================================================================== BUG: KASAN: slab-out-of-bounds in scr_memcpyw include/linux/vt_buffer.h:38 [inline] BUG: KASAN: slab-out-of-bounds in fbcon_prepare_logo+0x94e/0xc60 drivers/video/fbdev/core/fbcon.c:686 Read of size 26 at addr ffff88801ff634ea by task syz.0.1987/15032 CPU: 0 UID: 0 PID: 15032 Comm: syz.0.1987 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1d0 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:686 fbcon_init+0x1065/0x1830 drivers/video/fbdev/core/fbcon.c:1228 visual_init+0x320/0x620 drivers/tty/vt/vt.c:1048 do_bind_con_driver.isra.0+0x636/0x9c0 drivers/tty/vt/vt.c:4056 vt_bind drivers/tty/vt/vt.c:4212 [inline] store_bind+0x609/0x730 drivers/tty/vt/vt.c:4284 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+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f70a659cdd9 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:00007f70a7446028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f70a6816270 RCX: 00007f70a659cdd9 RDX: 000000000008083a RSI: 00002000000000c0 RDI: 000000000000000b RBP: 00007f70a6632d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f70a6816308 R14: 00007f70a6816270 R15: 00007fff8fa042b8 Allocated by task 57: 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:5295 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5307 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] ext4_find_extent+0x21b/0xa30 fs/ext4/extents.c:918 ext4_ext_map_blocks+0x20a/0x5930 fs/ext4/extents.c:4286 ext4_map_create_blocks+0xec/0x5e0 fs/ext4/inode.c:631 ext4_map_blocks+0x46b/0xd30 fs/ext4/inode.c:824 mpage_map_one_extent fs/ext4/inode.c:2396 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2490 [inline] ext4_do_writepages+0x2313/0x3f20 fs/ext4/inode.c:2948 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3042 do_writepages+0x278/0x600 mm/page-writeback.c:2571 __writeback_single_inode+0x164/0x1350 fs/fs-writeback.c:1764 writeback_sb_inodes+0x766/0x1c60 fs/fs-writeback.c:2056 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2132 wb_writeback+0x720/0xb90 fs/fs-writeback.c:2243 wb_check_old_data_flush fs/fs-writeback.c:2347 [inline] wb_do_writeback fs/fs-writeback.c:2400 [inline] wb_workfn+0x8dd/0xc00 fs/fs-writeback.c:2428 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 57: 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:2689 [inline] slab_free mm/slub.c:6250 [inline] kfree+0x223/0x6c0 mm/slub.c:6565 ext4_free_ext_path+0xe4/0x120 fs/ext4/extents.c:127 ext4_ext_map_blocks+0x688/0x5930 fs/ext4/extents.c:4536 ext4_map_create_blocks+0xec/0x5e0 fs/ext4/inode.c:631 ext4_map_blocks+0x46b/0xd30 fs/ext4/inode.c:824 mpage_map_one_extent fs/ext4/inode.c:2396 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2490 [inline] ext4_do_writepages+0x2313/0x3f20 fs/ext4/inode.c:2948 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3042 do_writepages+0x278/0x600 mm/page-writeback.c:2571 __writeback_single_inode+0x164/0x1350 fs/fs-writeback.c:1764 writeback_sb_inodes+0x766/0x1c60 fs/fs-writeback.c:2056 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2132 wb_writeback+0x720/0xb90 fs/fs-writeback.c:2243 wb_check_old_data_flush fs/fs-writeback.c:2347 [inline] wb_do_writeback fs/fs-writeback.c:2400 [inline] wb_workfn+0x8dd/0xc00 fs/fs-writeback.c:2428 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88801ff63400 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 42 bytes to the right of allocated 192-byte region [ffff88801ff63400, ffff88801ff634c0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1ff63 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88813fe2e3c0 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 14094, tgid 14090 (syz.3.1783), ts 832691089779, free_ts 825118734165 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x11a6/0x33b0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x27c/0x2bc0 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab mm/slub.c:3467 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3525 refill_objects+0x277/0x420 mm/slub.c:7255 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x375/0x650 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __do_kmalloc_node mm/slub.c:5294 [inline] __kmalloc_noprof+0x688/0x850 mm/slub.c:5307 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] new_dir fs/proc/proc_sysctl.c:966 [inline] get_subdir fs/proc/proc_sysctl.c:1010 [inline] sysctl_mkdir_p fs/proc/proc_sysctl.c:1320 [inline] __register_sysctl_table+0xbe4/0x1650 fs/proc/proc_sysctl.c:1395 neigh_sysctl_register+0x326/0x660 net/core/neighbour.c:3922 addrconf_sysctl_register+0xb9/0x200 net/ipv6/addrconf.c:7379 ipv6_add_dev+0xaf2/0x1520 net/ipv6/addrconf.c:460 addrconf_notify+0x5db/0x1ba0 net/ipv6/addrconf.c:3662 notifier_call_chain+0x99/0x400 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2249 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] register_netdevice+0x18fe/0x24b0 net/core/dev.c:11458 register_netdev+0x34/0x50 net/core/dev.c:11536 page last free pid 5711 tgid 5711 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0x747/0x1040 mm/page_alloc.c:2943 kasan_depopulate_vmalloc_pte+0x5d/0x80 mm/kasan/shadow.c:484 apply_to_pte_range mm/memory.c:3322 [inline] apply_to_pmd_range mm/memory.c:3366 [inline] apply_to_pud_range mm/memory.c:3402 [inline] apply_to_p4d_range mm/memory.c:3438 [inline] __apply_to_page_range+0xb1d/0x1520 mm/memory.c:3474 __kasan_release_vmalloc+0xd7/0xe0 mm/kasan/shadow.c:602 kasan_release_vmalloc include/linux/kasan.h:593 [inline] kasan_release_vmalloc_node mm/vmalloc.c:2284 [inline] purge_vmap_node+0x210/0xb40 mm/vmalloc.c:2306 __purge_vmap_area_lazy+0x91b/0xc00 mm/vmalloc.c:2396 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: ffff88801ff63380: 00 00 00 04 fc fc fc fc fc fc fc fc fc fc fc fc ffff88801ff63400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801ff63480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ^ ffff88801ff63500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801ff63580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================