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BUG: KASAN: slab-out-of-bounds in fbcon_get_font+0x1de/0x910 drivers/video/fbdev/core/fbcon.c:2475
Read of size 18 at addr ffff8880925ce60a by task syz-executor.3/4475

CPU: 1 PID: 4475 Comm: syz-executor.3 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+0x1f0/0x31e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:183 [inline]
 check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192
 memcpy+0x25/0x60 mm/kasan/common.c:105
 fbcon_get_font+0x1de/0x910 drivers/video/fbdev/core/fbcon.c:2475
 con_font_get drivers/tty/vt/vt.c:4486 [inline]
 con_font_op+0x664/0x1630 drivers/tty/vt/vt.c:4645
 vt_ioctl+0x179d/0x3ec0 drivers/tty/vt/vt_ioctl.c:265
 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ccd9
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:00007f3e0f454c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000001c300 RCX: 000000000045ccd9
RDX: 0000000020000280 RSI: 0000000000004b60 RDI: 0000000000000003
RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007fff1b22c8cf R14: 00007f3e0f4559c0 R15: 000000000078bf0c

Allocated by task 28525:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x24b/0x330 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 fbcon_set_font+0x2c4/0x970 drivers/video/fbdev/core/fbcon.c:2673
 con_font_set drivers/tty/vt/vt.c:4578 [inline]
 con_font_op+0xebc/0x1630 drivers/tty/vt/vt.c:4643
 vt_ioctl+0x179d/0x3ec0 drivers/tty/vt/vt_ioctl.c:265
 tty_ioctl+0xee4/0x15c0 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:760
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 28080:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 __free_fdtable fs/file.c:34 [inline]
 put_files_struct+0x2c7/0x360 fs/file.c:433
 do_exit+0x5a5/0x1f20 kernel/exit.c:801
 do_group_exit+0x161/0x2d0 kernel/exit.c:903
 __do_sys_exit_group+0x13/0x20 kernel/exit.c:914
 __ia32_sys_exit_group+0x0/0x40 kernel/exit.c:912
 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:912
 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 ffff8880925ce000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1546 bytes inside of
 2048-byte region [ffff8880925ce000, ffff8880925ce800)
The buggy address belongs to the page:
page:ffffea0002497380 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0001293488 ffffea00023f2c08 ffff8880aa400e00
raw: 0000000000000000 ffff8880925ce000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880925ce500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880925ce580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880925ce600: 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff8880925ce680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880925ce700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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