================================================================== 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 ffff888050f77409 by task kworker/u32:22/12330 CPU: 0 UID: 0 PID: 12330 Comm: kworker/u32:22 Not tainted 6.14.0-syzkaller-10892-g4e82c87058f4 #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 12841: 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 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 12840: 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_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888050f77400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 9 bytes inside of freed 512-byte region [ffff888050f77400, ffff888050f77600) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x50f74 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 ffffea0001110c00 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b442c80 ffffea0001110c00 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea000143dd01 ffffffffffffffff 0000000000000000 head: ffff888000000004 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11133, tgid 11131 (syz.3.1956), ts 158160346312, free_ts 152625470173 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] __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4344 kmalloc_noprof include/linux/slab.h:902 [inline] kzalloc_noprof include/linux/slab.h:1036 [inline] rxrpc_alloc_peer+0xa7/0x400 net/rxrpc/peer_object.c:230 rxrpc_service_prealloc_one+0xb3d/0xee0 net/rxrpc/call_accept.c:74 rxrpc_kernel_charge_accept+0xd7/0x120 net/rxrpc/call_accept.c:475 afs_charge_preallocation+0xce/0x330 fs/afs/rxrpc.c:739 afs_open_socket+0x2b2/0x380 fs/afs/rxrpc.c:95 afs_net_init+0x746/0x9f0 fs/afs/main.c:115 ops_init+0x1df/0x5f0 net/core/net_namespace.c:138 setup_net+0x21e/0x850 net/core/net_namespace.c:364 page last free pid 15 tgid 15 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 pagetable_free include/linux/mm.h:2913 [inline] pagetable_dtor_free include/linux/mm.h:3011 [inline] __tlb_remove_table include/asm-generic/tlb.h:216 [inline] __tlb_remove_table_free mm/mmu_gather.c:227 [inline] tlb_remove_table_rcu+0x116/0x1a0 mm/mmu_gather.c:282 rcu_do_batch kernel/rcu/tree.c:2568 [inline] rcu_core+0x799/0x14e0 kernel/rcu/tree.c:2824 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579 run_ksoftirqd kernel/softirq.c:968 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960 smpboot_thread_fn+0x3f4/0xae0 kernel/smpboot.c:164 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 Memory state around the buggy address: ffff888050f77300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888050f77380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888050f77400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888050f77480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888050f77500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================