================================================================== BUG: KASAN: global-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:644 [inline] BUG: KASAN: global-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: global-out-of-bounds in bit_putcs+0xa64/0xdf0 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffffffff8bd640d0 by task syz.2.2226/15520 CPU: 2 UID: 0 PID: 15520 Comm: syz.2.2226 Not tainted 6.14.0-rc5-syzkaller-00016-g48a5eed9ad58 #0 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+0xd9/0x110 mm/kasan/report.c:634 __fb_pad_aligned_buffer include/linux/fb.h:644 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xa64/0xdf0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x364/0x480 drivers/video/fbdev/core/fbcon.c:1308 do_update_region+0x1f8/0x3f0 drivers/tty/vt/vt.c:609 update_region+0xc1/0x160 drivers/tty/vt/vt.c:633 vcs_write+0x7cd/0xdb0 drivers/tty/vt/vc_screen.c:698 do_loop_readv_writev fs/read_write.c:843 [inline] do_loop_readv_writev fs/read_write.c:828 [inline] vfs_writev+0x6da/0xdd0 fs/read_write.c:1052 do_writev+0x133/0x340 fs/read_write.c:1096 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:387 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:412 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f27579 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:00000000f504655c EFLAGS: 00000296 ORIG_RAX: 0000000000000092 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000a40 RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the variable: type_check_kinds+0x790/0xad0 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xbd64 flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000002000 ffffea00002f5908 ffffea00002f5908 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: ffffffff8bd63f80: 00 00 00 02 f9 f9 f9 f9 00 00 01 f9 f9 f9 f9 f9 ffffffff8bd64000: 00 00 00 02 f9 f9 f9 f9 05 f9 f9 f9 f9 f9 f9 f9 >ffffffff8bd64080: 05 f9 f9 f9 f9 f9 f9 f9 05 f9 f9 f9 f9 f9 f9 f9 ^ ffffffff8bd64100: 05 f9 f9 f9 f9 f9 f9 f9 00 00 00 00 06 f9 f9 f9 ffffffff8bd64180: f9 f9 f9 f9 00 00 00 00 00 00 01 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