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KASAN: vmalloc-out-of-bounds Write in imageblit (6)

Status: upstream: reported C repro on 2025/11/02 21:10
Subsystems: fbdev
[Documentation on labels]
Reported-by: syzbot+5a40432dfe8f86ee657a@syzkaller.appspotmail.com
First crash: 109d, last: 46m
▶ ▼ Discussions (6)
Title Replies (including bot) Last reply
[syzbot] Monthly fbdev report (Feb 2026) 0 (1) 2026/02/16 07:33
[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
[PATCH] fbdev: core: Fix vmalloc-out-of-bounds in fb_imageblit 4 (4) 2025/11/26 06:55
[syzbot] [fbdev?] KASAN: vmalloc-out-of-bounds Write in imageblit (6) 1 (4) 2025/11/19 10:42
[syzbot] Monthly fbdev report (Nov 2025) 0 (1) 2025/11/14 18:41
▶ ▼ 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 21 C 104 1574d 1867d 20/29 fixed on 2021/11/10 00:50
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (5) fbdev 21 C 1075 110d 160d 29/29 fixed on 2025/10/29 21:02
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (4) fbdev 21 C 3869 165d 544d 29/29 fixed on 2025/09/04 16:57
upstream KASAN: vmalloc-out-of-bounds Write in imageblit (3) fbdev 21 2 937d 933d 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 C done 701 1262d 1550d 22/29 fixed on 2023/02/24 13:50
upstream KASAN: vmalloc-out-of-bounds Write in sys_imageblit fbdev 21 C 91 1892d 2260d 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 1889d 2260d 0/29 auto-obsoleted due to no activity on 2022/08/31 01:46
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/11/19 10:18 22m ssranevjti@gmail.com patch upstream OK log

Sample crash report:
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fff34de03f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd0417e5fa0 R14: 00007fd0417e5fa0 R15: 0000000000000003
 </TASK>
==================================================================
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 ffffc90003749fc0 by task syz.0.17/6037

CPU: 0 UID: 0 PID: 6037 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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
 cw_putcs_aligned drivers/video/fbdev/core/fbcon_cw.c:110 [inline]
 cw_putcs+0x917/0xbb0 drivers/video/fbdev/core/fbcon_cw.c:158
 fbcon_putcs+0x387/0x450 drivers/video/fbdev/core/fbcon.c:1320
 do_update_region+0x2e9/0x3f0 drivers/tty/vt/vt.c:628
 redraw_screen+0x63f/0x760 drivers/tty/vt/vt.c:980
 fbcon_modechanged+0x456/0x6b0 drivers/video/fbdev/core/fbcon.c:2710
 fbcon_rotate drivers/video/fbdev/core/fbcon.c:228 [inline]
 rotate_store+0x258/0x2f0 drivers/video/fbdev/core/fbcon.c:3215
 dev_attr_store+0x58/0x80 drivers/base/core.c:2437
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
 kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352
 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/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd04158f6c9
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:00007fff34de0398 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd0417e5fa0 RCX: 00007fd04158f6c9
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fff34de03f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fd0417e5fa0 R14: 00007fd0417e5fa0 R15: 0000000000000003
 </TASK>

The buggy address belongs to a vmalloc virtual mapping
Memory state around the buggy address:
 ffffc90003749e80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90003749f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc90003749f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                                           ^
 ffffc9000374a000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc9000374a080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (1286):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/18 08:00 upstream e7c375b18160 ef766cd7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/16 14:40 upstream 0f2acd3148e0 84656fa6 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/16 05:24 upstream 26a4cfaff82a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/16 04:29 upstream 26a4cfaff82a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/16 03:07 upstream 26a4cfaff82a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/15 22:46 upstream 26a4cfaff82a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/15 17:54 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/15 12:15 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/15 01:54 upstream 3e48a11675c5 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/14 19:28 upstream 3e48a11675c5 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/14 17:43 upstream 770aaedb461a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/14 13:43 upstream 770aaedb461a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/14 12:12 upstream 770aaedb461a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/14 05:29 upstream cee73b1e840c 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/14 00:00 upstream cee73b1e840c 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/13 20:39 upstream cee73b1e840c 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/13 17:16 upstream cee73b1e840c 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/13 11:54 upstream 7449f86bafcd 6a673c50 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/13 11:51 upstream 7449f86bafcd 6a673c50 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/13 09:34 upstream 7449f86bafcd 6a673c50 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/13 01:48 upstream 37a93dd5c49b 504cb1bf .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/12 22:22 upstream 37a93dd5c49b 504cb1bf .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/12 14:19 upstream 37a93dd5c49b 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/12 13:15 upstream 37a93dd5c49b 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/12 05:21 upstream 1e83ccd5921a 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/12 03:06 upstream 1e83ccd5921a 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/11 18:25 upstream 192c0159402e 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/11 18:06 upstream 192c0159402e 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/11 11:22 upstream 192c0159402e 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/11 08:48 upstream dc855b77719f 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/11 04:17 upstream dc855b77719f 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/11 00:53 upstream dc855b77719f 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/10 23:26 upstream dc855b77719f 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/10 21:37 upstream 72c395024dac a076df6f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/10 19:04 upstream 72c395024dac a076df6f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/10 15:57 upstream 72c395024dac a076df6f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/10 09:28 upstream 8a5203c630c6 4ab09a02 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/11/02 16:30 upstream 691d401c7e0e 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/10/29 21:04 upstream e53642b87a4f fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: vmalloc-out-of-bounds Write in imageblit
2025/12/05 11:01 upstream 2061f18ad76e d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/05 18:20 upstream 8fdb05de0e2d 4936e85c .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Write in imageblit
2026/02/16 17:40 upstream 0f2acd3148e0 84656fa6 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/15 09:11 upstream ca4ee40bf13d 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/15 03:27 upstream 3e48a11675c5 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/14 06:33 upstream 770aaedb461a 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/14 02:42 upstream cee73b1e840c 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/13 06:40 upstream 7449f86bafcd 6a673c50 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/11 23:59 upstream 1e83ccd5921a 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/11 19:54 upstream 192c0159402e 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2026/02/10 11:15 upstream 72c395024dac a076df6f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: unable to handle kernel paging request in imageblit
2025/12/11 03:26 upstream 0048fbb4011e d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: vmalloc-out-of-bounds Read in imageblit
* Struck through repros no longer work on HEAD.