxton P/Apollolake RVP1A, BIOS APLKRVPA.X64.0150.B11.1608081044 08/08/2016
<4> [197.866530] Call Trace:
<4> [197.866549]  dump_stack+0x99/0xd0
<4> [197.866760]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.866783]  print_address_description.constprop.8+0x3e/0x60
<4> [197.866797]  ? kmsg_dump_rewind_nolock+0xd4/0xd4
<4> [197.866819]  ? lockdep_hardirqs_off+0xd4/0x120
<4> [197.867037]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867249]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867270]  kasan_report.cold.10+0x1f/0x37
<4> [197.867492]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867710]  intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867949]  i915_gpu_coredump.part.29+0x150/0x7b0 [i915]
<4> [197.868186]  i915_capture_error_state+0x5e/0xc0 [i915]
<4> [197.868396]  intel_gt_handle_error+0x6eb/0xa20 [i915]
<4> [197.868624]  ? intel_gt_reset_global+0x370/0x370 [i915]
<4> [197.868644]  ? check_flags+0x50/0x50
<4> [197.868662]  ? __lock_acquire+0xd59/0x6b00
<4> [197.868678]  ? register_lock_class+0x1ad0/0x1ad0
<4> [197.868944]  i915_wedged_set+0xcf/0x1b0 [i915]
<4> [197.869147]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869371]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869398]  simple_attr_write+0x153/0x1c0
<4> [197.869428]  full_proxy_write+0xee/0x180
<4> [197.869442]  ? __sb_start_write+0x1f3/0x310
<4> [197.869465]  vfs_write+0x1a3/0x640
<4> [197.869492]  ksys_write+0xec/0x1c0
<4> [197.869507]  ? __ia32_sys_read+0xa0/0xa0
<4> [197.869525]  ? lockdep_hardirqs_on_prepare+0x32b/0x4e0
<4> [197.869541]  ? syscall_enter_from_user_mode+0x1c/0x50
<4> [197.869566]  do_syscall_64+0x33/0x80
<4> [197.869579]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<4> [197.869590] RIP: 0033:0x7fd8b7aee281
<4> [197.869604] Code: c3 0f 1f 84 00 00 00 00 00 48 8b 05 59 8d 20 00 c3 0f 1f 84 00 00 00 00 00 8b 05 8a d1 20 00 85 c0 75 16 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 57 f3 c3 0f 1f 44 00 00 41 54 55 49 89 d4 53
<4> [197.869613] RSP: 002b:00007ffea3b72008 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4> [197.869625] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd8b7aee281
<4> [197.869633] RDX: 0000000000000002 RSI: 00007fd8b81a82e7 RDI: 000000000000000d
<4> [197.869641] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000034
<4> [197.869650] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8b81a82e7
<4> [197.869658] R13: 000000000000000d R14: 0000000000000000 R15: 0000000000000000
<3> [197.869707]
<3> [197.869757] Allocated by task 1041:
<4> [197.869833]  kasan_save_stack+0x19/0x40
<4> [197.869843]  __kasan_kmalloc.constprop.5+0xc1/0xd0
<4> [197.869853]  kmem_cache_alloc+0x106/0x8e0
<4> [197.870059]  i915_vma_instance+0x212/0x1930 [i915]
<4> [197.870270]  eb_lookup_vmas+0xe06/0x1d10 [i915]
<4> [197.870475]  i915_gem_do_execbuffer+0x131d/0x4080 [i915]
<4> [197.870682]  i915_gem_execbuffer2_ioctl+0x103/0x5d0 [i915]
<4> [197.870701]  drm_ioctl_kernel+0x1d2/0x270
<4> [197.870710]  drm_ioctl+0x40d/0x85c
<4> [197.870721]  __x64_sys_ioctl+0x10d/0x170
<4> [197.870731]  do_syscall_64+0x33/0x80
<4> [197.870740]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<3> [197.870748]
<3> [197.870798] Freed by task 22:
<4> [197.870865]  kasan_save_stack+0x19/0x40
<4> [197.870875]  kasan_set_track+0x1c/0x30
<4> [197.870884]  kasan_set_free_info+0x1b/0x30
<4> [197.870894]  __kasan_slab_free+0x111/0x160
<4> [197.870903]  kmem_cache_free+0xcd/0x710
<4> [197.871109]  i915_vma_parked+0x618/0x800 [i915]
<4> [197.871307]  __gt_park+0xdb/0x1e0 [i915]
<4> [197.871501]  ____intel_wakeref_put_last+0xb1/0x190 [i915]
<4> [197.871516]  process_one_work+0x8dc/0x15d0
<4> [197.871525]  worker_thread+0x82/0xb30
<4> [197.871535]  kthread+0x36d/0x440
<4> [197.871545]  ret_from_fork+0x22/0x30
<3> [197.871553]
<3> [197.871602] The buggy address belongs to the object at ffff8881258cb740
 which belongs to the cache i915_vma of size 968

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2553
Fixes: 2850748e ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201016092527.29039-1-chris@chris-wilson.co.uk

As the error capture will compress user buffers as directed to by the
user, it can take an arbitrary amount of time and space. Break up the
compression loops with a call to cond_resched(), that will allow other
processes to schedule (avoiding the soft lockups) and also serve as a
warning should we try to make this loop atomic in the future.

Testcase: igt/gem_exec_capture/many-*
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200916090059.3189-2-chris@chris-wilson.co.uk
(cherry picked from commit 293f43c8)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

Shrink the hold time for the error capture mutex to just around the
acquire/release of the PTE used for reading back the object via the
Global GTT. For platforms that do not need the GGTT read back, we can
skip the mutex entirely and allow concurrent error capture. Where we do
use the GGTT, by restricting the hold time around the slow readback and
compression, we are more resilient against softlockups (khungtaskd) as
the heartbeat may well also trigger an error while the first is on
going, and this allows the heartbeat reset to skip past the capture and
not be stalled.

Testcase: igt/gem_exec_capture/many-*
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200916090059.3189-3-chris@chris-wilson.co.uk

As the error capture will compress user buffers as directed to by the
user, it can take an arbitrary amount of time and space. Break up the
compression loops with a call to cond_resched(), that will allow other
processes to schedule (avoiding the soft lockups) and also serve as a
warning should we try to make this loop atomic in the future.

Testcase: igt/gem_exec_capture/many-*
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200916090059.3189-2-chris@chris-wilson.co.uk

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

We try not to assume that we captured any information, and so have to
check that error->gt exists before reporting. This check was missed in
err_print_capabilities, so lets break up the capability info and push it
into the GT dump.

We are still a long way from yamlifying this output!
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Fixes: 792592e7 ("drm/i915: Move the engine mask to intel_gt_info")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200710193239.5419-1-chris@chris-wilson.co.uk

SSEUs are a GT capability, so track them under gt_info.
Signed-off-by: NVenkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com>
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708003952.21831-8-daniele.ceraolospurio@intel.com

Keep all the SSEU code in the relevant file. The code has also been
updated to use intel_gt instead of dev_priv.

Based on an original patch by Sandeep.
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708003952.21831-7-daniele.ceraolospurio@intel.com

Since the engines belong to the GT, move the runtime-updated list of
available engines to the intel_gt struct. The original mask has been
renamed to indicate it contains the maximum engine list that can be
found on a matching device.

In preparation for other info being moved to the gt in follow up patches
(sseu), introduce an intel_gt_info structure to group all gt-related
runtime info.

v2: s/max_engine_mask/platform_engine_mask (tvrtko), fix selftest
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> #v1
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708003952.21831-5-daniele.ceraolospurio@intel.com

Start using device specific parameters instead of module parameters for
most things. The module parameters become the immutable initial values
for i915 parameters. The device specific parameters in i915->params
start life as a copy of i915_modparams. Any later changes are only
reflected in the debugfs.

The stragglers are:

* i915.force_probe and i915.modeset. Needed before dev_priv is
  available. This is fine because the parameters are read-only and never
  modified.

* i915.verbose_state_checks. Passing dev_priv to I915_STATE_WARN and
  I915_STATE_WARN_ON would result in massive and ugly churn. This is
  handled by not exposing the parameter via debugfs, and leaving the
  parameter writable in sysfs. This may be fixed up in follow-up work.

* i915.inject_probe_failure. Only makes sense in terms of the module,
  not the device. This is handled by not exposing the parameter via
  debugfs.

v2: Fix uc i915 lookup code (Michał Winiarski)

Cc: Juha-Pekka Heikkilä <juha-pekka.heikkila@intel.com>
Cc: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: NMichał Winiarski <michal.winiarski@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200618150402.14022-1-jani.nikula@intel.com

Once the intel_context is closed, the GEM context may be freed and so
the link from intel_context.gem_context is invalid.

<3>[  219.782944] BUG: KASAN: use-after-free in intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<3>[  219.782996] Read of size 8 at addr ffff8881d7dff0b8 by task kworker/0:1/12

<4>[  219.783052] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G     U            5.7.0-rc2-g1f3ffd7683d54-kasan_118+ #1
<4>[  219.783055] Hardware name: System manufacturer System Product Name/Z170 PRO GAMING, BIOS 3402 04/26/2017
<4>[  219.783105] Workqueue: events heartbeat [i915]
<4>[  219.783109] Call Trace:
<4>[  219.783113]  <IRQ>
<4>[  219.783119]  dump_stack+0x96/0xdb
<4>[  219.783177]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783182]  print_address_description.constprop.6+0x16/0x310
<4>[  219.783239]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783295]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783300]  __kasan_report+0x137/0x190
<4>[  219.783359]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783366]  kasan_report+0x32/0x50
<4>[  219.783426]  intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783481]  execlists_reset+0x39c/0x13d0 [i915]
<4>[  219.783494]  ? mark_held_locks+0x9e/0xe0
<4>[  219.783546]  ? execlists_hold+0xfc0/0xfc0 [i915]
<4>[  219.783551]  ? lockdep_hardirqs_on+0x348/0x5f0
<4>[  219.783557]  ? _raw_spin_unlock_irqrestore+0x34/0x60
<4>[  219.783606]  ? execlists_submission_tasklet+0x118/0x3a0 [i915]
<4>[  219.783615]  tasklet_action_common.isra.14+0x13b/0x410
<4>[  219.783623]  ? __do_softirq+0x1e4/0x9a7
<4>[  219.783630]  __do_softirq+0x226/0x9a7
<4>[  219.783643]  do_softirq_own_stack+0x2a/0x40
<4>[  219.783647]  </IRQ>
<4>[  219.783692]  ? heartbeat+0x3e2/0x10f0 [i915]
<4>[  219.783696]  do_softirq.part.13+0x49/0x50
<4>[  219.783700]  __local_bh_enable_ip+0x1a2/0x1e0
<4>[  219.783748]  heartbeat+0x409/0x10f0 [i915]
<4>[  219.783801]  ? __live_idle_pulse+0x9f0/0x9f0 [i915]
<4>[  219.783806]  ? lock_acquire+0x1ac/0x8a0
<4>[  219.783811]  ? process_one_work+0x811/0x1870
<4>[  219.783827]  ? rcu_read_lock_sched_held+0x9c/0xd0
<4>[  219.783832]  ? rcu_read_lock_bh_held+0xb0/0xb0
<4>[  219.783836]  ? _raw_spin_unlock_irq+0x1f/0x40
<4>[  219.783845]  process_one_work+0x8ca/0x1870
<4>[  219.783848]  ? lock_acquire+0x1ac/0x8a0
<4>[  219.783852]  ? worker_thread+0x1d0/0xb80
<4>[  219.783864]  ? pwq_dec_nr_in_flight+0x2c0/0x2c0
<4>[  219.783870]  ? do_raw_spin_lock+0x129/0x290
<4>[  219.783886]  worker_thread+0x82/0xb80
<4>[  219.783895]  ? __kthread_parkme+0xaf/0x1b0
<4>[  219.783902]  ? process_one_work+0x1870/0x1870
<4>[  219.783906]  kthread+0x34e/0x420
<4>[  219.783911]  ? kthread_create_on_node+0xc0/0xc0
<4>[  219.783918]  ret_from_fork+0x3a/0x50

<3>[  219.783950] Allocated by task 1264:
<4>[  219.783975]  save_stack+0x19/0x40
<4>[  219.783978]  __kasan_kmalloc.constprop.3+0xa0/0xd0
<4>[  219.784029]  i915_gem_create_context+0xa2/0xab8 [i915]
<4>[  219.784081]  i915_gem_context_create_ioctl+0x1fa/0x450 [i915]
<4>[  219.784085]  drm_ioctl_kernel+0x1d8/0x270
<4>[  219.784088]  drm_ioctl+0x676/0x930
<4>[  219.784092]  ksys_ioctl+0xb7/0xe0
<4>[  219.784096]  __x64_sys_ioctl+0x6a/0xb0
<4>[  219.784100]  do_syscall_64+0x94/0x530
<4>[  219.784103]  entry_SYSCALL_64_after_hwframe+0x49/0xb3

<3>[  219.784120] Freed by task 12:
<4>[  219.784141]  save_stack+0x19/0x40
<4>[  219.784145]  __kasan_slab_free+0x130/0x180
<4>[  219.784148]  kmem_cache_free_bulk+0x1bd/0x500
<4>[  219.784152]  kfree_rcu_work+0x1d8/0x890
<4>[  219.784155]  process_one_work+0x8ca/0x1870
<4>[  219.784158]  worker_thread+0x82/0xb80
<4>[  219.784162]  kthread+0x34e/0x420
<4>[  219.784165]  ret_from_fork+0x3a/0x50

Fixes: 2e46a2a0 ("drm/i915: Use explicit flag to mark unreachable intel_context")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAkeem G Abodunrin <akeem.g.abodunrin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428090255.10035-1-chris@chris-wilson.co.uk
(cherry picked from commit 24aac336)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

We need to keep the default context state around to instantiate new
contexts (aka golden rendercontext), and we also keep it pinned while
the engine is active so that we can quickly reset a hanging context.
However, the default contexts are large enough to merit keeping in
swappable memory as opposed to kernel memory, so we store them inside
shmemfs. Currently, we use the normal GEM objects to create the default
context image, but we can throw away all but the shmemfs file.

This greatly simplifies the tricky power management code which wants to
run underneath the normal GT locking, and we definitely do not want to
use any high level objects that may appear to recurse back into the GT.
Though perhaps the primary advantage of the complex GEM object is that
we aggressively cache the mapping, but here we are recreating the
vm_area everytime time we unpark. At the worst, we add a lightweight
cache, but first find a microbenchmark that is impacted.

Having started to create some utility functions to make working with
shmemfs objects easier, we can start putting them to wider use, where
GEM objects are overkill, such as storing persistent error state.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429172429.6054-1-chris@chris-wilson.co.uk

Once the intel_context is closed, the GEM context may be freed and so
the link from intel_context.gem_context is invalid.

<3>[  219.782944] BUG: KASAN: use-after-free in intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<3>[  219.782996] Read of size 8 at addr ffff8881d7dff0b8 by task kworker/0:1/12

<4>[  219.783052] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G     U            5.7.0-rc2-g1f3ffd7683d54-kasan_118+ #1
<4>[  219.783055] Hardware name: System manufacturer System Product Name/Z170 PRO GAMING, BIOS 3402 04/26/2017
<4>[  219.783105] Workqueue: events heartbeat [i915]
<4>[  219.783109] Call Trace:
<4>[  219.783113]  <IRQ>
<4>[  219.783119]  dump_stack+0x96/0xdb
<4>[  219.783177]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783182]  print_address_description.constprop.6+0x16/0x310
<4>[  219.783239]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783295]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783300]  __kasan_report+0x137/0x190
<4>[  219.783359]  ? intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783366]  kasan_report+0x32/0x50
<4>[  219.783426]  intel_engine_coredump_alloc+0x1bc3/0x2250 [i915]
<4>[  219.783481]  execlists_reset+0x39c/0x13d0 [i915]
<4>[  219.783494]  ? mark_held_locks+0x9e/0xe0
<4>[  219.783546]  ? execlists_hold+0xfc0/0xfc0 [i915]
<4>[  219.783551]  ? lockdep_hardirqs_on+0x348/0x5f0
<4>[  219.783557]  ? _raw_spin_unlock_irqrestore+0x34/0x60
<4>[  219.783606]  ? execlists_submission_tasklet+0x118/0x3a0 [i915]
<4>[  219.783615]  tasklet_action_common.isra.14+0x13b/0x410
<4>[  219.783623]  ? __do_softirq+0x1e4/0x9a7
<4>[  219.783630]  __do_softirq+0x226/0x9a7
<4>[  219.783643]  do_softirq_own_stack+0x2a/0x40
<4>[  219.783647]  </IRQ>
<4>[  219.783692]  ? heartbeat+0x3e2/0x10f0 [i915]
<4>[  219.783696]  do_softirq.part.13+0x49/0x50
<4>[  219.783700]  __local_bh_enable_ip+0x1a2/0x1e0
<4>[  219.783748]  heartbeat+0x409/0x10f0 [i915]
<4>[  219.783801]  ? __live_idle_pulse+0x9f0/0x9f0 [i915]
<4>[  219.783806]  ? lock_acquire+0x1ac/0x8a0
<4>[  219.783811]  ? process_one_work+0x811/0x1870
<4>[  219.783827]  ? rcu_read_lock_sched_held+0x9c/0xd0
<4>[  219.783832]  ? rcu_read_lock_bh_held+0xb0/0xb0
<4>[  219.783836]  ? _raw_spin_unlock_irq+0x1f/0x40
<4>[  219.783845]  process_one_work+0x8ca/0x1870
<4>[  219.783848]  ? lock_acquire+0x1ac/0x8a0
<4>[  219.783852]  ? worker_thread+0x1d0/0xb80
<4>[  219.783864]  ? pwq_dec_nr_in_flight+0x2c0/0x2c0
<4>[  219.783870]  ? do_raw_spin_lock+0x129/0x290
<4>[  219.783886]  worker_thread+0x82/0xb80
<4>[  219.783895]  ? __kthread_parkme+0xaf/0x1b0
<4>[  219.783902]  ? process_one_work+0x1870/0x1870
<4>[  219.783906]  kthread+0x34e/0x420
<4>[  219.783911]  ? kthread_create_on_node+0xc0/0xc0
<4>[  219.783918]  ret_from_fork+0x3a/0x50

<3>[  219.783950] Allocated by task 1264:
<4>[  219.783975]  save_stack+0x19/0x40
<4>[  219.783978]  __kasan_kmalloc.constprop.3+0xa0/0xd0
<4>[  219.784029]  i915_gem_create_context+0xa2/0xab8 [i915]
<4>[  219.784081]  i915_gem_context_create_ioctl+0x1fa/0x450 [i915]
<4>[  219.784085]  drm_ioctl_kernel+0x1d8/0x270
<4>[  219.784088]  drm_ioctl+0x676/0x930
<4>[  219.784092]  ksys_ioctl+0xb7/0xe0
<4>[  219.784096]  __x64_sys_ioctl+0x6a/0xb0
<4>[  219.784100]  do_syscall_64+0x94/0x530
<4>[  219.784103]  entry_SYSCALL_64_after_hwframe+0x49/0xb3

<3>[  219.784120] Freed by task 12:
<4>[  219.784141]  save_stack+0x19/0x40
<4>[  219.784145]  __kasan_slab_free+0x130/0x180
<4>[  219.784148]  kmem_cache_free_bulk+0x1bd/0x500
<4>[  219.784152]  kfree_rcu_work+0x1d8/0x890
<4>[  219.784155]  process_one_work+0x8ca/0x1870
<4>[  219.784158]  worker_thread+0x82/0xb80
<4>[  219.784162]  kthread+0x34e/0x420
<4>[  219.784165]  ret_from_fork+0x3a/0x50

Fixes: 2e46a2a0 ("drm/i915: Use explicit flag to mark unreachable intel_context")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAkeem G Abodunrin <akeem.g.abodunrin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428090255.10035-1-chris@chris-wilson.co.uk

We only hold the active spinlock while dumping the error state, and this
does not prevent another thread from retiring the request -- as it is
quite possible that despite us capturing the current state, the GPU has
completed the request. As such, it is dangerous to dereference state
below the request as it may already be freed, and the simplest way to
avoid the danger is not include it in the error state.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1788Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424191410.27570-1-chris@chris-wilson.co.uk

Prefer struct drm_device based logging over struct device based logging.

No functional changes.

Cc: Wambui Karuga <wambui.karugax@gmail.com>
Reviewed-by: NWambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200402114819.17232-11-jani.nikula@intel.com

We've moved from bugzilla to gitlab.

Cc: stable@vger.kernel.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200212160434.6437-2-jani.nikula@intel.com
(cherry picked from commit ddae4d7a)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

We've moved from bugzilla to gitlab.

Cc: stable@vger.kernel.org
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200212160434.6437-2-jani.nikula@intel.com

GPU saves accumulated context runtime (in CS timestamp units) in PPHWSP
which will be useful for us in cases when we are not able to track context
busyness ourselves (like with GuC). Keep a copy of this in struct
intel_context from where it can be easily read even if the context is not
pinned.

v2:
 (Chris)
 * Do not store pphwsp address in intel_context.
 * Log CS wrap-around.
 * Simplify calculation by relying on integer wraparound.
v3:
 * Include total/avg in traces and error state for debugging
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200216133620.394962-1-chris@chris-wilson.co.uk

The DMC firmware is about display. Move the handling under display. No
functional changes.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200211161451.6867-1-jani.nikula@intel.com

For a simulated preemption reset, we don't populate the request and so
do not fill in the guilty context name.

[   79.991294] i915 0000:00:02.0: GPU HANG: ecode 9:1:e757fefe, in  [0]

Just don't mention the empty string in the logs!

Fixes: 742379c0 ("drm/i915: Start chopping up the GPU error capture")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200121132107.267709-1-chris@chris-wilson.co.uk
(cherry picked from commit 29baf3ae)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Could be helpful for debugging purposes.
Signed-off-by: NLionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200129181638.1528150-1-lionel.g.landwerlin@intel.com

Now that we have offline error capture and can reset an engine from
inside an atomic context while also preserving the GPU state for
post-mortem analysis, it is time to handle error interrupts thrown by
the command parser.

This provides a much, much faster mechanism for us to detect known
problems than using heartbeats/hangchecks, and also provides a mechanism
for when those are disabled. However, it is limited to problems the HW
can detect in the CS and so not a complete solution for detecting lockups.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128204318.4182039-2-chris@chris-wilson.co.uk

We don't want to report errors on the internal contexts to userspace,
suppressing their own, so treat them as simulated errors. These mostly
arise inside selftests and so are simulated anyway. For the rest, we can
rely on the normal debug channels in CI.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128113426.3711294-1-chris@chris-wilson.co.uk

For a simulated preemption reset, we don't populate the request and so
do not fill in the guilty context name.

[   79.991294] i915 0000:00:02.0: GPU HANG: ecode 9:1:e757fefe, in  [0]

Just don't mention the empty string in the logs!

Fixes: 742379c0 ("drm/i915: Start chopping up the GPU error capture")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200121132107.267709-1-chris@chris-wilson.co.uk

The list of requests from after the hang tells little about the hang
itself, only how busy userspace was after the fact. As it pertains
nothing to the HW state, drop it from the error state.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200110123059.1348712-4-chris@chris-wilson.co.uk

The shadow ring regs (ring->head, ring->tail) are meaningless in the
post-mortem dump as they do not related to anything on HW. Remove them
from the coredump.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200110123059.1348712-3-chris@chris-wilson.co.uk

While this is technically the batch as executed by the HW (in part at
least), it is confusing, and only used for a minority of gen.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200110123059.1348712-2-chris@chris-wilson.co.uk

In the near future, we will want to start a GPU error capture from a new
context, from inside the softirq region of a forced preemption. To do
so requires us to break up the monolithic error capture to provide new
entry points with finer control; in particular focusing on one
engine/gt, and being able to compose an error state from little pieces
of HW capture.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200110123059.1348712-1-chris@chris-wilson.co.uk

The only protection for intel_context.gem_cotext is granted by RCU, so
annotate it as a rcu protected pointer and carefully dereference it in
the few occasions we need to use it.

Fixes: 9f3ccd40 ("drm/i915: Drop GEM context as a direct link from i915_request")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191222233558.2201901-1-chris@chris-wilson.co.uk

Keep the intel_context as being the primary state for i915_request, with
the GEM context a backpointer from the low level state for the rarer
cases we need client information. Our goal is to remove such references
to clients from the backend, and leave the HW submission agnostic to
client interfaces and self-contained.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191220101230.256839-1-chris@chris-wilson.co.uk

Include all the number fields for describing the GT, as well as the
current boolean flags, primarily for inclusion in error states.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191207182937.2583002-1-chris@chris-wilson.co.uk

On converting from kunmap_atomic() to kunamp() one must remember the
latter takes the struct page, the former the vaddr.

Fixes: 48715f70 ("drm/i915: Avoid atomic context for error capture")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191125091409.1630385-1-chris@chris-wilson.co.uk

io_mapping_map_atomic/kmap_atomic are occasionally taken in error capture
(if there is no aperture preallocated for the use of error capture), but
the error capture and compression routines are now run in normal
context:

<3> [113.316247] BUG: sleeping function called from invalid context at mm/page_alloc.c:4653
<3> [113.318190] in_atomic(): 1, irqs_disabled(): 0, pid: 678, name: debugfs_test
<4> [113.319900] no locks held by debugfs_test/678.
<3> [113.321002] Preemption disabled at:
<4> [113.321130] [<ffffffffa02506d4>] i915_error_object_create+0x494/0x610 [i915]
<4> [113.327259] Call Trace:
<4> [113.327871] dump_stack+0x67/0x9b
<4> [113.328683] ___might_sleep+0x167/0x250
<4> [113.329618] __alloc_pages_nodemask+0x26b/0x1110
<4> [113.334614] pool_alloc.constprop.19+0x14/0x60 [i915]
<4> [113.335951] compress_page+0x7c/0x100 [i915]
<4> [113.337110] i915_error_object_create+0x4bd/0x610 [i915]
<4> [113.338515] i915_capture_gpu_state+0x384/0x1680 [i915]

However, it is not a good idea to run the slow compression inside atomic
context, so we choose not to.

Fixes: 895d8ebe ("drm/i915: error capture with no ggtt slot")
Signed-off-by: NBruce Chang <yu.bruce.chang@intel.com>
Reviewed-by: NBrian Welty <brian.welty@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191113231104.24208-1-yu.bruce.chang@intel.com
(cherry picked from commit 48715f70)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

io_mapping_map_atomic/kmap_atomic are occasionally taken in error capture
(if there is no aperture preallocated for the use of error capture), but
the error capture and compression routines are now run in normal
context:

<3> [113.316247] BUG: sleeping function called from invalid context at mm/page_alloc.c:4653
<3> [113.318190] in_atomic(): 1, irqs_disabled(): 0, pid: 678, name: debugfs_test
<4> [113.319900] no locks held by debugfs_test/678.
<3> [113.321002] Preemption disabled at:
<4> [113.321130] [<ffffffffa02506d4>] i915_error_object_create+0x494/0x610 [i915]
<4> [113.327259] Call Trace:
<4> [113.327871] dump_stack+0x67/0x9b
<4> [113.328683] ___might_sleep+0x167/0x250
<4> [113.329618] __alloc_pages_nodemask+0x26b/0x1110
<4> [113.334614] pool_alloc.constprop.19+0x14/0x60 [i915]
<4> [113.335951] compress_page+0x7c/0x100 [i915]
<4> [113.337110] i915_error_object_create+0x4bd/0x610 [i915]
<4> [113.338515] i915_capture_gpu_state+0x384/0x1680 [i915]

However, it is not a good idea to run the slow compression inside atomic
context, so we choose not to.

Fixes: 895d8ebe ("drm/i915: error capture with no ggtt slot")
Signed-off-by: NBruce Chang <yu.bruce.chang@intel.com>
Reviewed-by: NBrian Welty <brian.welty@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191113231104.24208-1-yu.bruce.chang@intel.com

We don't need rcu read side critical section to call pid_nr(),
remove it.
Signed-off-by: NNiranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191106172416.17188-1-chris@chris-wilson.co.uk

This has been asked from us already. Prepare for the next
time.
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029163841.5224-2-mika.kuoppala@linux.intel.com