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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:22
Read of size 8 at addr ffffc90003bc65f0 by task syz.5.2738/17263

CPU: 0 UID: 0 PID: 17263 Comm: syz.5.2738 Not tainted 6.15.0-syzkaller-12058-g64980441d269 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:408 [inline]
 print_report+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 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:22
 drm_fbdev_shmem_defio_imageblit+0x20/0x130 drivers/gpu/drm/drm_fbdev_shmem.c:37
 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:138 [inline]
 bit_putcs+0x912/0xde0 drivers/video/fbdev/core/bitblit.c:187
 fbcon_putcs+0x380/0x4a0 drivers/video/fbdev/core/fbcon.c:1314
 con_putc+0x141/0x170 drivers/tty/vt/vt.c:302
 complement_pos+0x2d3/0x4e0 drivers/tty/vt/vt.c:757
 highlight_pointer drivers/tty/vt/selection.c:63 [inline]
 clear_selection+0x1b/0x70 drivers/tty/vt/selection.c:85
 hide_cursor+0x1d7/0x220 drivers/tty/vt/vt.c:844
 redraw_screen+0x5d4/0x760 drivers/tty/vt/vt.c:948
 fbcon_blank+0x652/0xd20 drivers/video/fbdev/core/fbcon.c:2257
 do_unblank_screen+0x27e/0x4c0 drivers/tty/vt/vt.c:4561
 unblank_screen drivers/tty/vt/vt.c:4580 [inline]
 tioclinux+0x207/0x5d0 drivers/tty/vt/vt.c:3355
 vt_ioctl+0x2e8f/0x2f50 drivers/tty/vt/vt_ioctl.c:761
 tty_ioctl+0x65a/0x1610 drivers/tty/tty_io.c:2802
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f91ad98e929
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:00007f91ae743038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f91adbb6160 RCX: 00007f91ad98e929
RDX: 0000200000000000 RSI: 000000000000541c RDI: 000000000000000b
RBP: 00007f91ada10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f91adbb6160 R15: 00007fffec352e48
 </TASK>

The buggy address ffffc90003bc65f0 belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90003bc6480: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003bc6500: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90003bc6580: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                                                             ^
 ffffc90003bc6600: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003bc6680: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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