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

Status: upstream: reported on 2025/05/28 09:22
Subsystems: fbdev
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+7a63ce155648954e749b@syzkaller.appspotmail.com
First crash: 558d, last: 2h06m
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
ce4f0ca9 repro-c Reproduced: ✅ ❓ KASAN: vmalloc-out-of-bounds Write in fillrect 2026/08/07 14:02 2026/08/07 23:41 2026/08/08 01:45 e4ef95d6
57bd59be assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: vmalloc-out-of-bounds Write in fillrect 2026/05/24 07:12 2026/05/24 07:12 2026/05/24 08:16 c69befb3
▶ ▼ Discussions (17)
Title Replies (including bot) Last reply
[syzbot] Monthly fbdev report (Sep 2026) 0 (1) 2026/09/22 04:33
[syzbot] Monthly fbdev report (Aug 2026) 0 (1) 2026/08/22 04:32
[syzbot] Monthly fbdev report (Jul 2026) 0 (1) 2026/07/21 20:32
[syzbot] Monthly fbdev report (Jun 2026) 0 (1) 2026/06/20 12:32
[syzbot] Monthly fbdev report (May 2026) 0 (1) 2026/05/20 12:32
[syzbot] Monthly fbdev report (Apr 2026) 0 (1) 2026/04/20 07:05
[syzbot] Monthly fbdev report (Mar 2026) 0 (1) 2026/03/19 10:23
[syzbot] Monthly fbdev report (Feb 2026) 0 (1) 2026/02/16 07:33
[PATCH] fbdev: sys_fillrect: Add bounds checking to prevent vmalloc-out-of-bounds 3 (3) 2026/01/24 16:53
[syzbot] Monthly fbdev report (Jan 2026) 0 (1) 2026/01/15 13:09
[syzbot] Monthly fbdev report (Dec 2025) 0 (1) 2025/12/16 01:32
[syzbot] Monthly fbdev report (Nov 2025) 0 (1) 2025/11/14 18:41
[syzbot] Monthly fbdev report (Sep 2025) 0 (1) 2025/09/12 21:33
[syzbot] Monthly fbdev report (Aug 2025) 0 (1) 2025/08/12 12:44
[syzbot] Monthly fbdev report (Jul 2025) 0 (1) 2025/07/14 07:22
[syzbot] Monthly fbdev report (Jun 2025) 0 (1) 2025/06/11 07:46
[syzbot] [fbdev?] KASAN: vmalloc-out-of-bounds Write in fillrect 0 (1) 2025/05/28 09:22
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/08 08:25 19m nogikh@google.com upstream report log

Sample crash report:
==================================================================
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 bitfill drivers/video/fbdev/core/fb_fillrect.h:133 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_fillrect_static drivers/video/fbdev/core/fb_fillrect.h:219 [inline]
BUG: KASAN: vmalloc-out-of-bounds in fb_fillrect drivers/video/fbdev/core/fb_fillrect.h:278 [inline]
BUG: KASAN: vmalloc-out-of-bounds in sys_fillrect+0x174a/0x1910 drivers/video/fbdev/core/sysfillrect.c:24
Write of size 8 at addr ffffc90004ad1000 by task syz.0.345/8379

CPU: 0 UID: 0 PID: 8379 Comm: syz.0.345 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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]
 bitfill drivers/video/fbdev/core/fb_fillrect.h:133 [inline]
 fb_fillrect_static drivers/video/fbdev/core/fb_fillrect.h:219 [inline]
 fb_fillrect drivers/video/fbdev/core/fb_fillrect.h:278 [inline]
 sys_fillrect+0x174a/0x1910 drivers/video/fbdev/core/sysfillrect.c:24
 drm_fbdev_shmem_defio_fillrect+0x22/0x140 drivers/gpu/drm/drm_fbdev_shmem.c:39
 bit_clear+0x17d/0x220 drivers/video/fbdev/core/bitblit.c:72
 __fbcon_clear+0x633/0x760 drivers/video/fbdev/core/fbcon.c:1375
 fbcon_scroll+0x48b/0x650 drivers/video/fbdev/core/fbcon.c:1927
 con_scroll+0x464/0x690 drivers/tty/vt/vt.c:616
 csi_M drivers/tty/vt/vt.c:2191 [inline]
 csi_ECMA.constprop.0+0x1238/0x3b60 drivers/tty/vt/vt.c:2614
 do_con_trol drivers/tty/vt/vt.c:2829 [inline]
 do_con_write+0x3660/0x4a30 drivers/tty/vt/vt.c:3325
 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3661
 process_output_block drivers/tty/n_tty.c:557 [inline]
 n_tty_write+0x431/0x1160 drivers/tty/n_tty.c:2366
 iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
 file_tty_write.isra.0+0x4d2/0x890 drivers/tty/tty_io.c:1081
 tty_write drivers/tty/tty_io.c:1102 [inline]
 redirected_tty_write drivers/tty/tty_io.c:1125 [inline]
 redirected_tty_write+0xd4/0x120 drivers/tty/tty_io.c:1105
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x840 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f50b399de99
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:00007f50b486b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f50b3c25fa0 RCX: 00007f50b399de99
RDX: 000000000000fdef RSI: 0000200000000000 RDI: 0000000000000001
RBP: 00007f50b3a33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f50b3c26038 R14: 00007f50b3c25fa0 R15: 00007fff02aecbc8
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90004ad0f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004ad0f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90004ad1000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90004ad1080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004ad1100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (1139):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/26 03:06 upstream 3dab139d4795 4a865b71 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in fillrect
2026/07/25 23:25 upstream 3dab139d4795 4a865b71 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in fillrect
2026/05/19 09:32 upstream ab5fce87a778 2aa09d96 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in fillrect
2026/03/10 11:39 upstream 1f318b96cc84 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in fillrect
2025/05/20 18:50 upstream a5806cd506af b47f9e02 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/26 06:39 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/25 23:29 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/25 03:47 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/24 12:48 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/23 20:29 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/23 08:14 upstream 3ac032ef6ca8 d566bfda .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 10:31 upstream 4df4d2a577db 4ba27f85 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 06:47 upstream 4df4d2a577db 4ba27f85 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/21 10:30 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 20:17 upstream f47d223627f8 df8746fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 17:51 upstream f47d223627f8 df8746fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/19 20:11 upstream c03c1a14507d 440f8011 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/19 17:39 upstream c03c1a14507d 440f8011 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2025/04/16 00:23 upstream 1a1d569a75f3 a95239b1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/25 19:32 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/25 08:50 upstream 330517c63aa9 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/24 22:36 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/24 18:39 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/24 05:10 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/24 01:52 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/23 11:13 upstream 3ac032ef6ca8 d566bfda .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 23:54 upstream 7be4bc52fd9e 3875c4e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 18:49 upstream 7be4bc52fd9e 3875c4e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 21:37 upstream f47d223627f8 df8746fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 12:08 upstream f47d223627f8 df8746fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 00:47 upstream c03c1a14507d 21286ae2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/08/10 06:33 linux-next cc2b5f627e8c 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/26 04:42 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/25 01:57 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/24 06:27 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/23 15:25 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/23 05:48 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 21:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 16:05 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 07:47 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 05:19 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 01:11 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/22 00:09 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/21 19:12 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/21 08:03 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/21 01:06 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 13:52 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/20 09:09 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/09/19 04:51 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 853b104b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 KASAN: vmalloc-out-of-bounds Write in fillrect
2026/10/25 14:25 upstream 330517c63aa9 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel paging request in fillrect
2026/10/25 11:12 upstream 330517c63aa9 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel paging request in fillrect
2026/10/25 04:37 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: stack-out-of-bounds Write in fillrect
2026/10/23 19:08 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel paging request in fillrect
2026/10/22 20:10 upstream 7be4bc52fd9e 3875c4e4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: stack-out-of-bounds Write in fillrect
2026/10/21 03:58 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: stack-out-of-bounds Write in fillrect
2026/10/26 07:45 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: unable to handle kernel paging request in fillrect
2026/10/25 07:30 upstream 330517c63aa9 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 BUG: unable to handle kernel paging request in fillrect
2026/10/22 17:19 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7a19f0cc94ad 4ba27f85 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: stack-out-of-bounds Write in fillrect
2026/09/02 01:17 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 73ae59e97596 587f6b29 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte BUG: unable to handle kernel paging request in fillrect
* Struck through repros no longer work on HEAD.