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70deeaddc6
This patch fixes lockdep issue due to circular locking dependency of struct_mutex, i_mutex_key, mmap_sem, relay_channels_mutex. For GuC log relay channel we create debugfs file that requires i_mutex_key lock and we are doing that under struct_mutex. So we introduced newer dependency as: &dev->struct_mutex --> &sb->s_type->i_mutex_key#3 --> &mm->mmap_sem However, there is dependency from mmap_sem to struct_mutex. Hence we separate the relay create/destroy operation from under struct_mutex. Also added runtime check of relay buffer status. Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> ====================================================== WARNING: possible circular locking dependency detected 4.15.0-rc6-CI-Patchwork_7614+ #1 Not tainted ------------------------------------------------------ debugfs_test/1388 is trying to acquire lock: (&dev->struct_mutex){+.+.}, at: [<00000000d5e1d915>] i915_mutex_lock_interruptible+0x47/0x130 [i915] but task is already holding lock: (&mm->mmap_sem){++++}, at: [<0000000029a9c131>] __do_page_fault+0x106/0x560 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&mm->mmap_sem){++++}: _copy_to_user+0x1e/0x70 filldir+0x8c/0xf0 dcache_readdir+0xeb/0x160 iterate_dir+0xdc/0x140 SyS_getdents+0xa0/0x130 entry_SYSCALL_64_fastpath+0x1c/0x89 -> #2 (&sb->s_type->i_mutex_key#3){++++}: start_creating+0x59/0x110 __debugfs_create_file+0x2e/0xe0 relay_create_buf_file+0x62/0x80 relay_late_setup_files+0x84/0x250 guc_log_late_setup+0x4f/0x110 [i915] i915_guc_log_register+0x32/0x40 [i915] i915_driver_load+0x7b6/0x1720 [i915] i915_pci_probe+0x2e/0x90 [i915] pci_device_probe+0x9c/0x120 driver_probe_device+0x2a3/0x480 __driver_attach+0xd9/0xe0 bus_for_each_dev+0x57/0x90 bus_add_driver+0x168/0x260 driver_register+0x52/0xc0 do_one_initcall+0x39/0x150 do_init_module+0x56/0x1ef load_module+0x231c/0x2d70 SyS_finit_module+0xa5/0xe0 entry_SYSCALL_64_fastpath+0x1c/0x89 -> #1 (relay_channels_mutex){+.+.}: relay_open+0x12c/0x2b0 intel_guc_log_runtime_create+0xab/0x230 [i915] intel_guc_init+0x81/0x120 [i915] intel_uc_init+0x29/0xa0 [i915] i915_gem_init+0x182/0x530 [i915] i915_driver_load+0xaa9/0x1720 [i915] i915_pci_probe+0x2e/0x90 [i915] pci_device_probe+0x9c/0x120 driver_probe_device+0x2a3/0x480 __driver_attach+0xd9/0xe0 bus_for_each_dev+0x57/0x90 bus_add_driver+0x168/0x260 driver_register+0x52/0xc0 do_one_initcall+0x39/0x150 do_init_module+0x56/0x1ef load_module+0x231c/0x2d70 SyS_finit_module+0xa5/0xe0 entry_SYSCALL_64_fastpath+0x1c/0x89 -> #0 (&dev->struct_mutex){+.+.}: __mutex_lock+0x81/0x9b0 i915_mutex_lock_interruptible+0x47/0x130 [i915] i915_gem_fault+0x201/0x790 [i915] __do_fault+0x15/0x70 __handle_mm_fault+0x677/0xdc0 handle_mm_fault+0x14f/0x2f0 __do_page_fault+0x2d1/0x560 page_fault+0x4c/0x60 other info that might help us debug this: Chain exists of: &dev->struct_mutex --> &sb->s_type->i_mutex_key#3 --> &mm->mmap_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(&sb->s_type->i_mutex_key#3); lock(&mm->mmap_sem); lock(&dev->struct_mutex); *** DEADLOCK *** 1 lock held by debugfs_test/1388: #0: (&mm->mmap_sem){++++}, at: [<0000000029a9c131>] __do_page_fault+0x106/0x560 stack backtrace: CPU: 2 PID: 1388 Comm: debugfs_test Not tainted 4.15.0-rc6-CI-Patchwork_7614+ #1 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./J4205-ITX, BIOS P1.10 09/29/2016 Call Trace: dump_stack+0x5f/0x86 print_circular_bug.isra.18+0x1d0/0x2c0 __lock_acquire+0x14ae/0x1b60 ? lock_acquire+0xaf/0x200 lock_acquire+0xaf/0x200 ? i915_mutex_lock_interruptible+0x47/0x130 [i915] __mutex_lock+0x81/0x9b0 ? i915_mutex_lock_interruptible+0x47/0x130 [i915] ? i915_mutex_lock_interruptible+0x47/0x130 [i915] ? i915_mutex_lock_interruptible+0x47/0x130 [i915] i915_mutex_lock_interruptible+0x47/0x130 [i915] ? __pm_runtime_resume+0x4f/0x80 i915_gem_fault+0x201/0x790 [i915] __do_fault+0x15/0x70 ? _raw_spin_unlock+0x29/0x40 __handle_mm_fault+0x677/0xdc0 handle_mm_fault+0x14f/0x2f0 __do_page_fault+0x2d1/0x560 ? page_fault+0x36/0x60 page_fault+0x4c/0x60 v2: Added lock protection to guc->log.runtime.relay_chan (Chris) Fixed locking inside guc_flush_logs uncovered by new lockdep. v3: Locking guc_read_update_log_buffer entirely with relay_lock. (Chris) Prepared intel_guc_init_early. Moved relay_lock inside relay_create relay_destroy, relay_file_create, guc_read_update_log_buffer. (Michal) Removed struct_mutex lock around guc_log_flush and removed usage of guc_log_has_relay() from runtime_create path as it needs struct_mutex lock. v4: Handle NULL relay sub buffer pointer earlier in read_update_log_buffer (Chris). Fixed comment suffix **/. (Michal) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104693 Testcase: igt/debugfs_test/read_all_entries # with enable_guc=1 and guc_log_level=1 Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Marta Lofstedt <marta.lofstedt@intel.com> Cc: Michal Winiarski <michal.winiarski@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/1516808821-3638-3-git-send-email-sagar.a.kamble@intel.com |
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amd | ||
arc | ||
arm | ||
armada | ||
ast | ||
atmel-hlcdc | ||
bochs | ||
bridge | ||
cirrus | ||
etnaviv | ||
exynos | ||
fsl-dcu | ||
gma500 | ||
hisilicon | ||
i2c | ||
i810 | ||
i915 | ||
imx | ||
lib | ||
mediatek | ||
meson | ||
mga | ||
mgag200 | ||
msm | ||
mxsfb | ||
nouveau | ||
omapdrm | ||
panel | ||
pl111 | ||
qxl | ||
r128 | ||
radeon | ||
rcar-du | ||
rockchip | ||
savage | ||
selftests | ||
shmobile | ||
sis | ||
sti | ||
stm | ||
sun4i | ||
tdfx | ||
tegra | ||
tilcdc | ||
tinydrm | ||
ttm | ||
tve200 | ||
udl | ||
vc4 | ||
vgem | ||
via | ||
virtio | ||
vmwgfx | ||
zte | ||
ati_pcigart.c | ||
drm_agpsupport.c | ||
drm_atomic_helper.c | ||
drm_atomic.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_helper_internal.h | ||
drm_crtc_helper.c | ||
drm_crtc_internal.h | ||
drm_crtc.c | ||
drm_debugfs_crc.c | ||
drm_debugfs.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_load.c | ||
drm_edid.c | ||
drm_encoder_slave.c | ||
drm_encoder.c | ||
drm_fb_cma_helper.c | ||
drm_fb_helper.c | ||
drm_file.c | ||
drm_flip_work.c | ||
drm_fourcc.c | ||
drm_framebuffer.c | ||
drm_gem_cma_helper.c | ||
drm_gem_framebuffer_helper.c | ||
drm_gem.c | ||
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_lease.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 | ||
drm_modes.c | ||
drm_modeset_helper.c | ||
drm_modeset_lock.c | ||
drm_of.c | ||
drm_panel_orientation_quirks.c | ||
drm_panel.c | ||
drm_pci.c | ||
drm_plane_helper.c | ||
drm_plane.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_simple_kms_helper.c | ||
drm_syncobj.c | ||
drm_sysfs.c | ||
drm_trace_points.c | ||
drm_trace.h | ||
drm_vblank.c | ||
drm_vm.c | ||
drm_vma_manager.c | ||
Kconfig | ||
Makefile |