================================================================== BUG: KASAN: slab-use-after-free in drm_atomic_helper_wait_for_vblanks.part.0+0x8c0/0x9b0 drivers/gpu/drm/drm_atomic_helper.c:1700 Read of size 1 at addr ffff888050373009 by task kworker/u32:6/29414 CPU: 0 UID: 0 PID: 29414 Comm: kworker/u32:6 Not tainted 6.14.0-syzkaller-11270-g08733088b566 #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 lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 drm_atomic_helper_wait_for_vblanks.part.0+0x8c0/0x9b0 drivers/gpu/drm/drm_atomic_helper.c:1700 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1696 [inline] drm_atomic_helper_commit_tail+0xcb/0xf0 drivers/gpu/drm/drm_atomic_helper.c:1796 commit_tail+0x35b/0x400 drivers/gpu/drm/drm_atomic_helper.c:1873 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 32643: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:902 [inline] drm_atomic_helper_crtc_duplicate_state+0x70/0xd0 drivers/gpu/drm/drm_atomic_state_helper.c:177 drm_atomic_get_crtc_state+0x16e/0x450 drivers/gpu/drm/drm_atomic.c:360 drm_atomic_get_plane_state+0x436/0x590 drivers/gpu/drm/drm_atomic.c:561 drm_atomic_set_property+0xa29/0x34e0 drivers/gpu/drm/drm_atomic_uapi.c:1073 drm_mode_atomic_ioctl+0x66f/0x25f0 drivers/gpu/drm/drm_atomic_uapi.c:1514 drm_ioctl_kernel+0x1f1/0x3e0 drivers/gpu/drm/drm_ioctl.c:796 drm_ioctl+0x5c9/0xc30 drivers/gpu/drm/drm_ioctl.c:893 drm_compat_ioctl+0x327/0x460 drivers/gpu/drm/drm_ioc32.c:379 __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 32642: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2376 [inline] slab_free mm/slub.c:4633 [inline] kfree+0x2b6/0x4d0 mm/slub.c:4832 drm_atomic_state_default_clear+0x455/0xe40 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:1085 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1182 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1208 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:237 [inline] __drm_fb_helper_restore_fbdev_mode_unlocked+0x19f/0x200 drivers/gpu/drm/drm_fb_helper.c:216 drm_fbdev_client_restore+0x2c/0x40 drivers/gpu/drm/clients/drm_fbdev_client.c:31 drm_client_dev_restore+0x1f3/0x2a0 drivers/gpu/drm/drm_client_event.c:116 drm_lastclose drivers/gpu/drm/drm_file.c:396 [inline] drm_release+0x2c4/0x360 drivers/gpu/drm/drm_file.c:429 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/syscall_32.c:309 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff888050373000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 9 bytes inside of freed 512-byte region [ffff888050373000, ffff888050373200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x50370 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff88801b442c80 ffffea000144c900 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 04fff00000000040 ffff88801b442c80 ffffea000144c900 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 04fff00000000002 ffffea000140dc01 ffffffffffffffff 0000000000000000 head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 8587, tgid 8587 (kworker/u32:2), ts 3136304718580, free_ts 3134911107771 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1585 prep_new_page mm/page_alloc.c:1593 [inline] get_page_from_freelist+0x10fc/0x35c0 mm/page_alloc.c:3538 __alloc_frozen_pages_noprof+0x223/0x2370 mm/page_alloc.c:4806 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2446 [inline] allocate_slab mm/slub.c:2610 [inline] new_slab+0x23c/0x330 mm/slub.c:2663 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3849 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3939 __slab_alloc_node mm/slub.c:4014 [inline] slab_alloc_node mm/slub.c:4175 [inline] __do_kmalloc_node mm/slub.c:4317 [inline] __kmalloc_noprof+0x2f2/0x510 mm/slub.c:4330 kmalloc_noprof include/linux/slab.h:906 [inline] kzalloc_noprof include/linux/slab.h:1036 [inline] fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x33f/0x18e0 net/ipv6/route.c:3767 ip6_route_add+0x26/0x1c0 net/ipv6/route.c:3861 addrconf_prefix_route+0x2fd/0x510 net/ipv6/addrconf.c:2485 addrconf_add_linklocal+0x329/0x500 net/ipv6/addrconf.c:3310 addrconf_addr_gen+0x36d/0x3c0 net/ipv6/addrconf.c:3439 addrconf_dev_config net/ipv6/addrconf.c:3485 [inline] addrconf_init_auto_addrs+0x446/0x820 net/ipv6/addrconf.c:3563 addrconf_notify+0x6e2/0x19e0 net/ipv6/addrconf.c:3736 page last free pid 2513 tgid 2513 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1130 [inline] __free_frozen_pages+0x69d/0xf90 mm/page_alloc.c:2707 vfree+0x176/0x960 mm/vmalloc.c:3383 kcov_put kernel/kcov.c:439 [inline] kcov_put kernel/kcov.c:435 [inline] kcov_close+0x34/0x60 kernel/kcov.c:535 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xafe/0x2d90 kernel/exit.c:954 do_group_exit+0xd3/0x2a0 kernel/exit.c:1103 get_signal+0x2673/0x26d0 kernel/signal.c:3035 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/syscall_32.c:309 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Memory state around the buggy address: ffff888050372f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888050372f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888050373000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888050373080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888050373100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================