================================================================== BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks+0x367/0x980 drivers/gpu/drm/drm_atomic_helper.c:1815 Read of size 1 at addr ffff8880402a3809 by task kworker/u4:3/43 CPU: 0 UID: 0 PID: 43 Comm: kworker/u4:3 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: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 drm_atomic_helper_wait_for_vblanks+0x367/0x980 drivers/gpu/drm/drm_atomic_helper.c:1815 drm_atomic_helper_commit_tail+0x302/0x520 drivers/gpu/drm/drm_atomic_helper.c:1911 commit_tail+0x29a/0x3a0 drivers/gpu/drm/drm_atomic_helper.c:1988 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5354: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4407 kmalloc_noprof include/linux/slab.h:905 [inline] drm_atomic_helper_crtc_duplicate_state+0x72/0xb0 drivers/gpu/drm/drm_atomic_state_helper.c:178 drm_atomic_get_crtc_state+0x19a/0x460 drivers/gpu/drm/drm_atomic.c:360 page_flip_common+0x56/0x2a0 drivers/gpu/drm/drm_atomic_helper.c:3832 drm_atomic_helper_page_flip+0xa5/0x160 drivers/gpu/drm/drm_atomic_helper.c:3893 drm_mode_page_flip_ioctl+0xc6d/0x11d0 drivers/gpu/drm/drm_plane.c:1543 drm_ioctl_kernel+0x2cf/0x390 drivers/gpu/drm/drm_ioctl.c:796 drm_ioctl+0x67f/0xb10 drivers/gpu/drm/drm_ioctl.c:893 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5354: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kfree+0x18e/0x440 mm/slub.c:4894 drm_atomic_state_default_clear+0x41f/0xbe0 drivers/gpu/drm/drm_atomic.c:224 drm_atomic_state_clear drivers/gpu/drm/drm_atomic.c:293 [inline] __drm_atomic_state_free+0xaf/0x210 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+0x6ac/0x760 drivers/gpu/drm/drm_client_modeset.c:1109 drm_client_modeset_commit_locked+0xcb/0x4d0 drivers/gpu/drm/drm_client_modeset.c:1206 drm_client_modeset_commit+0x4a/0x70 drivers/gpu/drm/drm_client_modeset.c:1232 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:238 [inline] drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:268 [inline] drm_fb_helper_lastclose+0xa4/0x1c0 drivers/gpu/drm/drm_fb_helper.c:1986 drm_fbdev_client_restore+0x34/0x40 drivers/gpu/drm/clients/drm_fbdev_client.c:31 drm_client_dev_restore+0x13c/0x270 drivers/gpu/drm/drm_client_event.c:117 drm_lastclose drivers/gpu/drm/drm_file.c:408 [inline] drm_release+0x318/0x3f0 drivers/gpu/drm/drm_file.c:441 __fput+0x449/0xa70 fs/file_table.c:468 task_work_run+0x1d1/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x1286/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40 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+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880402a3800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 9 bytes inside of freed 512-byte region [ffff8880402a3800, ffff8880402a3a00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x402a2 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 ksm flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff88801a441c80 ffffea000100a980 dead000000000003 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 04fff00000000040 ffff88801a441c80 ffffea000100a980 dead000000000003 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 04fff00000000001 ffffea000100a881 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5049, tgid 5049 (dhcpcd), ts 44480976763, free_ts 43599720454 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2492 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2660 new_slab mm/slub.c:2714 [inline] ___slab_alloc+0xbeb/0x1420 mm/slub.c:3901 __slab_alloc mm/slub.c:3992 [inline] __slab_alloc_node mm/slub.c:4067 [inline] slab_alloc_node mm/slub.c:4228 [inline] __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4402 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] device_private_init drivers/base/core.c:3534 [inline] device_add+0xbe/0xb50 drivers/base/core.c:3585 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2356 register_netdevice+0x126c/0x1ae0 net/core/dev.c:11206 lapbeth_new_device drivers/net/wan/lapbether.c:420 [inline] lapbeth_device_event+0x829/0xae0 drivers/net/wan/lapbether.c:462 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] __dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9617 dev_change_flags+0x130/0x260 net/core/dev_api.c:68 devinet_ioctl+0xbb4/0x1b50 net/ipv4/devinet.c:1199 page last free pid 5097 tgid 5097 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895 __slab_free+0x303/0x3c0 mm/slub.c:4606 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4247 vm_area_alloc+0x24/0x140 mm/vma_init.c:31 __mmap_new_vma mm/vma.c:2461 [inline] __mmap_region mm/vma.c:2669 [inline] mmap_region+0xdc7/0x20c0 mm/vma.c:2739 do_mmap+0xc45/0x10d0 mm/mmap.c:558 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:580 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880402a3700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880402a3780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880402a3800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880402a3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880402a3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================