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dfbc7a46b9
Lockdep reports a circular locking dependency with pages_lock taken in
the shrinker callback. The deadlock can't actually happen with current
users at least as a BO will never be purgeable when pages_lock is held.
To be safe, let's use mutex_trylock() instead and bail if a BO is locked
already.
WARNING: possible circular locking dependency detected
5.3.0-rc1+ #100 Tainted: G L
------------------------------------------------------
kswapd0/171 is trying to acquire lock:
000000009b9823fd (&shmem->pages_lock){+.+.}, at: drm_gem_shmem_purge+0x20/0x40
but task is already holding lock:
00000000f82369b6 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x40
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}:
fs_reclaim_acquire.part.18+0x34/0x40
fs_reclaim_acquire+0x20/0x28
__kmalloc_node+0x6c/0x4c0
kvmalloc_node+0x38/0xa8
drm_gem_get_pages+0x80/0x1d0
drm_gem_shmem_get_pages+0x58/0xa0
drm_gem_shmem_get_pages_sgt+0x48/0xd0
panfrost_mmu_map+0x38/0xf8 [panfrost]
panfrost_gem_open+0xc0/0xe8 [panfrost]
drm_gem_handle_create_tail+0xe8/0x198
drm_gem_handle_create+0x3c/0x50
panfrost_gem_create_with_handle+0x70/0xa0 [panfrost]
panfrost_ioctl_create_bo+0x48/0x80 [panfrost]
drm_ioctl_kernel+0xb8/0x110
drm_ioctl+0x244/0x3f0
do_vfs_ioctl+0xbc/0x910
ksys_ioctl+0x78/0xa8
__arm64_sys_ioctl+0x1c/0x28
el0_svc_common.constprop.0+0x90/0x168
el0_svc_handler+0x28/0x78
el0_svc+0x8/0xc
-> #0 (&shmem->pages_lock){+.+.}:
__lock_acquire+0xa2c/0x1d70
lock_acquire+0xdc/0x228
__mutex_lock+0x8c/0x800
mutex_lock_nested+0x1c/0x28
drm_gem_shmem_purge+0x20/0x40
panfrost_gem_shrinker_scan+0xc0/0x180 [panfrost]
do_shrink_slab+0x208/0x500
shrink_slab+0x10c/0x2c0
shrink_node+0x28c/0x4d8
balance_pgdat+0x2c8/0x570
kswapd+0x22c/0x638
kthread+0x128/0x130
ret_from_fork+0x10/0x18
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&shmem->pages_lock);
lock(fs_reclaim);
lock(&shmem->pages_lock);
*** DEADLOCK ***
3 locks held by kswapd0/171:
#0: 00000000f82369b6 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x40
#1: 00000000ceb37808 (shrinker_rwsem){++++}, at: shrink_slab+0xbc/0x2c0
#2: 00000000f31efa81 (&pfdev->shrinker_lock){+.+.}, at: panfrost_gem_shrinker_scan+0x34/0x180 [panfrost]
Fixes:
|
||
|---|---|---|
| .. | ||
| amd | ||
| arc | ||
| arm | ||
| armada | ||
| aspeed | ||
| ast | ||
| atmel-hlcdc | ||
| bochs | ||
| bridge | ||
| cirrus | ||
| etnaviv | ||
| exynos | ||
| fsl-dcu | ||
| gma500 | ||
| hisilicon | ||
| i2c | ||
| i810 | ||
| i915 | ||
| imx | ||
| ingenic | ||
| lib | ||
| lima | ||
| mcde | ||
| mediatek | ||
| meson | ||
| mga | ||
| mgag200 | ||
| msm | ||
| mxsfb | ||
| nouveau | ||
| omapdrm | ||
| panel | ||
| panfrost | ||
| pl111 | ||
| qxl | ||
| r128 | ||
| radeon | ||
| rcar-du | ||
| rockchip | ||
| savage | ||
| scheduler | ||
| selftests | ||
| shmobile | ||
| sis | ||
| sti | ||
| stm | ||
| sun4i | ||
| tdfx | ||
| tegra | ||
| tilcdc | ||
| tiny | ||
| ttm | ||
| tve200 | ||
| udl | ||
| v3d | ||
| vboxvideo | ||
| vc4 | ||
| vgem | ||
| via | ||
| virtio | ||
| vkms | ||
| vmwgfx | ||
| xen | ||
| zte | ||
| ati_pcigart.c | ||
| drm_agpsupport.c | ||
| drm_atomic.c | ||
| drm_atomic_helper.c | ||
| drm_atomic_state_helper.c | ||
| drm_atomic_uapi.c | ||
| drm_auth.c | ||
| drm_blend.c | ||
| drm_bridge.c | ||
| drm_bufs.c | ||
| drm_cache.c | ||
| drm_client.c | ||
| drm_client_modeset.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_damage_helper.c | ||
| drm_debugfs.c | ||
| drm_debugfs_crc.c | ||
| drm_dma.c | ||
| drm_dp_aux_dev.c | ||
| drm_dp_cec.c | ||
| drm_dp_dual_mode_helper.c | ||
| drm_dp_helper.c | ||
| drm_dp_mst_topology.c | ||
| drm_drv.c | ||
| drm_dsc.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_file.c | ||
| drm_flip_work.c | ||
| drm_format_helper.c | ||
| drm_fourcc.c | ||
| drm_framebuffer.c | ||
| drm_gem.c | ||
| drm_gem_cma_helper.c | ||
| drm_gem_framebuffer_helper.c | ||
| drm_gem_shmem_helper.c | ||
| drm_gem_vram_helper.c | ||
| drm_hashtab.c | ||
| drm_hdcp.c | ||
| drm_internal.h | ||
| drm_ioc32.c | ||
| drm_ioctl.c | ||
| drm_irq.c | ||
| drm_kms_helper_common.c | ||
| drm_lease.c | ||
| drm_legacy.h | ||
| drm_legacy_misc.c | ||
| drm_lock.c | ||
| drm_memory.c | ||
| drm_mipi_dbi.c | ||
| drm_mipi_dsi.c | ||
| drm_mm.c | ||
| drm_mode_config.c | ||
| drm_mode_object.c | ||
| drm_modes.c | ||
| drm_modeset_helper.c | ||
| drm_modeset_lock.c | ||
| drm_of.c | ||
| drm_panel.c | ||
| drm_panel_orientation_quirks.c | ||
| drm_pci.c | ||
| drm_plane.c | ||
| drm_plane_helper.c | ||
| drm_prime.c | ||
| drm_print.c | ||
| drm_probe_helper.c | ||
| drm_property.c | ||
| drm_rect.c | ||
| drm_scatter.c | ||
| drm_scdc_helper.c | ||
| drm_self_refresh_helper.c | ||
| drm_simple_kms_helper.c | ||
| drm_syncobj.c | ||
| drm_sysfs.c | ||
| drm_trace.h | ||
| drm_trace_points.c | ||
| drm_vblank.c | ||
| drm_vm.c | ||
| drm_vma_manager.c | ||
| drm_vram_helper_common.c | ||
| drm_vram_mm_helper.c | ||
| drm_writeback.c | ||
| Kconfig | ||
| Makefile | ||