KASAN: vmalloc-out-of-bounds Write in imageblit

Status: upstream: reported on 2026/08/05 13:55
Reported-by: syzbot+802bf88adfebfa7c354f@syzkaller.appspotmail.com
First crash: 47d, last: 4h01m
▶ ▼ Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: vmalloc-out-of-bounds Write in imageblit fbdev 21 syz, C 104 1791d 2084d 20/29 fixed on 2021/11/10 00:50
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (6) prio:high fbdev 21 syz, C 9734 7m 323d 0/29 upstream: reported C repro on 2025/11/02 21:10
linux-5.15 KASAN: vmalloc-out-of-bounds Write in imageblit 21 46 3h54m 46d 0/3 upstream: reported on 2026/08/06 13:30
linux-6.1 KASAN: vmalloc-out-of-bounds Write in imageblit origin:lts-only 21 syz, C 133 4h02m 45d 0/3 upstream: reported C repro on 2026/08/07 05:50
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (5) fbdev 21 syz, C 1075 327d 378d 29/29 fixed on 2025/10/29 21:02
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (4) fbdev 21 syz, C 3869 382d 761d 29/29 fixed on 2025/09/04 16:57
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (3) fbdev 21 2 1154d 1150d 0/29 auto-obsoleted due to no activity on 2023/10/23 10:50
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (2) fbdev 21 syz, C done 701 1479d 1767d 22/29 fixed on 2023/02/24 13:50
upstream KASAN: vmalloc-out-of-bounds Write in sys_imageblit fbdev 21 syz, C 91 2109d 2477d 0/29 auto-obsoleted due to no activity on 2022/12/09 01:09
upstream BUG: unable to handle kernel paging request in sys_imageblit fbdev 8 syz 16 2107d 2477d 0/29 auto-obsoleted due to no activity on 2022/08/31 01:46

Sample crash report:
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline]
BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x1bac/0x25d0 drivers/video/fbdev/core/sysimgblt.c:323
Write of size 4 at addr ffffc90003f09000 by task syz.5.425/7449

CPU: 0 PID: 7449 Comm: syz.5.425 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:257 [inline]
 sys_imageblit+0x1bac/0x25d0 drivers/video/fbdev/core/sysimgblt.c:323
 drm_fbdev_generic_defio_imageblit+0x2c/0x110 drivers/gpu/drm/drm_fbdev_generic.c:37
 soft_cursor+0xa01/0xc30 drivers/video/fbdev/core/softcursor.c:74
 bit_cursor+0x16dd/0x1f60 drivers/video/fbdev/core/bitblit.c:409
 hide_cursor+0x7f/0x320 drivers/tty/vt/vt.c:855
 do_con_write+0x1e1/0x70a0 drivers/tty/vt/vt.c:2881
 con_write+0x24/0x40 drivers/tty/vt/vt.c:3245
 process_output_block drivers/tty/n_tty.c:580 [inline]
 n_tty_write+0xd3d/0x11e0 drivers/tty/n_tty.c:2395
 iterate_tty_write drivers/tty/tty_io.c:1017 [inline]
 file_tty_write+0x529/0x960 drivers/tty/tty_io.c:1088
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fafa7f9e159
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:00007fafa8ed3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fafa8225fa0 RCX: 00007fafa7f9e159
RDX: 0000000000001006 RSI: 0000200000000e00 RDI: 0000000000000005
RBP: 00007fafa803506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fafa8226038 R14: 00007fafa8225fa0 R15: 00007ffc348ce0e8
 </TASK>

The buggy address belongs to a 768-page vmalloc region starting at 0xffffc90003c09000 allocated at drm_fbdev_generic_helper_fb_probe+0x247/0x520 drivers/gpu/drm/drm_fbdev_generic.c:97
Memory state around the buggy address:
 ffffc90003f08f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003f08f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90003f09000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90003f09080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003f09100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (42):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/21 17:36 linux-6.6.y 79643295eba1 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/20 02:14 linux-6.6.y 79643295eba1 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/15 15:41 linux-6.6.y 79643295eba1 2daa4bb5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/15 15:40 linux-6.6.y 79643295eba1 2daa4bb5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/13 14:11 linux-6.6.y 8b73de7da85f 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/09 18:40 linux-6.6.y 8b73de7da85f 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/07 20:09 linux-6.6.y 8b73de7da85f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/05 07:18 linux-6.6.y 8b73de7da85f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/05 07:17 linux-6.6.y 8b73de7da85f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/04 23:51 linux-6.6.y 8b73de7da85f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/04 23:51 linux-6.6.y 8b73de7da85f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/04 04:51 linux-6.6.y 8b73de7da85f 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/02 07:02 linux-6.6.y a4a971135a2f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/02 07:02 linux-6.6.y a4a971135a2f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/02 07:02 linux-6.6.y a4a971135a2f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/02 07:02 linux-6.6.y a4a971135a2f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/01 23:40 linux-6.6.y a4a971135a2f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/01 23:37 linux-6.6.y a4a971135a2f 587f6b29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/01 10:25 linux-6.6.y a4a971135a2f 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/31 05:02 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/31 05:01 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/30 10:03 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/29 00:33 linux-6.6.y a4a971135a2f 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/27 12:19 linux-6.6.y dc6160265ffc 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/27 12:18 linux-6.6.y dc6160265ffc 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/27 12:18 linux-6.6.y dc6160265ffc 69a01293 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/26 10:20 linux-6.6.y dc6160265ffc 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/25 04:39 linux-6.6.y dc6160265ffc 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/19 19:27 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/14 14:48 linux-6.6.y d27334b2888c 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/12 19:40 linux-6.6.y d27334b2888c 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/12 03:42 linux-6.6.y d27334b2888c f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/12 03:42 linux-6.6.y d27334b2888c f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/10 09:53 linux-6.6.y d27334b2888c 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/10 05:45 linux-6.6.y d27334b2888c 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/07 22:13 linux-6.6.y 6436c12a2ced e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/07 05:33 linux-6.6.y 80dfb0405055 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/05 13:55 linux-6.6.y aa0e49877a2e 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/09/14 15:50 linux-6.6.y 79643295eba1 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in imageblit
2026/09/14 15:50 linux-6.6.y 79643295eba1 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in imageblit
2026/08/19 05:18 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in imageblit
2026/08/19 05:07 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in imageblit
* Struck through repros no longer work on HEAD.