================================================================== BUG: KASAN: slab-use-after-free in soft_cursor+0x378/0x6bc drivers/video/fbdev/core/softcursor.c:70 Read of size 70 at addr ffff0000dbc7c9d6 by task syz.3.264/5822 CPU: 0 UID: 0 PID: 5822 Comm: syz.3.264 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xb0/0x238 mm/kasan/report.c:378 print_report+0x68/0x84 mm/kasan/report.c:482 kasan_report+0x8c/0xc4 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x17c/0x1ac mm/kasan/generic.c:200 __asan_memcpy+0x3c/0x84 mm/kasan/shadow.c:105 soft_cursor+0x378/0x6bc drivers/video/fbdev/core/softcursor.c:70 cw_cursor+0xb18/0x11e4 drivers/video/fbdev/core/fbcon_cw.c:324 fbcon_cursor+0x344/0x498 drivers/video/fbdev/core/fbcon.c:1427 hide_cursor+0xdc/0x2d0 drivers/tty/vt/vt.c:883 redraw_screen+0x200/0x51c drivers/tty/vt/vt.c:985 vc_do_resize+0x884/0xbbc drivers/tty/vt/vt.c:1309 __vc_resize+0x60/0x74 drivers/tty/vt/vt.c:1331 vc_resize include/linux/vt_kern.h:49 [inline] fbcon_do_set_font+0x3d8/0x734 drivers/video/fbdev/core/fbcon.c:2435 fbcon_set_font+0x4f0/0x6ac drivers/video/fbdev/core/fbcon.c:2518 con_font_set drivers/tty/vt/vt.c:4992 [inline] con_font_op+0x98c/0xc6c drivers/tty/vt/vt.c:5032 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:472 [inline] vt_ioctl+0x1724/0x1e0c drivers/tty/vt/vt_ioctl.c:743 tty_ioctl+0x880/0xd50 drivers/tty/tty_io.c:2792 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 Allocated by task 4704: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:570 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x340/0x6b8 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] tomoyo_realpath_from_path+0xbc/0x4dc security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x218/0x460 security/tomoyo/file.c:827 tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123 security_inode_getattr+0x114/0x2c0 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_statx_path+0x34/0x22c fs/stat.c:299 vfs_statx+0x124/0x1d8 fs/stat.c:356 vfs_fstatat+0xa4/0xd0 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __arm64_sys_newfstatat+0x134/0x1c8 fs/stat.c:532 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 Freed by task 4704: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x74/0xa4 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x188/0x690 mm/slub.c:6692 tomoyo_realpath_from_path+0x494/0x4dc security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x218/0x460 security/tomoyo/file.c:827 tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123 security_inode_getattr+0x114/0x2c0 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_statx_path+0x34/0x22c fs/stat.c:299 vfs_statx+0x124/0x1d8 fs/stat.c:356 vfs_fstatat+0xa4/0xd0 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __arm64_sys_newfstatat+0x134/0x1c8 fs/stat.c:532 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 The buggy address belongs to the object at ffff0000dbc7c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 2518 bytes inside of freed 4096-byte region [ffff0000dbc7c000, ffff0000dbc7d000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11bc78 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000040 ffff0000c0002140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0002140 dead000000000100 dead000000000122 head: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 05ffc00000000003 fffffdffc36f1e01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000dbc7c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000dbc7c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000dbc7c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000dbc7ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000dbc7ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================