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:00007f34101d5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f3412216180 RCX: 00007f3411f9c799 RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007f3412032c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3412216218 R14: 00007f3412216180 R15: 00007ffe19549d08 ================================================================== 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 8 at addr ffff88802b67aaa2 by task syz.6.4345/26709 CPU: 0 UID: 0 PID: 26709 Comm: syz.6.4345 Tainted: G U L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026 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: 0033:0x7f3411f9c799 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:00007f34101d5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f3412216180 RCX: 00007f3411f9c799 RDX: 0000000000000084 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007f3412032c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3412216218 R14: 00007f3412216180 R15: 00007ffe19549d08 Allocated by task 26709: 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 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5263 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5275 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] drm_atomic_state_init+0x190/0x490 drivers/gpu/drm/drm_atomic.c:138 drm_atomic_state_alloc drivers/gpu/drm/drm_atomic.c:181 [inline] drm_atomic_state_alloc+0xd3/0x120 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 fb_set_var+0x824/0x11b0 drivers/video/fbdev/core/fbmem.c:319 fbcon_switch+0x9b3/0x1a00 drivers/video/fbdev/core/fbcon.c:2152 redraw_screen+0x2c1/0x760 drivers/tty/vt/vt.c:960 vc_do_resize+0xe1a/0x10f0 drivers/tty/vt/vt.c:1275 vc_resize include/linux/vt_kern.h:49 [inline] fbcon_init+0x10ba/0x1820 drivers/video/fbdev/core/fbcon.c:1177 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 26709: 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_default_release drivers/gpu/drm/drm_atomic.c:110 [inline] __drm_atomic_state_free+0x207/0x2f0 drivers/gpu/drm/drm_atomic.c:338 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 fb_set_var+0x824/0x11b0 drivers/video/fbdev/core/fbmem.c:319 fbcon_switch+0x9b3/0x1a00 drivers/video/fbdev/core/fbcon.c:2152 redraw_screen+0x2c1/0x760 drivers/tty/vt/vt.c:960 vc_do_resize+0xe1a/0x10f0 drivers/tty/vt/vt.c:1275 vc_resize include/linux/vt_kern.h:49 [inline] fbcon_init+0x10ba/0x1820 drivers/video/fbdev/core/fbcon.c:1177 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 ffff88802b67aa80 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 34 bytes inside of freed 64-byte region [ffff88802b67aa80, ffff88802b67aac0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b67a flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe3c8c0 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800200020 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 1313, tgid 1313 (kworker/u8:8), ts 12817484610, free_ts 12817408535 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] __do_kmalloc_node mm/slub.c:5262 [inline] __kmalloc_node_noprof+0x69a/0x850 mm/slub.c:5269 kmalloc_node_noprof include/linux/slab.h:1081 [inline] __vmalloc_area_node mm/vmalloc.c:3855 [inline] __vmalloc_node_range_noprof+0x3dc/0x1530 mm/vmalloc.c:4064 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:355 [inline] dup_task_struct kernel/fork.c:924 [inline] copy_process+0x5ec/0x7a10 kernel/fork.c:2050 kernel_clone+0xfc/0x9a0 kernel/fork.c:2654 user_mode_thread+0xcc/0x110 kernel/fork.c:2730 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:157 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 page last free pid 1313 tgid 1313 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 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline] __kasan_populate_vmalloc+0x1ea/0x210 mm/kasan/shadow.c:424 kasan_populate_vmalloc include/linux/kasan.h:580 [inline] alloc_vmap_area+0x95d/0x2bd0 mm/vmalloc.c:2129 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3232 __vmalloc_node_range_noprof+0x213/0x1530 mm/vmalloc.c:4024 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4124 alloc_thread_stack_node kernel/fork.c:355 [inline] dup_task_struct kernel/fork.c:924 [inline] copy_process+0x5ec/0x7a10 kernel/fork.c:2050 kernel_clone+0xfc/0x9a0 kernel/fork.c:2654 user_mode_thread+0xcc/0x110 kernel/fork.c:2730 call_usermodehelper_exec_work kernel/umh.c:171 [inline] call_usermodehelper_exec_work+0xcb/0x180 kernel/umh.c:157 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: ffff88802b67a980: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ffff88802b67aa00: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc >ffff88802b67aa80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88802b67ab00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ffff88802b67ab80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess): 0: ff c3 inc %ebx 2: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) 9: 00 00 00 c: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 11: 48 89 f8 mov %rdi,%rax 14: 48 89 f7 mov %rsi,%rdi 17: 48 89 d6 mov %rdx,%rsi 1a: 48 89 ca mov %rcx,%rdx 1d: 4d 89 c2 mov %r8,%r10 20: 4d 89 c8 mov %r9,%r8 23: 4c 8b 4c 24 08 mov 0x8(%rsp),%r9 28: 0f 05 syscall * 2a: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction 30: 73 01 jae 0x33 32: c3 ret 33: 48 c7 c1 e8 ff ff ff mov $0xffffffffffffffe8,%rcx 3a: f7 d8 neg %eax 3c: 64 89 01 mov %eax,%fs:(%rcx) 3f: 48 rex.W