Commit e2b763caa6 ("drm/i915: Remove bitmap tracking for used-pdpes") believed that because it did not insert its freshly allocated page directory into the pd tree, it was safe from the shrinker. I failed to heed the lesson learnt from commit dd19674bac ("drm/i915: Remove bitmap tracking for used-ptes") that we need to pin all the levels in the tree before hitting the shrinker or else the shrinker may free an upper layer as we proceed to allocate the tree. Thus leaving dangling pointers everywhere and a GPF should we hit direct reclaim at just the wrong moment. CPU: 0 PID: 7374 Comm: chromium Tainted: P O 4.14.13-1-ARCH #1 Hardware name: Apple Inc. MacBookPro12,1/Mac-E43C1C25D4880AD6, BIOS MBP121.88Z.0167.B33.1706181928 06/18/2017 task: ffff994f696c2c40 task.stack: ffffb1a789d4c000 RIP: 0010:gen8_ppgtt_set_pde.isra.40+0x48/0x70 [i915] RSP: 0018:ffffb1a789d4f940 EFLAGS: 00010206 RAX: 81c1788cc4f68138 RBX: ffff994f54db8000 RCX: ffff994f696c2c40 RDX: 000000023bc73003 RSI: ffff994d598b6b80 RDI: ffff994f54db8000 RBP: ffff994d598b6b80 R08: 0000000000000000 R09: 0000000000000000 R10: ffffb1a789d4f550 R11: ffff994eaf3c3208 R12: 0000000000000027 R13: 0000000000005000 R14: 0000000004e8f000 R15: ffff994f54dba000 FS: 00007f585886aa00(0000) GS:ffff994faec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004ac8e8 CR3: 00000002552c8004 CR4: 00000000003606f0 Call Trace: gen8_ppgtt_alloc_pdp+0x178/0x320 [i915] gen8_ppgtt_alloc_4lvl+0x5f/0x150 [i915] ppgtt_bind_vma+0x30/0x70 [i915] i915_vma_bind+0x68/0xd0 [i915] __i915_vma_do_pin+0x2d6/0x3a0 [i915] eb_lookup_vmas+0x7a2/0xb50 [i915] i915_gem_do_execbuffer+0x4d7/0x10e0 [i915] ? sock_wfree+0x34/0x60 ? unix_stream_read_generic+0x1f9/0x7e0 ? import_iovec+0x37/0xd0 ? i915_gem_execbuffer2+0x5d/0x390 [i915] i915_gem_execbuffer2+0x1b7/0x390 [i915] ? i915_gem_execbuffer+0x2d0/0x2d0 [i915] drm_ioctl_kernel+0x59/0xb0 [drm] drm_ioctl+0x2d5/0x370 [drm] ? i915_gem_execbuffer+0x2d0/0x2d0 [i915] ? __seccomp_filter+0x3b/0x260 do_vfs_ioctl+0xa1/0x610 ? syscall_trace_enter+0xdb/0x2b0 SyS_ioctl+0x74/0x80 do_syscall_64+0x55/0x110 entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7f584fa82d27 RSP: 002b:00007ffee14a7828 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000003b0126a1030 RCX: 00007f584fa82d27 RDX: 00007ffee14a7870 RSI: 0000000040406469 RDI: 0000000000000080 RBP: 00007ffee14a7870 R08: 0000000000000002 R09: 0000000000000077 R10: 00007f5839f2b780 R11: 0000000000000246 R12: 0000000040406469 R13: 0000000000000080 R14: 00007f5842b00040 R15: 0000000000000000 Code: 01 00 83 81 58 0a 00 00 01 48 2b 05 13 9d fd c9 48 c1 f8 06 48 c1 e0 0c 48 8d 04 d0 48 8b 56 08 48 03 05 0c 9d fd c9 48 83 ca 03 <48> 89 10 83 a9 58 0a 00 00 01 65 ff 0d 37 03 fb 3e 74 02 f3 c3 RIP: gen8_ppgtt_set_pde.isra.40+0x48/0x70 [i915] RSP: ffffb1a789d4f940 Reported-by: Eric Blau <eblau@eblau.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104773 Fixes: e2b763caa6 ("drm/i915: Remove bitmap tracking for used-pdpes") References: dd19674bac ("drm/i915: Remove bitmap tracking for used-ptes") Testcase: igt/drv_selftest/live_gtt (igt_ppgtt_shrink_boom) Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180131214440.7141-1-chris@chris-wilson.co.uk Reviewed-by: Matthew Auld <matthew.auld@intel.com> (cherry picked from commit b715a2f0c7) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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