syzbot

 sign-in | mailing list | source | docs
🐞 Open [1513]
≡ Subsystems
🐞 Fixed [6633]
🐞 Invalid [17000]
⬇ Missing Backports [212]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

KASAN: vmalloc-out-of-bounds Write in imageblit (5)

Status: upstream: reported C repro on 2025/09/08 19:19
Subsystems: fbdev
[Documentation on labels]
Reported-by: syzbot+48b0652a95834717f190@syzkaller.appspotmail.com
Fix commit: fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 34d, last: 55m
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[syzbot] [fbdev?] KASAN: vmalloc-out-of-bounds Write in imageblit (5) 0 (7) 2025/10/05 08:53
[PATCH v2] fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds 2 (2) 2025/10/04 00:43
[PATCH] fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds 6 (6) 2025/10/02 10:11
[syzbot] Monthly fbdev report (Sep 2025) 0 (1) 2025/09/12 21:33
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: vmalloc-out-of-bounds Write in imageblit fbdev 23 C 104 1443d 1736d 20/29 fixed on 2021/11/10 00:50
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (4) fbdev 23 C 3869 34d 413d 29/29 fixed on 2025/09/04 16:57
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (3) fbdev 23 2 806d 802d 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 23 C done 701 1132d 1419d 22/29 fixed on 2023/02/24 13:50
upstream KASAN: vmalloc-out-of-bounds Write in sys_imageblit fbdev 23 C 91 1762d 2129d 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 1759d 2129d 0/29 auto-obsoleted due to no activity on 2022/08/31 01:46
upstream KASAN: stack-out-of-bounds Write in sys_imageblit fbdev 23 2 1807d 1906d 0/29 auto-closed as invalid on 2021/02/24 10:13
▶ ▼ Last patch testing requests (5)
Created Duration User Patch Repo Result
2025/10/05 08:53 20m albinbabuvarghese20@gmail.com patch upstream OK log
2025/10/02 07:22 20m albinbabuvarghese20@gmail.com patch upstream OK log
2025/09/27 03:39 19m albinbabuvarghese20@gmail.com patch upstream OK log
2025/09/25 14:09 18m albinbabuvarghese20@gmail.com patch upstream OK log
2025/09/25 13:59 5m albinbabuvarghese20@gmail.com patch upstream error

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 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+0x1a6f/0x1e60 drivers/video/fbdev/core/sysimgblt.c:24
Write of size 8 at addr ffffc90004dd9000 by task syz.0.28/6136

CPU: 1 UID: 0 PID: 6136 Comm: syz.0.28 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 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+0x1a6f/0x1e60 drivers/video/fbdev/core/sysimgblt.c:24
 drm_fbdev_shmem_defio_imageblit+0x20/0x130 drivers/gpu/drm/drm_fbdev_shmem.c:38
 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:138 [inline]
 bit_putcs+0x912/0xde0 drivers/video/fbdev/core/bitblit.c:187
 fbcon_putcs+0x387/0x450 drivers/video/fbdev/core/fbcon.c:1320
 do_update_region+0x2e9/0x3f0 drivers/tty/vt/vt.c:627
 csi_J+0x545/0xad0 drivers/tty/vt/vt.c:1536
 reset_terminal+0x64e/0x770 drivers/tty/vt/vt.c:2204
 handle_esc drivers/tty/vt/vt.c:2387 [inline]
 do_con_trol drivers/tty/vt/vt.c:2594 [inline]
 do_con_write+0x2f9c/0x8280 drivers/tty/vt/vt.c:3174
 con_write+0x23/0xb0 drivers/tty/vt/vt.c:3516
 process_output_block drivers/tty/n_tty.c:561 [inline]
 n_tty_write+0x41b/0x11e0 drivers/tty/n_tty.c:2377
 iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
 file_tty_write.constprop.0+0x503/0x9b0 drivers/tty/tty_io.c:1081
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f566e98eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f566f7ee038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f566ebe6180 RCX: 00007f566e98eec9
RDX: 0000000000000505 RSI: 0000200000001980 RDI: 0000000000000005
RBP: 00007f566ea11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f566ebe6218 R14: 00007f566ebe6180 R15: 00007ffe89095518
 </TASK>

The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90004ad9000 allocated at drm_gem_shmem_vmap_locked+0x561/0x7e0 drivers/gpu/drm/drm_gem_shmem_helper.c:371
Memory state around the buggy address:
 ffffc90004dd8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004dd8f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004dd9000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90004dd9080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90004dd9100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (877):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/05 04:55 upstream cbf33b8e0b36 49379ee0 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/09/15 15:59 upstream f83ec76bf285 e2beed91 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 05:53 upstream 971199ad2a0f 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 13:52 upstream c746c3b51698 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 09:53 upstream c746c3b51698 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 07:52 upstream c746c3b51698 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 06:45 upstream c746c3b51698 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 01:06 upstream c746c3b51698 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 02:22 upstream 6a74422b9710 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 00:42 upstream 6a74422b9710 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 16:00 upstream 6093a688a07d 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 12:09 upstream 6093a688a07d 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 07:52 upstream 6093a688a07d 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/04 13:11 upstream 2ccb4d203fe4 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/04 10:43 upstream 2ccb4d203fe4 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/09/08 17:21 upstream 76eeb9b8de98 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/09/04 19:08 upstream 08b06c30a445 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 19:04 upstream 0d97f2067c16 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 17:26 upstream 0d97f2067c16 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 15:23 upstream 0d97f2067c16 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 14:21 upstream 0d97f2067c16 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 12:27 upstream 0d97f2067c16 7e2882b3 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 04:57 upstream 971199ad2a0f 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 03:50 upstream 971199ad2a0f 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/08 02:11 upstream 971199ad2a0f 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 17:46 upstream 971199ad2a0f 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 15:45 upstream c746c3b51698 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 10:57 upstream c746c3b51698 8ef35d49 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/07 02:50 upstream c746c3b51698 8ef35d49 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 23:46 upstream c746c3b51698 8ef35d49 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 22:25 upstream c746c3b51698 8ef35d49 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 14:19 upstream fd94619c4336 91305dbe .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 06:04 upstream 6a74422b9710 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 05:00 upstream 6a74422b9710 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 00:05 upstream 6a74422b9710 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 22:58 upstream 6a74422b9710 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 20:55 upstream 6a74422b9710 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 17:40 upstream 6093a688a07d 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 14:39 upstream 6093a688a07d 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 11:01 upstream 6093a688a07d 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 08:53 upstream 6093a688a07d 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 06:53 upstream 6093a688a07d 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 01:18 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 00:01 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/04 21:56 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/04 17:04 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/09 03:52 upstream cd5a0afbdf80 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 20:40 upstream fd94619c4336 91305dbe .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/06 15:26 upstream fd94619c4336 91305dbe .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 13:18 upstream 6093a688a07d 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/05 03:14 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/04 18:49 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2025/10/08 08:10 upstream 0d97f2067c16 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Read in imageblit
2025/10/07 21:13 upstream 971199ad2a0f 7e2882b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: stack-out-of-bounds Write in imageblit
2025/10/05 04:35 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel paging request in imageblit
* Struck through repros no longer work on HEAD.