================================================================== BUG: KASAN: slab-out-of-bounds in soft_cursor+0x96b/0xa30 drivers/video/fbdev/core/softcursor.c:61 Read of size 1 at addr ffff8880a82c57a0 by task kworker/0:0/5 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.8.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_power_efficient fb_flashcursor 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/0x436 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 soft_cursor+0x96b/0xa30 drivers/video/fbdev/core/softcursor.c:61 bit_cursor+0x1166/0x17d0 drivers/video/fbdev/core/bitblit.c:386 fb_flashcursor+0x371/0x3e0 drivers/video/fbdev/core/fbcon.c:417 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Allocated by task 10015: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494 __do_kmalloc mm/slab.c:3656 [inline] __kmalloc+0x17a/0x340 mm/slab.c:3665 kmalloc include/linux/slab.h:560 [inline] fbcon_set_font+0x34f/0x8b0 drivers/video/fbdev/core/fbcon.c:2673 con_font_set drivers/tty/vt/vt.c:4578 [inline] con_font_op+0xd25/0x1110 drivers/tty/vt/vt.c:4643 vt_ioctl+0x1180/0x2670 drivers/tty/vt/vt_ioctl.c:928 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff8880a82c5000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1952 bytes inside of 2048-byte region [ffff8880a82c5000, ffff8880a82c5800) The buggy address belongs to the page: page:ffffea0002a0b140 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00029d07c8 ffffea00023c12c8 ffff8880aa000e00 raw: 0000000000000000 ffff8880a82c5000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a82c5680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880a82c5700: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880a82c5780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8880a82c5800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a82c5880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================