================================================================== 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 ffff888026599809 by task kworker/u32:7/1140 CPU: 3 UID: 0 PID: 1140 Comm: kworker/u32:7 Not tainted 6.14.0-syzkaller-13183-g06a22366d6a1 #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 9792: 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:905 [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 9790: 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:2389 [inline] slab_free mm/slub.c:4646 [inline] kfree+0x2b6/0x4d0 mm/slub.c:4845 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 ffff888026599800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 9 bytes inside of freed 512-byte region [ffff888026599800, ffff888026599a00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26598 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 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b442c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea0000996601 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 6749, tgid 6749 (udevd), ts 168868581566, free_ts 166891018623 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1717 prep_new_page mm/page_alloc.c:1725 [inline] get_page_from_freelist+0x1193/0x39b0 mm/page_alloc.c:3652 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4934 alloc_slab_page mm/slub.c:2461 [inline] allocate_slab mm/slub.c:2623 [inline] new_slab+0x94/0x330 mm/slub.c:2676 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3862 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3952 __slab_alloc_node mm/slub.c:4027 [inline] slab_alloc_node mm/slub.c:4188 [inline] __do_kmalloc_node mm/slub.c:4330 [inline] __kmalloc_node_noprof+0x2ed/0x500 mm/slub.c:4337 kmalloc_array_node_noprof include/linux/slab.h:1020 [inline] alloc_slab_obj_exts+0x41/0xa0 mm/slub.c:1987 account_slab mm/slub.c:2586 [inline] allocate_slab mm/slub.c:2641 [inline] new_slab+0x284/0x330 mm/slub.c:2676 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3862 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3952 __slab_alloc_node mm/slub.c:4027 [inline] slab_alloc_node mm/slub.c:4188 [inline] kmem_cache_alloc_noprof+0xef/0x3b0 mm/slub.c:4207 sigqueue_alloc kernel/signal.c:455 [inline] __send_signal_locked+0x159/0x12c0 kernel/signal.c:1087 do_send_sig_info kernel/signal.c:1269 [inline] group_send_sig_info+0x2a4/0x300 kernel/signal.c:1419 do_bpf_send_signal+0xe1/0x210 kernel/trace/bpf_trace.c:815 irq_work_single+0x1bc/0x260 kernel/irq_work.c:221 page last free pid 5952 tgid 5952 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2680 discard_slab mm/slub.c:2720 [inline] __put_partials+0x16d/0x1c0 mm/slub.c:3189 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/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:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4151 [inline] slab_alloc_node mm/slub.c:4200 [inline] kmem_cache_alloc_node_noprof+0x1d5/0x3b0 mm/slub.c:4252 alloc_task_struct_node kernel/fork.c:180 [inline] dup_task_struct kernel/fork.c:1128 [inline] copy_process+0x4bd/0x91a0 kernel/fork.c:2259 kernel_clone+0xfc/0x960 kernel/fork.c:2844 __do_compat_sys_ia32_clone+0xcb/0x110 arch/x86/kernel/sys_ia32.c:254 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 Memory state around the buggy address: ffff888026599700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888026599780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888026599800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888026599880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888026599900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================