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BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0xff5/0x1e40
Write of size 8 at addr ffffc90004b61fc0 by task syz.2.2261/11433

CPU: 1 UID: 0 PID: 11433 Comm: syz.2.2261 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_address_description+0x55/0x1e0
 print_report+0x58/0x70
 kasan_report+0x117/0x150
 sys_imageblit+0xff5/0x1e40
 drm_fbdev_shmem_defio_imageblit+0x2c/0x110
 cw_putcs+0x1626/0x18e0
 fbcon_putcs+0x3c5/0x5a0
 do_update_region+0x389/0x440
 redraw_screen+0xa3d/0x1020
 vc_do_resize+0xffc/0x1550
 vt_resizex+0x3d7/0x570
 vt_ioctl+0x135c/0x20d0
 tty_ioctl+0x920/0xdd0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f348919e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f348a00c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3489426180 RCX: 00007f348919e019
RDX: 00002000000006c0 RSI: 000000000000560a RDI: 0000000000000008
RBP: 00007f348923500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3489426218 R14: 00007f3489426180 R15: 00007ffcb1cff1d8
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90004b61e80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004b61f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90004b61f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                                           ^
 ffffc90004b62000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004b62080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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