loop0: detected capacity change from 0 to 32768
BTRFS: device fsid a6a605fc-d5f1-4e66-8595-3726e2b761d6 devid 1 transid 8 /dev/loop0 (7:0) scanned by syz.0.0 (5317)
BTRFS info (device loop0): first mount of filesystem a6a605fc-d5f1-4e66-8595-3726e2b761d6
BTRFS info (device loop0): using blake2b (blake2b-256-generic) checksum algorithm
BTRFS error (device loop0): failed to load root extent
BTRFS error (device loop0): open_ctree failed: -5
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline]
BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0xfe2/0x1e50 drivers/video/fbdev/core/sysimgblt.c:24
Write of size 8 at addr ffffc90001de1000 by task syz.0.0/5317

CPU: 0 UID: 0 PID: 5317 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline]
 fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline]
 fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline]
 fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline]
 sys_imageblit+0xfe2/0x1e50 drivers/video/fbdev/core/sysimgblt.c:24
 drm_fbdev_shmem_defio_imageblit+0x2c/0x110 drivers/gpu/drm/drm_fbdev_shmem.c:38
 bit_putcs+0x1760/0x1a50 drivers/video/fbdev/core/bitblit.c:-1
 fbcon_putcs+0x3a6/0x580 drivers/video/fbdev/core/fbcon.c:1320
 do_update_region+0x388/0x440 drivers/tty/vt/vt.c:628
 invert_screen+0x860/0x9f0 drivers/tty/vt/vt.c:749
 highlight drivers/tty/vt/selection.c:57 [inline]
 clear_selection+0x59/0x80 drivers/tty/vt/selection.c:87
 vc_do_resize+0x471/0x1770 drivers/tty/vt/vt.c:1196
 vc_resize include/linux/vt_kern.h:49 [inline]
 fbcon_set_disp+0x9ec/0xf90 drivers/video/fbdev/core/fbcon.c:1423
 con2fb_init_display drivers/video/fbdev/core/fbcon.c:821 [inline]
 set_con2fb_map+0xb43/0x13c0 drivers/video/fbdev/core/fbcon.c:895
 fbcon_set_con2fb_map_ioctl+0x18a/0x1f0 drivers/video/fbdev/core/fbcon.c:3132
 do_fb_ioctl+0x3df/0x750 drivers/video/fbdev/core/fb_chrdev.c:138
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9a7e78eec9
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:00007f9a7f6ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9a7e9e5fa0 RCX: 00007f9a7e78eec9
RDX: 00002000000000c0 RSI: 0000000000004610 RDI: 0000000000000008
RBP: 00007f9a7e811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9a7e9e6038 R14: 00007f9a7e9e5fa0 R15: 00007ffd30dc02f8
 </TASK>

The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90001ae1000 allocated at drm_gem_shmem_vmap_locked+0x556/0x790 drivers/gpu/drm/drm_gem_shmem_helper.c:371
Memory state around the buggy address:
 ffffc90001de0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90001de0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90001de1000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90001de1080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90001de1100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================