syzbot

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BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x8c0/0x9b0 drivers/gpu/drm/drm_atomic_helper.c:1822
Read of size 1 at addr ffff88802cc7ec09 by task kworker/u32:9/1178

CPU: 2 UID: 0 PID: 1178 Comm: kworker/u32:9 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events_unbound commit_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 drm_atomic_helper_wait_for_vblanks.part.0+0x8c0/0x9b0 drivers/gpu/drm/drm_atomic_helper.c:1822
 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1818 [inline]
 drm_atomic_helper_commit_tail+0xe1/0x110 drivers/gpu/drm/drm_atomic_helper.c:1918
 commit_tail+0x35b/0x400 drivers/gpu/drm/drm_atomic_helper.c:1995
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6476:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
 kmalloc_noprof include/linux/slab.h:957 [inline]
 drm_atomic_helper_crtc_duplicate_state+0x70/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:178
 drm_atomic_get_crtc_state+0x171/0x450 drivers/gpu/drm/drm_atomic.c:360
 page_flip_common+0x57/0x320 drivers/gpu/drm/drm_atomic_helper.c:3839
 drm_atomic_helper_page_flip+0xb6/0x180 drivers/gpu/drm/drm_atomic_helper.c:3900
 drm_mode_page_flip_ioctl+0x102c/0x1460 drivers/gpu/drm/drm_plane.c:1543
 drm_ioctl_kernel+0x1f4/0x3e0 drivers/gpu/drm/drm_ioctl.c:797
 drm_ioctl+0x5c9/0xc30 drivers/gpu/drm/drm_ioctl.c:894
 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:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6476:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2543 [inline]
 slab_free mm/slub.c:6642 [inline]
 kfree+0x2b8/0x6d0 mm/slub.c:6849
 drm_atomic_state_default_clear+0x458/0xe40 drivers/gpu/drm/drm_atomic.c:224
 drm_atomic_state_clear drivers/gpu/drm/drm_atomic.c:293 [inline]
 __drm_atomic_state_free+0x185/0x2b0 drivers/gpu/drm/drm_atomic.c:310
 kref_put include/linux/kref.h:65 [inline]
 drm_atomic_state_put include/drm/drm_atomic.h:588 [inline]
 drm_client_modeset_commit_atomic+0x6b2/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1109
 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1206
 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1232
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:236 [inline]
 __drm_fb_helper_restore_fbdev_mode_unlocked+0x19f/0x200 drivers/gpu/drm/drm_fb_helper.c:215
 drm_fbdev_client_restore+0x2c/0x40 drivers/gpu/drm/clients/drm_fbdev_client.c:31
 drm_client_dev_restore+0x1f6/0x2a0 drivers/gpu/drm/drm_client_event.c:117
 drm_lastclose drivers/gpu/drm/drm_file.c:408 [inline]
 drm_release+0x2c4/0x360 drivers/gpu/drm/drm_file.c:441
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xec/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802cc7ec00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 9 bytes inside of
 freed 512-byte region [ffff88802cc7ec00, ffff88802cc7ee00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2cc7c
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 ffff88801b442c80 ffffea0000a72c00 dead000000000002
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b442c80 ffffea0000a72c00 dead000000000002
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000b31f01 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 6047, tgid 6047 (syz-executor), ts 64456259101, free_ts 62662355428
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1845
 prep_new_page mm/page_alloc.c:1853 [inline]
 get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3879
 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5178
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:3059 [inline]
 allocate_slab mm/slub.c:3232 [inline]
 new_slab+0x24a/0x360 mm/slub.c:3286
 ___slab_alloc+0xd79/0x1a50 mm/slub.c:4655
 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4778
 __slab_alloc_node mm/slub.c:4854 [inline]
 slab_alloc_node mm/slub.c:5276 [inline]
 __do_kmalloc_node mm/slub.c:5649 [inline]
 __kmalloc_noprof+0x501/0x880 mm/slub.c:5662
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155
 ip6_route_info_create+0x14c/0x870 net/ipv6/route.c:3809
 ip6_route_add.part.0+0x22/0x1d0 net/ipv6/route.c:3938
 ip6_route_add+0x45/0x60 net/ipv6/route.c:3935
 addrconf_prefix_route+0x2fd/0x510 net/ipv6/addrconf.c:2488
 inet6_addr_add+0x589/0x960 net/ipv6/addrconf.c:3053
 inet6_rtm_newaddr+0x1619/0x1c70 net/ipv6/addrconf.c:5059
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6951
page last free pid 6091 tgid 6091 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2901
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:352
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4978 [inline]
 slab_alloc_node mm/slub.c:5288 [inline]
 kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5295
 anon_vma_chain_alloc mm/rmap.c:141 [inline]
 __anon_vma_prepare+0xae/0x5e0 mm/rmap.c:194
 __vmf_anon_prepare+0x11c/0x240 mm/memory.c:3634
 vmf_anon_prepare mm/internal.h:432 [inline]
 do_cow_fault mm/memory.c:5736 [inline]
 do_fault mm/memory.c:5852 [inline]
 do_pte_missing+0x8cd/0x3ba0 mm/memory.c:4362
 handle_pte_fault mm/memory.c:6195 [inline]
 __handle_mm_fault+0x1556/0x2aa0 mm/memory.c:6336
 handle_mm_fault+0x589/0xd10 mm/memory.c:6505
 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

Memory state around the buggy address:
 ffff88802cc7eb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802cc7eb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802cc7ec00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88802cc7ec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802cc7ed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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