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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+0x19fb/0x1d60 drivers/video/fbdev/core/sysimgblt.c:24
Write of size 8 at addr ffffc90024d69c00 by task syz.0.3799/17839

CPU: 0 UID: 0 PID: 17839 Comm: syz.0.3799 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 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+0x19fb/0x1d60 drivers/video/fbdev/core/sysimgblt.c:24
 drm_fbdev_shmem_defio_imageblit+0x20/0x130 drivers/gpu/drm/drm_fbdev_shmem.c:39
 ccw_putcs_aligned drivers/video/fbdev/core/fbcon_ccw.c:126 [inline]
 ccw_putcs+0x92f/0xbb0 drivers/video/fbdev/core/fbcon_ccw.c:176
 fbcon_putcs+0x3b2/0x480 drivers/video/fbdev/core/fbcon.c:1375
 do_update_region+0x2cf/0x3f0 drivers/tty/vt/vt.c:770
 redraw_screen+0x63f/0x760 drivers/tty/vt/vt.c:1122
 vc_do_resize+0xc3d/0xeb0 drivers/tty/vt/vt.c:1425
 vt_resizex drivers/tty/vt/vt_ioctl.c:715 [inline]
 vt_ioctl+0x1e74/0x3170 drivers/tty/vt/vt_ioctl.c:927
 tty_ioctl+0x26a/0x1870 drivers/tty/tty_io.c:2782
 vfs_ioctl fs/ioctl.c:52 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x7b0 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f707dfa8fd9
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:00007f707ee1a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f707e226180 RCX: 00007f707dfa8fd9
RDX: 00002000000006c0 RSI: 000000000000560a RDI: 0000000000000008
RBP: 00007f707e037fed R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f707e226218 R14: 00007f707e226180 R15: 00007ffd3c0d19e8
 </TASK>

The buggy address belongs to a 1024-page vmalloc region starting at 0xffffc90024969000 allocated at kcov_ioctl+0x4d/0x750 kernel/kcov.c:756
Memory state around the buggy address:
 ffffc90024d69b00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90024d69b80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90024d69c00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90024d69c80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90024d69d00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
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