From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> commit 20612303a0b45de748d31331407e84300c38e497 upstream. (NOTE: This is the minimal backportable fix, a full fix is being developed at https://patchwork.freedesktop.org/patch/388048/) The flags passed to the wait_entry.func are passed onwards to try_to_wake_up(), which has a very particular interpretation for its wake_flags. In particular, beyond the published WF_SYNC, it has a few internal flags as well. Since we passed the fence->error down the chain via the flags argument, these ended up in the default_wake_function confusing the kernel/sched. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2110 Fixes: ef4688497512 ("drm/i915: Propagate fence errors") Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Matthew Auld <matthew.auld@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v5.4+ Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20200728152144.1100-1-chris@xxxxxxxxxxxxxxxxxx Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> [Joonas: Rebased and reordered into drm-intel-gt-next branch] [Joonas: Added a note and link about more complete fix] Signed-off-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> (cherry picked from commit f4b3c395540aa3d4f5a6275c5bdd83ab89034806) Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/i915_sw_fence.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/i915/i915_sw_fence.c +++ b/drivers/gpu/drm/i915/i915_sw_fence.c @@ -164,9 +164,13 @@ static void __i915_sw_fence_wake_up_all( do { list_for_each_entry_safe(pos, next, &x->head, entry) { - pos->func(pos, - TASK_NORMAL, fence->error, - &extra); + int wake_flags; + + wake_flags = fence->error; + if (pos->func == autoremove_wake_function) + wake_flags = 0; + + pos->func(pos, TASK_NORMAL, wake_flags, &extra); } if (list_empty(&extra))
