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sensor/ptrace fix: don't re-inject kernel-generated SIGSTOPs into tracees - #200
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…cees The collect loop re-injected every non-SIGTRAP stop signal on resume, including the SIGSTOP the kernel queues on a freshly auto-attached thread (PTRACE_O_TRACECLONE). Delivering it puts the whole thread group into a group-stop. Traced threads get resumed by the next PTRACE_SYSCALL, but untraced kernel threads in the group (io_uring iou-sqp-*/iou-wrk-* used by Node.js/libuv) stay stopped forever, so the app never starts listening and the HTTP probe fails or hangs. Use PTRACE_GETSIGINFO to tell a real stop signal (sent via kill) from the auto-attach SIGSTOP and group-stop notifications, and only inject the real one. Also resume the stopped tracee after a syscall handler error instead of the previous pid, and finish collection on wait4 ECHILD instead of spinning. Fixes the hang with ghcr.io/iximiuz/labs/mintoolkit/nuxt-web-app:v1.0.0. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Code Review SummaryStatus: No Issues Found | Recommendation: Merge Files Reviewed (1 files)
Reviewed by free · Input: 66.5K · Output: 23.7K · Cached: 337.3K |
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The collect loop re-injected every non-SIGTRAP stop signal on resume, including the SIGSTOP the kernel queues on a freshly auto-attached thread (PTRACE_O_TRACECLONE). Delivering it puts the whole thread group into a group-stop. Traced threads get resumed by the next PTRACE_SYSCALL, but untraced kernel threads in the group (io_uring iou-sqp-/iou-wrk- used by Node.js/libuv) stay stopped forever, so the app never starts listening, and the HTTP probe fails or hangs.
Use PTRACE_GETSIGINFO to tell a real stop signal (sent via kill) from the auto-attach SIGSTOP and group-stop notifications, and only inject the real one. Also resume the stopped tracee after a syscall handler error instead of the previous pid, and finish collection on wait4 ECHILD instead of spinning.
Fixes the hang with ghcr.io/iximiuz/labs/mintoolkit/nuxt-web-app:v1.0.0.