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

Status: upstream: reported on 2026/08/07 05:50
Reported-by: syzbot+5de3002e518884f6bfb9@syzkaller.appspotmail.com
First crash: 9d13h, last: 6h20m
▶ ▼ 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 1755d 2048d 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 7534 15m 286d 0/29 upstream: reported C repro on 2025/11/02 21:10
linux-5.15 KASAN: vmalloc-out-of-bounds Write in imageblit 21 11 13h39m 10d 0/3 upstream: reported on 2026/08/06 13:30
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (5) fbdev 21 syz, C 1075 291d 341d 29/29 fixed on 2025/10/29 21:02
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (4) fbdev 21 syz, C 3869 346d 725d 29/29 fixed on 2025/09/04 16:57
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (3) fbdev 21 2 1118d 1114d 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 1443d 1731d 22/29 fixed on 2023/02/24 13:50
linux-6.6 KASAN: vmalloc-out-of-bounds Write in imageblit 21 9 2d04h 11d 0/2 upstream: reported on 2026/08/05 13:55
upstream KASAN: vmalloc-out-of-bounds Write in sys_imageblit fbdev 21 syz, C 91 2073d 2441d 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 2070d 2441d 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:276 [inline]
BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x2110/0x25d0 drivers/video/fbdev/core/sysimgblt.c:323
Write of size 4 at addr ffffc90004549fe8 by task syz.7.5477/24939

CPU: 1 PID: 24939 Comm: syz.7.5477 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 fast_imageblit drivers/video/fbdev/core/sysimgblt.c:276 [inline]
 sys_imageblit+0x2110/0x25d0 drivers/video/fbdev/core/sysimgblt.c:323
 drm_fb_helper_sys_imageblit+0x2e/0x510 drivers/gpu/drm/drm_fb_helper.c:864
 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:110 [inline]
 cw_putcs+0x15ef/0x18a0 drivers/video/fbdev/core/fbcon_cw.c:158
 fbcon_putcs+0x358/0x510 drivers/video/fbdev/core/fbcon.c:1300
 do_update_region+0x4e5/0x640 drivers/tty/vt/vt.c:676
 redraw_screen+0xa2c/0x1000 drivers/tty/vt/vt.c:1035
 vc_do_resize+0x122c/0x17b0 drivers/tty/vt/vt.c:1342
 fbcon_do_set_font+0xb5c/0x1ae0 drivers/video/fbdev/core/fbcon.c:2446
 con_font_set drivers/tty/vt/vt.c:4678 [inline]
 con_font_op+0xac1/0xdb0 drivers/tty/vt/vt.c:4724
 vt_k_ioctl drivers/tty/vt/vt_ioctl.c:474 [inline]
 vt_ioctl+0x1635/0x1cc0 drivers/tty/vt/vt_ioctl.c:752
 tty_ioctl+0x7e6/0xba0 drivers/tty/tty_io.c:2776
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ffa4359e0d9
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:00007ffa444e2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffa43825fa0 RCX: 00007ffa4359e0d9
RDX: 0000200000000180 RSI: 0000000000004b72 RDI: 0000000000000003
RBP: 00007ffa43635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffa43826038 R14: 00007ffa43825fa0 R15: 00007ffec9668718
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90004549e80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004549f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90004549f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                                                          ^
 ffffc9000454a000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc9000454a080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (26):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/14 02:36 linux-6.1.y e4f7d8be268e b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/13 15:16 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/13 15:16 linux-6.1.y e4f7d8be268e 359b2492 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/11 07:18 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/10 22:46 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/10 22:45 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/07 05:49 linux-6.1.y 03f3a99e8e93 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/15 21:17 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/15 01:27 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/14 21:57 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/14 08:58 linux-6.1.y e4f7d8be268e b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/11 02:49 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/11 02:47 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/11 02:47 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/11 02:47 linux-6.1.y e4f7d8be268e 508909ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/08 19:56 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/08/16 12:41 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/16 04:25 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/15 22:34 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/15 04:51 linux-6.1.y e4f7d8be268e 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/14 12:44 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/14 12:44 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/14 12:44 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/11 20:15 linux-6.1.y e4f7d8be268e 71790083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/10 16:03 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
2026/08/10 12:25 linux-6.1.y e4f7d8be268e 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in imageblit
* Struck through repros no longer work on HEAD.