================================================================== BUG: KASAN: global-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:645 [inline] BUG: KASAN: global-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:95 [inline] BUG: KASAN: global-out-of-bounds in bit_putcs+0xa63/0xde0 drivers/video/fbdev/core/bitblit.c:184 Read of size 1 at addr ffffffff8bf7909a by task syz.1.1555/11545 CPU: 3 UID: 0 PID: 11545 Comm: syz.1.1555 Not tainted 6.15.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 __fb_pad_aligned_buffer include/linux/fb.h:645 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:95 [inline] bit_putcs+0xa63/0xde0 drivers/video/fbdev/core/bitblit.c:184 fbcon_putcs+0x383/0x4a0 drivers/video/fbdev/core/fbcon.c:1309 con_flush drivers/tty/vt/vt.c:2762 [inline] do_con_write+0xefe/0x7c90 drivers/tty/vt/vt.c:3091 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3432 process_output_block drivers/tty/n_tty.c:561 [inline] n_tty_write+0x40f/0x1160 drivers/tty/n_tty.c:2377 iterate_tty_write drivers/tty/tty_io.c:1015 [inline] file_tty_write.constprop.0+0x502/0x9b0 drivers/tty/tty_io.c:1090 new_sync_write fs/read_write.c:591 [inline] vfs_write+0x5ba/0x1180 fs/read_write.c:684 ksys_write+0x12a/0x240 fs/read_write.c:736 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f17579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f503655c EFLAGS: 00000296 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000080000000 RDX: 0000000000001006 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the variable: type_check_kinds+0x65a/0xa80 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xbf79 flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000002000 ffffea00002fde48 ffffea00002fde48 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?) Memory state around the buggy address: ffffffff8bf78f80: 00 00 06 f9 f9 f9 f9 f9 00 00 01 f9 f9 f9 f9 f9 ffffffff8bf79000: 00 06 f9 f9 f9 f9 f9 f9 00 00 07 f9 f9 f9 f9 f9 >ffffffff8bf79080: 00 00 00 02 f9 f9 f9 f9 00 00 01 f9 f9 f9 f9 f9 ^ ffffffff8bf79100: 00 00 00 02 f9 f9 f9 f9 05 f9 f9 f9 f9 f9 f9 f9 ffffffff8bf79180: 05 f9 f9 f9 f9 f9 f9 f9 05 f9 f9 f9 f9 f9 f9 f9 ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi