================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:654 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] BUG: KASAN: slab-out-of-bounds in bit_putcs+0x103a/0x1bf0 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88809edb2f97 by task syz-executor.5/3656 CPU: 0 PID: 3656 Comm: syz-executor.5 Not tainted 5.9.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 __fb_pad_aligned_buffer include/linux/fb.h:654 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0x103a/0x1bf0 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x790/0xaf0 drivers/video/fbdev/core/fbcon.c:1308 con_flush drivers/tty/vt/vt.c:2575 [inline] vc_con_write_normal drivers/tty/vt/vt.c:2803 [inline] do_con_write+0x115b/0xd580 drivers/tty/vt/vt.c:2910 con_write+0x20/0x40 drivers/tty/vt/vt.c:3250 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0xcbf/0x1170 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x593/0x940 drivers/tty/tty_io.c:1046 do_loop_readv_writev fs/read_write.c:737 [inline] do_iter_write+0x441/0x610 fs/read_write.c:1020 vfs_writev fs/read_write.c:1091 [inline] do_writev+0x23f/0x4a0 fs/read_write.c:1134 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e179 Code: 3d b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f3d64282c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 000000000003a200 RCX: 000000000045e179 RDX: 0000000000000001 RSI: 00000000200005c0 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffcaf2f886f R14: 00007f3d642839c0 R15: 000000000118cf4c Allocated by task 14849: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x205/0x300 mm/slab.c:3664 kmalloc include/linux/slab.h:559 [inline] fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2496 con_font_set drivers/tty/vt/vt.c:4663 [inline] con_font_op+0xebc/0x1630 drivers/tty/vt/vt.c:4728 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:506 [inline] vt_ioctl+0xd7f/0x3d70 drivers/tty/vt/vt_ioctl.c:856 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88809edb2c00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 407 bytes to the right of 512-byte region [ffff88809edb2c00, ffff88809edb2e00) The buggy address belongs to the page: page:00000000cc0679b2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9edb2 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00029fc608 ffffea0002560688 ffff8880aa440600 raw: 0000000000000000 ffff88809edb2000 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809edb2e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88809edb2f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809edb2f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88809edb3000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809edb3080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================