WARNING in check_buffer

Status: upstream: reported C repro on 2026/07/27 18:46
Reported-by: syzbot+38fb7fbaf5a7f0540cae@syzkaller.appspotmail.com
First crash: 29d, last: 9d21h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING in check_buffer -1 11 8d12h 29d 0/3 upstream: reported on 2026/07/27 19:37

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4386 at kernel/trace/ring_buffer.c:3485 check_buffer+0x7d7/0x880 kernel/trace/ring_buffer.c:3485
Modules linked in:
CPU: 0 PID: 4386 Comm: syz.2.30 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_buffer+0x7d7/0x880 kernel/trace/ring_buffer.c:3485
Code: 74 24 18 e8 7b 9e 39 08 48 c7 c7 60 ee 33 96 be 04 00 00 00 e8 1a 33 42 00 f0 ff 0d 63 00 b8 14 e9 a9 fe ff ff e8 a9 0e fd ff <0f> 0b e9 fa fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c d0 f8 ff
RSP: 0018:ffffc900032bf7e0 EFLAGS: 00010293
RAX: ffffffff817bee07 RBX: 0000001663f9f3a9 RCX: ffff888074315940
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffff888016c78807 R09: 1ffff11002d8f100
R10: dffffc0000000000 R11: ffffed1002d8f101 R12: ffff888016c78800
R13: dffffc0000000000 R14: ffffc900032bf9a0 R15: dffffc0000000000
FS:  00005555860aa500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000240 CR3: 000000007a49d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __rb_reserve_next+0x4d9/0xd00 kernel/trace/ring_buffer.c:3581
 rb_reserve_next_event kernel/trace/ring_buffer.c:3716 [inline]
 ring_buffer_lock_reserve+0xadd/0xed0 kernel/trace/ring_buffer.c:3775
 __trace_buffer_lock_reserve kernel/trace/trace.c:942 [inline]
 trace_event_buffer_lock_reserve+0xd4/0x6a0 kernel/trace/trace.c:2819
 trace_event_buffer_reserve+0x2a8/0x3d0 kernel/trace/trace_events.c:627
 trace_inject_entry kernel/trace/trace_events_inject.c:24 [inline]
 event_inject_write+0x17e4/0x1c10 kernel/trace/trace_events_inject.c:302
 vfs_write+0x304/0xd70 fs/read_write.c:592
 ksys_write+0x153/0x260 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa667c7e0d9
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:00007ffd86bb19d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa667f05fa0 RCX: 00007fa667c7e0d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007fa667d15024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa667f05fac R14: 00007fa667f05fa0 R15: 00007fa667f05fa0
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/16 16:31 linux-5.15.y aabd761612db 746171ee .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in check_buffer
2026/08/16 12:09 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in check_buffer
2026/08/16 12:09 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in check_buffer
2026/07/27 18:46 linux-5.15.y 674f684f7c61 aae9036b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in check_buffer
* Struck through repros no longer work on HEAD.