linux/drivers/gpu/drm
Chris Wilson 03d1cac6ee drm/i915: Avoiding recursing on ww_mutex inside shrinker
We have to avoid taking ww_mutex inside the shrinker as we use it as a
plain mutex type and so need to avoid recursive deadlocks:

[  602.771969] =================================
[  602.771970] [ INFO: inconsistent lock state ]
[  602.771973] 4.10.0gpudebug+ #122 Not tainted
[  602.771974] ---------------------------------
[  602.771975] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
[  602.771978] kswapd0/40 [HC0[0]:SC0[0]:HE1:SE1] takes:
[  602.771979]  (reservation_ww_class_mutex){+.+.?.}, at: [<ffffffffa054680a>] i915_gem_object_wait+0x39a/0x410 [i915]
[  602.772020] {RECLAIM_FS-ON-W} state was registered at:
[  602.772024]   mark_held_locks+0x76/0x90
[  602.772026]   lockdep_trace_alloc+0xb8/0xc0
[  602.772028]   __kmalloc_track_caller+0x5d/0x130
[  602.772031]   krealloc+0x89/0xb0
[  602.772033]   reservation_object_reserve_shared+0xaf/0xd0
[  602.772055]   i915_gem_do_execbuffer.isra.35+0x1413/0x18b0 [i915]
[  602.772075]   i915_gem_execbuffer2+0x10e/0x1d0 [i915]
[  602.772078]   drm_ioctl+0x291/0x480
[  602.772079]   do_vfs_ioctl+0x695/0x6f0
[  602.772081]   SyS_ioctl+0x3c/0x70
[  602.772084]   entry_SYSCALL_64_fastpath+0x18/0xad
[  602.772085] irq event stamp: 5197423
[  602.772088] hardirqs last  enabled at (5197423): [<ffffffff8116751d>] kfree+0xdd/0x170
[  602.772091] hardirqs last disabled at (5197422): [<ffffffff811674f9>] kfree+0xb9/0x170
[  602.772095] softirqs last  enabled at (5190992): [<ffffffff8107bfe1>] __do_softirq+0x221/0x280
[  602.772097] softirqs last disabled at (5190575): [<ffffffff8107c294>] irq_exit+0x64/0xc0
[  602.772099]
               other info that might help us debug this:
[  602.772100]  Possible unsafe locking scenario:

[  602.772101]        CPU0
[  602.772101]        ----
[  602.772102]   lock(reservation_ww_class_mutex);
[  602.772104]   <Interrupt>
[  602.772105]     lock(reservation_ww_class_mutex);
[  602.772107]
                *** DEADLOCK ***

[  602.772109] 2 locks held by kswapd0/40:
[  602.772110]  #0:  (shrinker_rwsem){++++..}, at: [<ffffffff811337b5>] shrink_slab.constprop.62+0x35/0x280
[  602.772116]  #1:  (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa0553957>] i915_gem_shrinker_lock+0x27/0x60 [i915]
[  602.772141]
               stack backtrace:
[  602.772144] CPU: 2 PID: 40 Comm: kswapd0 Not tainted 4.10.0gpudebug+ #122
[  602.772145] Hardware name: LENOVO 42433ZG/42433ZG, BIOS 8AET64WW (1.44 ) 07/26/2013
[  602.772147] Call Trace:
[  602.772151]  dump_stack+0x68/0xa1
[  602.772153]  print_usage_bug+0x1d4/0x1f0
[  602.772155]  mark_lock+0x390/0x530
[  602.772157]  ? print_irq_inversion_bug+0x200/0x200
[  602.772159]  __lock_acquire+0x405/0x1260
[  602.772181]  ? i915_gem_object_wait+0x39a/0x410 [i915]
[  602.772183]  lock_acquire+0x60/0x80
[  602.772205]  ? i915_gem_object_wait+0x39a/0x410 [i915]
[  602.772207]  mutex_lock_nested+0x69/0x760
[  602.772229]  ? i915_gem_object_wait+0x39a/0x410 [i915]
[  602.772231]  ? kfree+0xdd/0x170
[  602.772253]  ? i915_gem_object_wait+0x163/0x410 [i915]
[  602.772255]  ? trace_hardirqs_on_caller+0x18d/0x1c0
[  602.772256]  ? trace_hardirqs_on+0xd/0x10
[  602.772278]  i915_gem_object_wait+0x39a/0x410 [i915]
[  602.772300]  i915_gem_object_unbind+0x5e/0x130 [i915]
[  602.772323]  i915_gem_shrink+0x22d/0x3d0 [i915]
[  602.772347]  i915_gem_shrinker_scan+0x3f/0x80 [i915]
[  602.772349]  shrink_slab.constprop.62+0x1ad/0x280
[  602.772352]  shrink_node+0x52/0x80
[  602.772355]  kswapd+0x427/0x5c0
[  602.772358]  kthread+0x122/0x130
[  602.772360]  ? try_to_free_pages+0x270/0x270
[  602.772362]  ? kthread_stop+0x70/0x70
[  602.772365]  ret_from_fork+0x2e/0x40

v2: Add commentary about the pruning being opportunistic

Reported-by: Jan Nordholz <jckn@gmx.net>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99977#c10
Fixes: e54ca97747 ("drm/i915: Remove completed fences after a wait")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170308132629.7987-1-chris@chris-wilson.co.uk
2017-03-08 20:42:17 +00:00
..
amd Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
arc
arm
armada Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
ast Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
atmel-hlcdc
bochs
bridge
cirrus
etnaviv
exynos Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
fsl-dcu
gma500 Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
hisilicon
i2c
i810
i915 drm/i915: Avoiding recursing on ww_mutex inside shrinker 2017-03-08 20:42:17 +00:00
imx
lib
mediatek
meson
mga
mgag200
msm Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
mxsfb
nouveau Merge branch 'linux-4.12' of git://github.com/skeggsb/linux into drm-next 2017-03-08 12:54:58 +10:00
omapdrm Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
panel
qxl Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
r128
radeon Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
rcar-du
rockchip Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
savage
selftests
shmobile
sis
sti
sun4i
tdfx
tegra Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
tilcdc
tinydrm Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
ttm Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
udl Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
vc4 Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
vgem Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-03-02 15:20:00 -08:00
via
virtio Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
vmwgfx Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
zte Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
ati_pcigart.c
drm_agpsupport.c
drm_atomic.c
drm_atomic_helper.c
drm_auth.c
drm_blend.c
drm_bridge.c
drm_bufs.c
drm_cache.c
drm_color_mgmt.c
drm_connector.c
drm_context.c
drm_crtc.c
drm_crtc_helper.c
drm_crtc_helper_internal.h
drm_crtc_internal.h
drm_debugfs.c
drm_debugfs_crc.c
drm_dma.c
drm_dp_aux_dev.c
drm_dp_dual_mode_helper.c
drm_dp_helper.c
drm_dp_mst_topology.c
drm_drv.c
drm_dumb_buffers.c
drm_edid.c
drm_edid_load.c
drm_encoder.c
drm_encoder_slave.c
drm_fb_cma_helper.c
drm_fb_helper.c
drm_flip_work.c
drm_fops.c
drm_fourcc.c
drm_framebuffer.c
drm_gem.c
drm_gem_cma_helper.c Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
drm_global.c
drm_hashtab.c
drm_info.c
drm_internal.h
drm_ioc32.c
drm_ioctl.c
drm_irq.c
drm_kms_helper_common.c
drm_legacy.h
drm_lock.c
drm_memory.c
drm_mipi_dsi.c
drm_mm.c
drm_mode_config.c
drm_mode_object.c Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
drm_modes.c
drm_modeset_helper.c
drm_modeset_lock.c
drm_of.c
drm_panel.c
drm_pci.c
drm_plane.c
drm_plane_helper.c
drm_platform.c
drm_prime.c
drm_print.c
drm_probe_helper.c Merge tag 'drm-misc-next-2017-03-06' of git://anongit.freedesktop.org/git/drm-misc into drm-next 2017-03-07 13:59:53 +10:00
drm_property.c
drm_rect.c
drm_scatter.c
drm_simple_kms_helper.c
drm_sysfs.c
drm_trace.h
drm_trace_points.c
drm_vm.c
drm_vma_manager.c
Kconfig
Makefile