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BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0xfe2/0x1e50
Write of size 8 at addr ffffc90004bb9000 by task syz.1.378/7242

CPU: 1 UID: 0 PID: 7242 Comm: syz.1.378 Not tainted syzkaller #0 PREEMPT(full) 
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+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 sys_imageblit+0xfe2/0x1e50
 drm_fbdev_shmem_defio_imageblit+0x2c/0x110
 bit_putcs+0x1763/0x1a50
 fbcon_putcs+0x3a6/0x580
 do_update_region+0x38b/0x440
 invert_screen+0x860/0x9f0
 clear_selection+0x59/0x80
 vc_do_resize+0x471/0x1770
 fbcon_set_disp+0x9ec/0xf90
 set_con2fb_map+0xb43/0x13c0
 fbcon_set_con2fb_map_ioctl+0x18a/0x1f0
 do_fb_ioctl+0x3df/0x750
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd1d558ec29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd1d64f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd1d57d5fa0 RCX: 00007fd1d558ec29
RDX: 000020000000a240 RSI: 0000000000004610 RDI: 0000000000000003
RBP: 00007fd1d5611e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd1d57d6038 R14: 00007fd1d57d5fa0 R15: 00007ffc18e6c2c8
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90004bb8f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004bb8f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90004bb9000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90004bb9080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004bb9100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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