================================================================== BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x7d5/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1905 Read of size 1 at addr ffff8880202e0009 by task kworker/u33:9/1161 CPU: 1 UID: 0 PID: 1161 Comm: kworker/u33:9 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: events_unbound commit_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 drm_atomic_helper_wait_for_vblanks.part.0+0x7d5/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1905 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1901 [inline] drm_atomic_helper_commit_tail+0xff/0x130 drivers/gpu/drm/drm_atomic_helper.c:2003 commit_tail+0x338/0x430 drivers/gpu/drm/drm_atomic_helper.c:2080 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 13761: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x2f8/0x6d0 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] drm_atomic_helper_crtc_duplicate_state+0x72/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:204 drm_atomic_get_crtc_state+0x1de/0x690 drivers/gpu/drm/drm_atomic.c:462 drm_atomic_set_property+0x165/0x3f90 drivers/gpu/drm/drm_atomic_uapi.c:1244 drm_mode_atomic_ioctl+0x6ed/0x2940 drivers/gpu/drm/drm_atomic_uapi.c:1744 drm_ioctl_kernel+0x1f3/0x3e0 drivers/gpu/drm/drm_ioctl.c:817 drm_ioctl+0x5e6/0xc60 drivers/gpu/drm/drm_ioctl.c:914 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 2564: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6508 [inline] kfree+0x22b/0x6d0 mm/slub.c:6801 drm_atomic_commit_default_clear+0x465/0x10c0 drivers/gpu/drm/drm_atomic.c:311 drm_atomic_commit_clear drivers/gpu/drm/drm_atomic.c:394 [inline] __drm_atomic_commit_free+0x185/0x2f0 drivers/gpu/drm/drm_atomic.c:411 kref_put include/linux/kref.h:65 [inline] drm_atomic_commit_put include/drm/drm_atomic.h:713 [inline] drm_atomic_helper_dirtyfb+0x578/0x790 drivers/gpu/drm/drm_damage_helper.c:195 drm_fbdev_shmem_helper_fb_dirty+0x1cc/0x350 drivers/gpu/drm/drm_fbdev_shmem.c:117 drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:339 [inline] drm_fb_helper_damage_work+0x4c8/0xab0 drivers/gpu/drm/drm_fb_helper.c:365 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3396 process_scheduled_works kernel/workqueue.c:3479 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3560 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff8880202e0000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 9 bytes inside of freed 512-byte region [ffff8880202e0000, ffff8880202e0200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x202e0 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801c042c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801c042c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 2287938432 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x110d/0x35d0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab mm/slub.c:3462 [inline] new_slab+0xa9/0x6e0 mm/slub.c:3513 refill_objects+0xe3/0x410 mm/slub.c:7417 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_flags_noprof+0x6a9/0x8e0 mm/slub.c:5602 _kmalloc_flags_noprof mm/slab.h:55 [inline] __alloc_empty_sheaf mm/slub.c:2822 [inline] alloc_empty_sheaf mm/slub.c:2842 [inline] init_percpu_sheaves mm/slub.c:7740 [inline] do_kmem_cache_create+0x6fc/0x7a0 mm/slub.c:8790 create_cache mm/slab_common.c:252 [inline] __kmem_cache_create_args+0x1e3/0x430 mm/slab_common.c:387 audit_init+0x74/0x220 kernel/audit.c:1743 do_one_initcall+0x11c/0x6f0 init/main.c:1362 do_initcall_level init/main.c:1424 [inline] do_initcalls init/main.c:1440 [inline] do_basic_setup init/main.c:1460 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1675 kernel_init+0x21/0x1e0 init/main.c:1565 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page_owner free stack trace missing Memory state around the buggy address: ffff8880202dff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880202dff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880202e0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880202e0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880202e0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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