linux-user, fix: Hide helper threads through saved procfs fds - #419
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y347812075 wants to merge 1 commit into
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linux-user, fix: Hide helper threads through saved procfs fds#419y347812075 wants to merge 1 commit into
y347812075 wants to merge 1 commit into
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Chromium's namespace sandbox keeps procfs directory descriptors across a shared chroot. Once the absolute /proc path becomes unreachable, LATX no longer recognized /proc/self/task and exposed its host-only RCU helper in st_nlink. ChatGPT 42.3.0 then failed the zygote thread-count check and triggered INT3 unless launched with --no-sandbox. Recognize saved current-process task descriptors by comparing their procfs device and inode with ../../self/task. Apply the guest thread count to fstat, fstatat with AT_EMPTY_PATH, and statx while leaving other processes' task directories unchanged. Add a focused x86_64 guest regression and a native two-thread helper covering saved proc root and task descriptors, AT_EMPTY_PATH, statx, and the other-PID negative case. Validated with the focused procfs and namespace integration tests and three ChatGPT default-sandbox launches reaching "Launching app" without INT3. Signed-off-by: yuerengan <y347812075@163.com>
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Summary / 变更说明
sandbox chroot makes the absolute
/procpath unreachable.fstat,fstatat(AT_EMPTY_PATH), andstatx(AT_EMPTY_PATH)results for the currentprocess's
/proc/self/taskdirectory.../../self/taskdevice/inode matchingso another PID's task directory is never rewritten.
saved proc-root/task descriptors and the other-PID negative cases.
This fixes ChatGPT 42.3.0 / Chromium 151 zygote startup under the default
sandbox. Before the fix, LATX exposed a host-only helper as
st_nlink=4whileChromium expected
3, causing anINT3;--no-sandboxavoided that path.Validation / 验证
./latxbuild/build64.sh— passed.test-cef-procfs-chroot.sh— passed; coversfstat,fstatatandstatxfor saved self-task fds plus all three other-PID negative cases.
test-proc-thread-count.sh— passed.test-cef-userns-exec.sh— passed.test-cef-userns-nested.sh— passed.-Wall -Wextra -Werror— passed.scripts/checkpatch.pl— exit 0, no errors; one generic new-fileMAINTAINERS reminder.
Launching app, startedNetworkService, and did not trigger the originalINT3.Checklist / 检查项
CONTRIBUTING.md. / 我已阅读CONTRIBUTING.md。git commit -s). /每个提交都包含 DCO 签署（
git commit -s）。are not applicable. /
我已提供相关构建或测试结果，或说明了不适用的原因。