6cd34b10cd
After a preempt-to-busy, we may find an active request that is caught between execution states. Walk back along the timeline instead of the execution list to be safe. [ 106.417541] i915 0000:00:02.0: Resetting rcs0 for preemption time out [ 106.417659] ================================================================== [ 106.418041] BUG: KASAN: slab-out-of-bounds in __execlists_reset+0x2f2/0x440 [i915] [ 106.418123] Read of size 8 at addr ffff888703506b30 by task swapper/1/0 [ 106.418194] [ 106.418267] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G U 5.3.0-rc3+ #5 [ 106.418344] Hardware name: Intel Corporation NUC7i5BNK/NUC7i5BNB, BIOS BNKBL357.86A.0052.2017.0918.1346 09/18/2017 [ 106.418434] Call Trace: [ 106.418508] <IRQ> [ 106.418585] dump_stack+0x5b/0x90 [ 106.418941] ? __execlists_reset+0x2f2/0x440 [i915] [ 106.419022] print_address_description+0x67/0x32d [ 106.419376] ? __execlists_reset+0x2f2/0x440 [i915] [ 106.419731] ? __execlists_reset+0x2f2/0x440 [i915] [ 106.419810] __kasan_report.cold.6+0x1a/0x3c [ 106.419888] ? __trace_bprintk+0xc0/0xd0 [ 106.420239] ? __execlists_reset+0x2f2/0x440 [i915] [ 106.420318] check_memory_region+0x144/0x1c0 [ 106.420671] __execlists_reset+0x2f2/0x440 [i915] [ 106.421029] execlists_reset+0x3d/0x50 [i915] [ 106.421387] intel_engine_reset+0x203/0x3a0 [i915] [ 106.421744] ? igt_reset_nop+0x2b0/0x2b0 [i915] [ 106.421825] ? _raw_spin_trylock_bh+0xe0/0xe0 [ 106.421901] ? rcu_core+0x1b9/0x6a0 [ 106.422251] preempt_reset+0x9a/0xf0 [i915] [ 106.422333] tasklet_action_common.isra.15+0xc0/0x1e0 [ 106.422685] ? execlists_submit_request+0x200/0x200 [i915] [ 106.422764] __do_softirq+0x106/0x3cf [ 106.422840] irq_exit+0xdc/0xf0 [ 106.422914] smp_apic_timer_interrupt+0x81/0x1c0 [ 106.422988] apic_timer_interrupt+0xf/0x20 [ 106.423059] </IRQ> [ 106.423144] RIP: 0010:cpuidle_enter_state+0xc3/0x620 [ 106.423222] Code: 24 0f 1f 44 00 00 31 ff e8 da 87 9c ff 80 7c 24 10 00 74 12 9c 58 f6 c4 02 0f 85 33 05 00 00 31 ff e8 c1 77 a3 ff fb 45 85 e4 <0f> 89 bf 02 00 00 48 8d 7d 10 e8 4e 45 b9 ff c7 45 10 00 00 00 00 [ 106.423311] RSP: 0018:ffff88881c30fda8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 [ 106.423390] RAX: 0000000000000000 RBX: ffffffff825b4c80 RCX: ffffffff810c8a00 [ 106.423465] RDX: dffffc0000000000 RSI: 0000000039f89620 RDI: ffff88881f6b00a8 [ 106.423540] RBP: ffff88881f6b5bf8 R08: 0000000000000002 R09: 000000000002ed80 [ 106.423616] R10: 0000003fdd956146 R11: ffff88881c2d1e47 R12: 0000000000000008 [ 106.423691] R13: 0000000000000008 R14: ffffffff825b4f80 R15: ffffffff825b4fc0 [ 106.423772] ? sched_idle_set_state+0x20/0x30 [ 106.423851] ? cpuidle_enter_state+0xa6/0x620 [ 106.423874] ? tick_nohz_idle_stop_tick+0x1d1/0x3f0 [ 106.423896] cpuidle_enter+0x37/0x60 [ 106.423919] do_idle+0x246/0x280 [ 106.423941] ? arch_cpu_idle_exit+0x30/0x30 [ 106.423964] ? __wake_up_common+0x46/0x240 [ 106.423986] cpu_startup_entry+0x14/0x20 [ 106.424009] start_secondary+0x1b0/0x200 [ 106.424031] ? set_cpu_sibling_map+0x990/0x990 [ 106.424054] secondary_startup_64+0xa4/0xb0 [ 106.424075] [ 106.424096] Allocated by task 626: [ 106.424119] save_stack+0x19/0x80 [ 106.424143] __kasan_kmalloc.constprop.7+0xc1/0xd0 [ 106.424165] kmem_cache_alloc+0xb2/0x1d0 [ 106.424277] i915_sched_lookup_priolist+0x1ab/0x320 [i915] [ 106.424385] execlists_submit_request+0x73/0x200 [i915] [ 106.424498] submit_notify+0x59/0x60 [i915] [ 106.424600] __i915_sw_fence_complete+0x9b/0x330 [i915] [ 106.424713] __i915_request_commit+0x4bf/0x570 [i915] [ 106.424818] intel_engine_pulse+0x213/0x310 [i915] [ 106.424925] context_close+0x22f/0x470 [i915] [ 106.425033] i915_gem_context_destroy_ioctl+0x7b/0xa0 [i915] [ 106.425058] drm_ioctl_kernel+0x131/0x170 [ 106.425081] drm_ioctl+0x2d9/0x4f1 [ 106.425104] do_vfs_ioctl+0x115/0x890 [ 106.425126] ksys_ioctl+0x35/0x70 [ 106.425147] __x64_sys_ioctl+0x38/0x40 [ 106.425169] do_syscall_64+0x66/0x220 [ 106.425191] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 106.425213] [ 106.425234] Freed by task 0: [ 106.425255] (stack is not available) [ 106.425276] [ 106.425297] The buggy address belongs to the object at ffff888703506a40 [ 106.425297] which belongs to the cache i915_priolist of size 104 [ 106.425321] The buggy address is located 136 bytes to the right of [ 106.425321] 104-byte region [ffff888703506a40, ffff888703506aa8) [ 106.425345] The buggy address belongs to the page: [ 106.425367] page:ffffea001c0d4180 refcount:1 mapcount:0 mapping:ffff88873e1cf740 index:0xffff888703506e40 compound_mapcount: 0 [ 106.425391] flags: 0x8000000000010200(slab|head) [ 106.425415] raw: 8000000000010200 ffffea0020192b88 ffff8888174b5450 ffff88873e1cf740 [ 106.425439] raw: ffff888703506e40 000000000010000e 00000001ffffffff 0000000000000000 [ 106.425464] page dumped because: kasan: bad access detected [ 106.425486] [ 106.425506] Memory state around the buggy address: [ 106.425528] ffff888703506a00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 [ 106.425551] ffff888703506a80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc [ 106.425573] >ffff888703506b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 106.425597] ^ [ 106.425619] ffff888703506b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 106.425642] ffff888703506c00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 [ 106.425664] ================================================================== Fixes: 22b7a426bbe1 ("drm/i915/execlists: Preempt-to-busy") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190809073723.6593-1-chris@chris-wilson.co.uk
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.