[v5.15] WARNING in check_buffer

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10cc9632580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=38fb7fbaf5a7f0540cae
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+38fb7f...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 4646 at kernel/trace/ring_buffer.c:3485 check_buffer+0x7d7/0x880 kernel/trace/ring_buffer.c:3485
Modules linked in:
CPU: 0 PID: 4646 Comm: syz.2.130 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:check_buffer+0x7d7/0x880 kernel/trace/ring_buffer.c:3485
Code: 74 24 18 e8 ab 99 39 08 48 c7 c7 60 ee 33 96 be 04 00 00 00 e8 1a 33 42 00 f0 ff 0d 93 fb b7 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:ffffc9000322f5b0 EFLAGS: 00010287
RAX: ffffffff817bf2d7 RBX: 000000102703e28c RCX: 0000000000080000
RDX: ffffc9000d0e1000 RSI: 0000000000000e3b RDI: 0000000000000e3c
RBP: 0000000000000002 R08: ffff888016c78807 R09: 1ffff11002d8f100
R10: dffffc0000000000 R11: ffffed1002d8f101 R12: ffff888016c78800
R13: dffffc0000000000 R14: ffffc9000322f770 R15: dffffc0000000000
FS: 00007f5d072c56c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9321ea6ff8 CR3: 00000000734cd000 CR4: 00000000003526f0
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_write+0xb5e/0x1510 kernel/trace/ring_buffer.c:3925
__buffer_unlock_commit kernel/trace/trace.c:987 [inline]
trace_buffer_unlock_commit_regs+0x8d/0x5c0 kernel/trace/trace.c:2947
trace_event_buffer_commit+0x21f/0x780 kernel/trace/trace.c:2922
trace_event_raw_event_task_rename+0x210/0x350 include/trace/events/task.h:34
trace_task_rename include/trace/events/task.h:34 [inline]
__set_task_comm+0x1ae/0x210 fs/exec.c:1231
set_task_comm include/linux/sched.h:1941 [inline]
__kthread_create_on_node+0x35c/0x460 kernel/kthread.c:423
kthread_create_on_node+0xe8/0x140 kernel/kthread.c:468
kvm_vm_create_worker_thread+0x165/0x270 virt/kvm/kvm_main.c:5837
kvm_mmu_post_init_vm+0x2e/0x80 arch/x86/kvm/mmu/mmu.c:6319
kvm_create_vm virt/kvm/kvm_main.c:1160 [inline]
kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:4754 [inline]
kvm_dev_ioctl+0x13d5/0x20a0 virt/kvm/kvm_main.c:4809
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
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: 0033:0x7f5d0906ce99
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:00007f5d072c5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5d092f4fa0 RCX: 00007f5d0906ce99
RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000003
RBP: 00007f5d09102eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5d092f5038 R14: 00007f5d092f4fa0 R15: 00007ffe71431dd8
</TASK>


---
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[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dc5c83b7f5f8 Linux 6.1.178
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=15a3c49e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=31dfefc4a14efea3
dashboard link: https://syzkaller.appspot.com/bug?extid=c202c0341faf948688f8

compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/a9aa438e39c2/disk-dc5c83b7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a7b5afd2e170/vmlinux-dc5c83b7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c7673d370fb/bzImage-dc5c83b7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+c202c0...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5893 at kernel/trace/ring_buffer.c:3526 check_buffer+0x88a/0x930 kernel/trace/ring_buffer.c:3526
Modules linked in:
CPU: 0 PID: 5893 Comm: syz.3.436 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026

RIP: 0010:check_buffer+0x88a/0x930 kernel/trace/ring_buffer.c:3526
Code: 4c 89 ee e8 98 b9 9f 08 48 c7 c7 20 04 c6 96 be 04 00 00 00 e8 87 1d 4e 00 f0 ff 0d 50 bf 40 15 e9 91 fe ff ff e8 16 ef fc ff <0f> 0b e9 e2 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 20 f8 ff
RSP: 0018:ffffc900046079d0 EFLAGS: 00010283
RAX: ffffffff818544da RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc90017da4000 RSI: 0000000000000042 RDI: 0000000000000043
RBP: ffffc90004607b88 R08: ffff888017478807 R09: 1ffff11002e8f100
R10: dffffc0000000000 R11: ffffed1002e8f101 R12: 0000002663e02372
R13: 00000000000000bc R14: ffff888017478800 R15: dffffc0000000000
FS: 00007fa0af9046c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000110c29221e CR3: 0000000020303000 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:3622
rb_reserve_next_event kernel/trace/ring_buffer.c:3757 [inline]
ring_buffer_lock_reserve+0xafa/0xf10 kernel/trace/ring_buffer.c:3816
__trace_buffer_lock_reserve kernel/trace/trace.c:956 [inline]
tracing_mark_write+0x1f6/0x840 kernel/trace/trace.c:7245
vfs_write+0x2dc/0x9a0 fs/read_write.c:582
ksys_write+0x14d/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa0ae99de99

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:00007fa0af904028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa0aec25fa0 RCX: 00007fa0ae99de99
RDX: 000000000000005b RSI: 0000200000000240 RDI: 0000000000000003
RBP: 00007fa0aea33eaf R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fa0aec26038 R14: 00007fa0aec25fa0 R15: 00007ffd5b579b78

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: aabd761612db Linux 5.15.215
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=157196c6580000

kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=38fb7fbaf5a7f0540cae
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=174c7a79580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=104a6a25580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f636f56d3662/disk-aabd7616.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f1a46620f40c/vmlinux-aabd7616.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9b78bb48b022/bzImage-aabd7616.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+38fb7f...@syzkaller.appspotmail.com

------------[ 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>


---
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