================================================================== BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x7d5/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1899 Read of size 1 at addr ffff88803dfa5009 by task kworker/u33:3/63 CPU: 2 UID: 0 PID: 63 Comm: kworker/u33:3 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:1899 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1895 [inline] drm_atomic_helper_commit_tail+0xff/0x130 drivers/gpu/drm/drm_atomic_helper.c:1997 commit_tail+0x338/0x430 drivers/gpu/drm/drm_atomic_helper.c:2074 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387 process_scheduled_works kernel/workqueue.c:3470 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551 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 11544: 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+0x2e7/0x6b0 mm/slub.c:5484 _kmalloc_noprof include/linux/slab.h:988 [inline] drm_atomic_helper_crtc_duplicate_state+0x72/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:179 drm_atomic_get_crtc_state+0x1de/0x690 drivers/gpu/drm/drm_atomic.c:382 page_flip_common+0x59/0x320 drivers/gpu/drm/drm_atomic_helper.c:3941 drm_atomic_helper_page_flip+0xb6/0x180 drivers/gpu/drm/drm_atomic_helper.c:4002 drm_mode_page_flip_ioctl+0x1095/0x14a0 drivers/gpu/drm/drm_plane.c:1543 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 11543: 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:2678 [inline] slab_free mm/slub.c:6372 [inline] kfree+0x22b/0x6c0 mm/slub.c:6687 drm_atomic_commit_default_clear+0x465/0x10c0 drivers/gpu/drm/drm_atomic.c:231 drm_atomic_commit_clear drivers/gpu/drm/drm_atomic.c:314 [inline] __drm_atomic_commit_free+0x185/0x2f0 drivers/gpu/drm/drm_atomic.c:331 kref_put include/linux/kref.h:65 [inline] drm_atomic_commit_put include/drm/drm_atomic.h:710 [inline] drm_client_modeset_commit_atomic+0x5f3/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1110 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1207 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1233 __drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x137/0x160 drivers/gpu/drm/drm_fb_helper.c:138 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:126 [inline] drm_fb_helper_restore_fbdev_mode_unlocked+0x93/0xc0 drivers/gpu/drm/drm_fb_helper.c:169 drm_fbdev_client_restore+0x1b/0x30 drivers/gpu/drm/clients/drm_fbdev_client.c:45 drm_client_dev_restore+0x205/0x2a0 drivers/gpu/drm/drm_client_event.c:118 drm_lastclose drivers/gpu/drm/drm_file.c:408 [inline] drm_release+0x2c6/0x360 drivers/gpu/drm/drm_file.c:441 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x1d8/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803dfa5000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 9 bytes inside of freed 512-byte region [ffff88803dfa5000, ffff88803dfa5200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3dfa4 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 0000000800100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801c042c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 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 5721, tgid 5721 (syz-executor), ts 54896185224 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/0x35b0 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3267 [inline] allocate_slab mm/slub.c:3382 [inline] new_slab+0xa5/0x640 mm/slub.c:3428 refill_objects+0xe3/0x410 mm/slub.c:7305 refill_sheaf mm/slub.c:2805 [inline] __pcs_replace_empty_main+0x372/0x680 mm/slub.c:4677 alloc_from_pcs mm/slub.c:4775 [inline] slab_alloc_node mm/slub.c:4907 [inline] __kmalloc_cache_noprof+0x47b/0x6b0 mm/slub.c:5480 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] mca_alloc net/ipv6/mcast.c:871 [inline] __ipv6_dev_mc_inc+0x2f1/0xbd0 net/ipv6/mcast.c:962 ipv6_add_dev+0xb78/0x1520 net/ipv6/addrconf.c:472 ipv6_find_idev+0x192/0x1f0 net/ipv6/addrconf.c:498 inet6_rtm_newaddr+0x561/0x1bb0 net/ipv6/addrconf.c:5073 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:7132 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:800 [inline] __sock_sendmsg net/socket.c:815 [inline] __sys_sendto+0x48b/0x4e0 net/socket.c:2281 page last free pid 5722 tgid 5722 ts 54863892551 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x79f/0x10f0 mm/page_alloc.c:2962 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4586 [inline] slab_alloc_node mm/slub.c:4919 [inline] kmem_cache_alloc_lru_noprof+0x267/0x6a0 mm/slub.c:4952 sock_alloc_inode+0x26/0x2c0 net/socket.c:330 alloc_inode+0x68/0x250 fs/inode.c:338 new_inode_pseudo include/linux/fs.h:3045 [inline] sock_alloc+0x44/0x280 net/socket.c:710 __sock_create+0xc2/0x860 net/socket.c:1640 sock_create net/socket.c:1734 [inline] __sys_socket_create net/socket.c:1771 [inline] __sys_socket+0x14d/0x260 net/socket.c:1818 __do_sys_socket net/socket.c:1832 [inline] __se_sys_socket net/socket.c:1830 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1830 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 Memory state around the buggy address: ffff88803dfa4f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803dfa4f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88803dfa5000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803dfa5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803dfa5100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================