================================================================== BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:347 [inline] BUG: KASAN: slab-out-of-bounds in fbcon_get_font+0x262/0x530 drivers/video/fbdev/core/fbcon.c:2424 Read of size 6 at addr ffff88803eeb984e by task syz-executor.2/26334 CPU: 0 PID: 26334 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393 memcpy+0x20/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:347 [inline] fbcon_get_font+0x262/0x530 drivers/video/fbdev/core/fbcon.c:2424 con_font_get drivers/tty/vt/vt.c:4098 [inline] con_font_op+0x1c6/0xf70 drivers/tty/vt/vt.c:4249 vt_ioctl+0x1376/0x1f20 drivers/tty/vt/vt_ioctl.c:980 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45cb29 RSP: 002b:00007f7cc7cfbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e7620 RCX: 000000000045cb29 RDX: 00000000200008c0 RSI: 0000000000004b72 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000037f R14: 00000000004c6226 R15: 00007f7cc7cfc6d4 Allocated by task 22966: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551 __do_kmalloc mm/slab.c:3720 [inline] __kmalloc+0x15a/0x400 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] fbcon_set_font+0x2f8/0x7c0 drivers/video/fbdev/core/fbcon.c:2621 con_font_set drivers/tty/vt/vt.c:4182 [inline] con_font_op+0xb73/0xf70 drivers/tty/vt/vt.c:4247 vt_ioctl+0x736/0x1f20 drivers/tty/vt/vt_ioctl.c:928 tty_ioctl+0x6c9/0x1220 drivers/tty/tty_io.c:2661 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 20990: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 kvfree+0x45/0x50 mm/util.c:416 __free_fdtable+0x2d/0x70 fs/file.c:36 put_files_struct fs/file.c:425 [inline] put_files_struct+0x239/0x2d0 fs/file.c:418 exit_files+0x7e/0xa0 fs/file.c:450 do_exit+0x9d0/0x2ae0 kernel/exit.c:853 do_group_exit+0x100/0x2e0 kernel/exit.c:955 get_signal+0x385/0x1c90 kernel/signal.c:2423 do_signal+0x7c/0x15d0 arch/x86/kernel/signal.c:814 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb The buggy address belongs to the object at ffff88803eeb9340 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1294 bytes inside of 2048-byte region [ffff88803eeb9340, ffff88803eeb9b40) The buggy address belongs to the page: page:ffffea0000fbae00 count:1 mapcount:0 mapping:ffff88803eeb8240 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff88803eeb8240 0000000000000000 0000000100000003 raw: ffffea0001319fa0 ffffea00024ea020 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88803eeb9700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88803eeb9780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88803eeb9800: 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc ^ ffff88803eeb9880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803eeb9900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================