================================================================== BUG: KASAN: slab-out-of-bounds in __fb_pad_aligned_buffer include/linux/fb.h:656 [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+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185 Read of size 1 at addr ffff88808eb781d0 by task syz-executor.4/17002 CPU: 1 PID: 17002 Comm: syz-executor.4 Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 __fb_pad_aligned_buffer include/linux/fb.h:656 [inline] bit_putcs_aligned drivers/video/fbdev/core/bitblit.c:96 [inline] bit_putcs+0xbb6/0xd20 drivers/video/fbdev/core/bitblit.c:185 fbcon_putcs+0x33c/0x3f0 drivers/video/fbdev/core/fbcon.c:1362 con_flush drivers/tty/vt/vt.c:2574 [inline] do_con_write+0xb61/0x1d70 drivers/tty/vt/vt.c:2904 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3249 process_output_block drivers/tty/n_tty.c:595 [inline] n_tty_write+0x3ce/0xf80 drivers/tty/n_tty.c:2333 do_tty_write drivers/tty/tty_io.c:962 [inline] tty_write+0x4d9/0x870 drivers/tty/tty_io.c:1046 vfs_write+0x2b0/0x730 fs/read_write.c:576 ksys_write+0x12d/0x250 fs/read_write.c:631 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ce69 Code: 2d b6 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1d3e765c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000037d40 RCX: 000000000045ce69 RDX: 0000000000000040 RSI: 0000000020000140 RDI: 0000000000000004 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffd561ad4df R14: 00007f1d3e7669c0 R15: 000000000118bf2c Allocated by task 14822: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 __do_kmalloc mm/slab.c:3655 [inline] __kmalloc+0x1a8/0x320 mm/slab.c:3664 kmalloc include/linux/slab.h:559 [inline] fbcon_set_font+0x34f/0x8b0 drivers/video/fbdev/core/fbcon.c:2673 con_font_set drivers/tty/vt/vt.c:4662 [inline] con_font_op+0xd25/0x1110 drivers/tty/vt/vt.c:4727 vt_io_ioctl drivers/tty/vt/vt_ioctl.c:595 [inline] vt_ioctl+0x1be1/0x2c20 drivers/tty/vt/vt_ioctl.c:846 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88808eb78000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 464 bytes inside of 512-byte region [ffff88808eb78000, ffff88808eb78200) The buggy address belongs to the page: page:00000000a458aa9b refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88808eb78c00 pfn:0x8eb78 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00027bf108 ffffea00026cd0c8 ffff8880aa040600 raw: ffff88808eb78c00 ffff88808eb78000 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808eb78080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88808eb78100: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88808eb78180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88808eb78200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88808eb78280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================