CVE-2026-89603 entry: Fix seccomp bypass after ptrace with TSYNC

In the Linux kernel, the following vulnerability has been resolved: entry: Fix seccomp bypass after ptrace with TSYNC Sashiko review pointed out the following issue. If a thread is stopped in syscalltraceenter for ptrace, another thread can install a seccomp filter with SECCOMPFILTERFLAGTSYNC e.g...