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BUG: KASAN: vmalloc-out-of-bounds in fb_read_offset drivers/video/fbdev/core/sysmem.h:38 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_bitblit drivers/video/fbdev/core/fb_imageblit.h:137 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap1x_imageblit drivers/video/fbdev/core/fb_imageblit.h:275 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:477 [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+0x1deb/0x1e60 drivers/video/fbdev/core/sysimgblt.c:24
Read of size 8 at addr ffffc900051d14a0 by task syz.7.676/8312

CPU: 3 UID: 0 PID: 8312 Comm: syz.7.676 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 lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 fb_read_offset drivers/video/fbdev/core/sysmem.h:38 [inline]
 fb_bitblit drivers/video/fbdev/core/fb_imageblit.h:137 [inline]
 fb_bitmap1x_imageblit drivers/video/fbdev/core/fb_imageblit.h:275 [inline]
 fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:477 [inline]
 fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline]
 sys_imageblit+0x1deb/0x1e60 drivers/video/fbdev/core/sysimgblt.c:24
 drm_fbdev_shmem_defio_imageblit+0x20/0x130 drivers/gpu/drm/drm_fbdev_shmem.c:38
 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:138 [inline]
 bit_putcs+0x912/0xde0 drivers/video/fbdev/core/bitblit.c:187
 fbcon_putcs+0x384/0x450 drivers/video/fbdev/core/fbcon.c:1320
 con_putc+0x144/0x170 drivers/tty/vt/vt.c:302
 complement_pos+0x2d3/0x4e0 drivers/tty/vt/vt.c:766
 highlight_pointer drivers/tty/vt/selection.c:63 [inline]
 clear_selection+0x1b/0x70 drivers/tty/vt/selection.c:85
 vc_do_resize+0xd9b/0x10e0 drivers/tty/vt/vt.c:1196
 vc_resize include/linux/vt_kern.h:49 [inline]
 fbcon_set_disp+0x7ad/0xe50 drivers/video/fbdev/core/fbcon.c:1423
 con2fb_init_display drivers/video/fbdev/core/fbcon.c:821 [inline]
 set_con2fb_map+0x703/0x1080 drivers/video/fbdev/core/fbcon.c:895
 fbcon_set_con2fb_map_ioctl+0x16c/0x220 drivers/video/fbdev/core/fbcon.c:3132
 do_fb_ioctl+0x328/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:138
 fb_ioctl+0xe5/0x150 drivers/video/fbdev/core/fb_chrdev.c:169
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f52ec38eec9
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:00007f52ed227038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f52ec5e5fa0 RCX: 00007f52ec38eec9
RDX: 0000200000000180 RSI: 0000000000004610 RDI: 0000000000000003
RBP: 00007f52ec411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f52ec5e6038 R14: 00007f52ec5e5fa0 R15: 00007ffd08bd3258
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc900051d1380: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc900051d1400: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc900051d1480: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                               ^
 ffffc900051d1500: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc900051d1580: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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