================================================================== BUG: KASAN: slab-use-after-free in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-use-after-free in fbcon_prepare_logo+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646 Read of size 26 at addr ffff88802aabd38e by task syz.0.3072/19801 CPU: 0 UID: 0 PID: 19801 Comm: syz.0.3072 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:186 [inline] kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105 scr_memcpyw include/linux/vt_buffer.h:38 [inline] fbcon_prepare_logo+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:646 fbcon_init+0x10a0/0x1820 drivers/video/fbdev/core/fbcon.c:1180 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1014 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3954 vt_bind drivers/tty/vt/vt.c:4110 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4182 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fed0d19c799 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fed0e0a2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fed0d416090 RCX: 00007fed0d19c799 RDX: 000000000000fdef RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007fed0d232c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fed0d416128 R14: 00007fed0d416090 R15: 00007ffc5a8717c8 Allocated by task 19801: 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 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] drm_atomic_state_alloc drivers/gpu/drm/drm_atomic.c:178 [inline] drm_atomic_state_alloc+0xb8/0x120 drivers/gpu/drm/drm_atomic.c:171 drm_client_modeset_commit_atomic+0xcc/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1045 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:137 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:1177 [inline] drm_fb_helper_set_par+0x15a/0x1b0 drivers/gpu/drm/drm_fb_helper.c:1179 fbcon_init+0x139c/0x1820 drivers/video/fbdev/core/fbcon.c:1147 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1014 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3954 vt_bind drivers/tty/vt/vt.c:4110 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4182 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 19801: 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:2692 [inline] slab_free mm/slub.c:6168 [inline] kfree+0x1f6/0x6b0 mm/slub.c:6486 __drm_atomic_state_free+0x25b/0x2f0 drivers/gpu/drm/drm_atomic.c:339 kref_put include/linux/kref.h:65 [inline] drm_atomic_state_put include/drm/drm_atomic.h:697 [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:137 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:1177 [inline] drm_fb_helper_set_par+0x15a/0x1b0 drivers/gpu/drm/drm_fb_helper.c:1179 fbcon_init+0x139c/0x1820 drivers/video/fbdev/core/fbcon.c:1147 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1014 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:3954 vt_bind drivers/tty/vt/vt.c:4110 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4182 dev_attr_store+0x58/0x80 drivers/base/core.c:2437 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:688 ksys_write+0x12a/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802aabd300 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 142 bytes inside of freed 192-byte region [ffff88802aabd300, ffff88802aabd3c0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2aabd flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe3c3c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 9588422799, free_ts 9538037392 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3296 [inline] allocate_slab mm/slub.c:3485 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3543 refill_objects+0x26b/0x400 mm/slub.c:7178 refill_sheaf mm/slub.c:2818 [inline] alloc_full_sheaf mm/slub.c:2839 [inline] __pcs_replace_empty_main+0x1ab/0x600 mm/slub.c:4629 alloc_from_pcs mm/slub.c:4720 [inline] slab_alloc_node mm/slub.c:4854 [inline] __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5378 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] call_usermodehelper_setup+0xaf/0x360 kernel/umh.c:362 kobject_uevent_env+0x17c1/0x18b0 lib/kobject_uevent.c:628 device_add+0x116e/0x1950 drivers/base/core.c:3670 device_create_groups_vargs+0x1f8/0x270 drivers/base/core.c:4371 device_create+0xed/0x130 drivers/base/core.c:4410 mon_bin_add+0xba/0x160 drivers/usb/mon/mon_bin.c:1371 mon_bus_init+0x18e/0x320 drivers/usb/mon/mon_main.c:291 mon_bus_add drivers/usb/mon/mon_main.c:188 [inline] mon_notify+0x31c/0x480 drivers/usb/mon/mon_main.c:219 notifier_call_chain+0x99/0x420 kernel/notifier.c:85 page last free pid 24 tgid 24 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 vfree.part.0+0x12b/0x9d0 mm/vmalloc.c:3479 vfree mm/vmalloc.c:3456 [inline] delayed_vfree_work+0x8e/0xd0 mm/vmalloc.c:3398 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88802aabd280: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ffff88802aabd300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802aabd380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802aabd400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88802aabd480: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================