==================================================================
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+0xc28/0x1758 drivers/video/fbdev/core/sysimgblt.c:24
Write of size 8 at addr ffff800094099fc0 by task syz.3.319/6184

CPU: 1 UID: 0 PID: 6184 Comm: syz.3.319 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __asan_report_store8_noabort+0x20/0x2c mm/kasan/report_generic.c:386
 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+0xc28/0x1758 drivers/video/fbdev/core/sysimgblt.c:24
 drm_fbdev_shmem_defio_imageblit+0x38/0x144 drivers/gpu/drm/drm_fbdev_shmem.c:39
 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:111 [inline]
 cw_putcs+0x69c/0x8bc drivers/video/fbdev/core/fbcon_cw.c:159
 fbcon_putcs+0x258/0x390 drivers/video/fbdev/core/fbcon.c:1375
 do_update_region+0x31c/0x3c8 drivers/tty/vt/vt.c:770
 redraw_screen+0x388/0x51c drivers/tty/vt/vt.c:1122
 vc_do_resize+0x884/0xbbc drivers/tty/vt/vt.c:1425
 __vc_resize+0x60/0x74 drivers/tty/vt/vt.c:1447
 vt_resizex+0x318/0x4b0 drivers/tty/vt/vt_ioctl.c:715
 vt_ioctl+0x734/0x1d4c drivers/tty/vt/vt_ioctl.c:927
 tty_ioctl+0x82c/0xd04 drivers/tty/tty_io.c:2782
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606

The buggy address belongs to a 0-page vmalloc region starting at 0xffff800093d99000 allocated at drm_gem_shmem_vmap_locked+0x45c/0x690 drivers/gpu/drm/drm_gem_shmem_helper.c:415
Memory state around the buggy address:
 ffff800094099e80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffff800094099f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffff800094099f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                                           ^
 ffff80009409a000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffff80009409a080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================
Unable to handle kernel paging request at virtual address ffff800094099fc0
KASAN: probably user-memory-access in range [0x00000004a04cfe00-0x00000004a04cfe07]
Mem abort info:
  ESR = 0x0000000096000047
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x07: level 3 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000047, ISS2 = 0x00000000
  CM = 0, WnR = 1, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000002193b5000
[ffff800094099fc0] pgd=0000000000000000, p4d=100000021f6f0003, pud=100000021f6f1003, pmd=100000010767c403, pte=0000000000000000
Internal error: Oops: 0000000096000047 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 6184 Comm: syz.3.319 Tainted: G    B        L      syzkaller #0 PREEMPT 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline]
pc : fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline]
pc : fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline]
pc : fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline]
pc : sys_imageblit+0xc30/0x1758 drivers/video/fbdev/core/sysimgblt.c:24
lr : fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline]
lr : fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline]
lr : fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline]
lr : fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline]
lr : sys_imageblit+0xc28/0x1758 drivers/video/fbdev/core/sysimgblt.c:24
sp : ffff800096f773a0
x29: ffff800096f77420 x28: dfff800000000000 x27: ffff800094098ff8
x26: ffff800094099fc0 x25: ffff0000c24193e0 x24: 0000000000000004
x23: 0000000000000000 x22: ffff800094099fc0 x21: 0000000000000000
x20: ffff0000c24193e1 x19: ffff800096f773f8 x18: 00000000ffffffff
x17: 3d3d3d3d3d3d3d3d x16: 3d3d3d3d3d3d3d3d x15: 3d3d3d3d3d3d3d3d
x14: 0000000000000ff2 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000080000 x9 : 0000000000000000
x8 : ffff0000d90a3b00 x7 : 0000000000000000 x6 : ffff8000804a0a1c
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff80008030c7b4
x2 : 0000000000000000 x1 : ffff0000d90a3b00 x0 : ffff800094099fc0
Call trace:
 fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:365 [inline] (P)
 fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline] (P)
 fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline] (P)
 sys_imageblit+0xc30/0x1758 drivers/video/fbdev/core/sysimgblt.c:24 (P)
 drm_fbdev_shmem_defio_imageblit+0x38/0x144 drivers/gpu/drm/drm_fbdev_shmem.c:39
 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:111 [inline]
 cw_putcs+0x69c/0x8bc drivers/video/fbdev/core/fbcon_cw.c:159
 fbcon_putcs+0x258/0x390 drivers/video/fbdev/core/fbcon.c:1375
 do_update_region+0x31c/0x3c8 drivers/tty/vt/vt.c:770
 redraw_screen+0x388/0x51c drivers/tty/vt/vt.c:1122
 vc_do_resize+0x884/0xbbc drivers/tty/vt/vt.c:1425
 __vc_resize+0x60/0x74 drivers/tty/vt/vt.c:1447
 vt_resizex+0x318/0x4b0 drivers/tty/vt/vt_ioctl.c:715
 vt_ioctl+0x734/0x1d4c drivers/tty/vt/vt_ioctl.c:927
 tty_ioctl+0x82c/0xd04 drivers/tty/tty_io.c:2782
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606
Code: aa1a03e0 97b6a6c5 aa1a03e0 d34416e9 (f8008415) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa1a03e0 	mov	x0, x26
   4:	97b6a6c5 	bl	0xfffffffffeda9b18
   8:	aa1a03e0 	mov	x0, x26
   c:	d34416e9 	ubfx	x9, x23, #4, #2
* 10:	f8008415 	str	x21, [x0], #8 <-- trapping instruction