KASAN: global-out-of-bounds Read in bus_uevent_store

Status: upstream: reported C repro on 2026/09/14 16:38
Subsystems: kernel
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+9a321aea9d851b299486@syzkaller.appspotmail.com
First crash: 25d, last: 6d05h
▶ ▼ ✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
6ba007fb assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: global-out-of-bounds Read in bus_uevent_store 2026/09/18 01:04 2026/09/18 01:04 2026/09/18 01:11 8d7d05f1
c88707e4 assessment-security 💥 KASAN: global-out-of-bounds Read in bus_uevent_store 2026/09/15 02:32 2026/09/15 02:32 2026/09/15 02:32 81a27d1a
6ff552a9 repro-c 💥 KASAN: global-out-of-bounds Read in bus_uevent_store 2026/09/14 21:08 2026/09/14 22:46 2026/09/15 00:49 81a27d1a
ae091bd7 assessment-security 💥 KASAN: global-out-of-bounds Read in bus_uevent_store 2026/09/13 23:55 2026/09/13 23:55 2026/09/13 23:55 70a60e12
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] sysfs: prevent writing excessively large files 10 (10) 2026/09/23 12:05
[syzbot] [kernel?] KASAN: global-out-of-bounds Read in bus_uevent_store 3 (7) 2026/09/23 10:47
▶ ▼ Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/09/23 10:26 19m eadavis@sina.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c9 OK job log log
2026/09/15 11:24 41m eadavis@sina.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c9 OK job log log
2026/09/15 11:00 20m eadavis@sina.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c9 OK job log log

Sample crash report:
==================================================================
BUG: KASAN: global-out-of-bounds in kobject_action_type lib/kobject_uevent.c:86 [inline]
BUG: KASAN: global-out-of-bounds in kobject_synth_uevent+0x79d/0x7d0 lib/kobject_uevent.c:200
Read of size 1 at addr ffffffff8d7264cc by task syz.0.17/5928

CPU: 0 UID: 0 PID: 5928 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
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
 kobject_action_type lib/kobject_uevent.c:86 [inline]
 kobject_synth_uevent+0x79d/0x7d0 lib/kobject_uevent.c:200
 bus_uevent_store+0x3d/0x90 drivers/base/bus.c:917
 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f162979e159
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:00007ffe7a1436e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f1629a25fa0 RCX: 00007f162979e159
RDX: 000000000000004d RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f162983506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1629a25fac R14: 00007f1629a25fa0 R15: 00007f1629a25fa0
 </TASK>

The buggy address belongs to the variable:
 uevent_helper_sysctl_table+0xec/0x2a0

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xd726
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea000035c988 ffffea000035c988 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffffff8d726380: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
 ffffffff8d726400: 00 00 00 f9 f9 f9 f9 f9 00 07 f9 f9 f9 f9 f9 f9
>ffffffff8d726480: 04 f9 f9 f9 f9 f9 f9 f9 07 f9 f9 f9 f9 f9 f9 f9
                                              ^
 ffffffff8d726500: 07 f9 f9 f9 f9 f9 f9 f9 05 f9 f9 f9 f9 f9 f9 f9
 ffffffff8d726580: 07 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9
==================================================================

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/01 19:06 upstream d24e8ac715de 6d32eb1f .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: global-out-of-bounds Read in bus_uevent_store
2026/10/01 16:16 upstream 551c722f4080 38f7f0d1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: global-out-of-bounds Read in bus_uevent_store
2026/09/26 20:08 upstream 6812ce4e4379 a3c7249d .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: global-out-of-bounds Read in bus_uevent_store
2026/09/21 07:42 upstream 93f51579e7df 853b104b .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: global-out-of-bounds Read in bus_uevent_store
2026/10/02 05:32 upstream d24e8ac715de 6d32eb1f .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: global-out-of-bounds Read in bus_uevent_store
2026/10/02 02:33 upstream d24e8ac715de 6d32eb1f .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: global-out-of-bounds Read in bus_uevent_store
2026/09/24 15:58 upstream 62f4c998b297 3c3cdf19 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: global-out-of-bounds Read in bus_uevent_store
2026/09/13 23:55 upstream 50d05c7c76c9 70a60e12 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: global-out-of-bounds Read in bus_uevent_store
2026/10/03 12:30 upstream e767a4ea70a3 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: global-out-of-bounds Read in bus_uevent_store
2026/10/03 11:07 upstream e767a4ea70a3 57bbd979 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: global-out-of-bounds Read in bus_uevent_store
2026/10/03 10:36 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci fe98fb51bf62 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: global-out-of-bounds Read in bus_uevent_store
* Struck through repros no longer work on HEAD.