================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:646 [inline] BUG: KASAN: slab-out-of-bounds in fb_pad_aligned_buffer+0xe4/0x138 drivers/video/fbdev/core/fbmem.c:96 Read of size 1 at addr ffff0000c4e6d200 by task syz.1.41/5055 CPU: 1 UID: 0 PID: 5055 Comm: syz.1.41 Not tainted syzkaller #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026 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 __asan_report_load1_noabort+0x20/0x2c mm/kasan/report_generic.c:378 __fb_pad_aligned_buffer include/linux/fb.h:646 [inline] fb_pad_aligned_buffer+0xe4/0x138 drivers/video/fbdev/core/fbmem.c:96 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:105 [inline] cw_putcs+0x5d8/0x8bc drivers/video/fbdev/core/fbcon_cw.c:159 fbcon_putcs+0x258/0x390 drivers/video/fbdev/core/fbcon.c:1392 con_putc drivers/tty/vt/vt.c:330 [inline] hide_softcursor drivers/tty/vt/vt.c:872 [inline] hide_cursor+0x220/0x2d0 drivers/tty/vt/vt.c:884 redraw_screen+0x200/0x51c drivers/tty/vt/vt.c:985 fbcon_do_set_font+0x4e4/0x734 drivers/video/fbdev/core/fbcon.c:2441 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:474 [inline] vt_ioctl+0x1664/0x1d4c drivers/tty/vt/vt_ioctl.c:745 tty_ioctl+0x828/0xcb0 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:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 Allocated by task 4881: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:78 kasan_save_alloc_info+0x40/0x50 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] _kmalloc_array_noprof include/linux/slab.h:1208 [inline] font_data_rotate+0x100/0x2f0 lib/fonts/font_rotate.c:231 fbcon_rotate_font+0x218/0x374 drivers/video/fbdev/core/fbcon_rotate.c:33 fbcon_modechanged+0x19c/0x698 drivers/video/fbdev/core/fbcon.c:2664 fbcon_rotate drivers/video/fbdev/core/fbcon.c:230 [inline] rotate_store+0x1f4/0x334 drivers/video/fbdev/core/fbcon.c:3196 dev_attr_store+0x6c/0x90 drivers/base/core.c:2505 sysfs_kf_write+0xe0/0x108 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x260/0x3b8 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x51c/0xa0c fs/read_write.c:687 ksys_write+0x12c/0x228 fs/read_write.c:739 __do_sys_write fs/read_write.c:750 [inline] __se_sys_write fs/read_write.c:747 [inline] __arm64_sys_write+0x84/0x98 fs/read_write.c:747 __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:758 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590 The buggy address belongs to the object at ffff0000c4e6c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 512 bytes to the right of allocated 4096-byte region [ffff0000c4e6c000, ffff0000c4e6d000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x104e68 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 dead000000000122 0000000000000000 raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0002140 dead000000000122 0000000000000000 head: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000 head: 05ffc00000000003 fffffdffc3139a01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c4e6d100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000c4e6d180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000c4e6d200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff0000c4e6d280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000c4e6d300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================