[v6.1] panic: runtime error: floating point error

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 58485ff1a74f Linux 6.1.141
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16214e82580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c186557a18643a0b
dashboard link: https://syzkaller.appspot.com/bug?extid=4240452188a65905ca5d
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=120a710c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/50f937e6976c/disk-58485ff1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/32fbd75d9fae/vmlinux-58485ff1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/56b5a2c82bda/bzImage-58485ff1.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+424045...@syzkaller.appspotmail.com

2025/06/14 16:02:17 executed programs: 2
panic: runtime error: floating point error
[signal SIGFPE: floating-point exception code=0x80 addr=0x0 pc=0xf11fe6]

goroutine 15 [running]:
encoding/binary.AppendUvarint(...)
/syzkaller/gopath/pkg/mod/golang.org/tool...@v0.0.1-go1.23.7.linux-amd64/src/encoding/binary/varint.go:46
encoding/binary.AppendVarint(...)
/syzkaller/gopath/pkg/mod/golang.org/tool...@v0.0.1-go1.23.7.linux-amd64/src/encoding/binary/varint.go:96
github.com/google/syzkaller/prog.(*execContext).write(...)
/syzkaller/gopath/src/github.com/google/syzkaller/prog/encodingexec.go:254
github.com/google/syzkaller/prog.(*Prog).SerializeForExec(0xc000a72640)
/syzkaller/gopath/src/github.com/google/syzkaller/prog/encodingexec.go:75 +0x146
github.com/google/syzkaller/pkg/rpcserver.(*Runner).sendRequest(0xc002589080, 0xc002059500)
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/rpcserver/runner.go:297 +0x22e
github.com/google/syzkaller/pkg/rpcserver.(*Runner).ConnectionLoop(0xc002589080)
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/rpcserver/runner.go:182 +0x545
github.com/google/syzkaller/pkg/rpcserver.(*server).connectionLoop(0xc002f10900, {0x21f1060?, 0xc0004b4410?}, 0xc002589080)
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/rpcserver/rpcserver.go:437 +0x196
github.com/google/syzkaller/pkg/rpcserver.(*server).handleRunnerConn(0xc002f10900, {0x21f1060, 0xc0004b4410}, 0xc002589080, 0xc0004b4460)
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/rpcserver/rpcserver.go:360 +0x56a
github.com/google/syzkaller/pkg/rpcserver.(*server).handleConn(0xc002f10900, {0x21f1060, 0xc0004b4410}, 0xc0004b4460)
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/rpcserver/rpcserver.go:322 +0x2ab
github.com/google/syzkaller/pkg/rpcserver.(*server).Serve.func1.1({0x21f1060?, 0xc0004b4410?}, 0x10?)
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/rpcserver/rpcserver.go:242 +0x31
github.com/google/syzkaller/pkg/flatrpc.(*Serv).Serve.func2()
/syzkaller/gopath/src/github.com/google/syzkaller/pkg/flatrpc/conn.go:78 +0x198
golang.org/x/sync/errgroup.(*Group).Go.func1()
/syzkaller/gopath/pkg/mod/golang.org/x/sy...@v0.13.0/errgroup/errgroup.go:79 +0x50
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 10
/syzkaller/gopath/pkg/mod/golang.org/x/sy...@v0.13.0/errgroup/errgroup.go:76 +0x96


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup