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fix(test): make tst-support_descriptors pass when /dev/null and /dev are on different filesystems (uos-debrebuild build failure) - #53

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fix/tst-support-descriptors-cross-device
Oct 24, 2026
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fix(test): make tst-support_descriptors pass when /dev/null and /dev are on different filesystems (uos-debrebuild build failure)#53
Zeno-sole merged 2 commits into
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fix/tst-support-descriptors-cross-device

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@Zeno-sole Zeno-sole commented Oct 24, 2026

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fix(test): tst-support_descriptors 在 /dev/null 与 /dev 异设备时失败（2.38-6deepin32）

失败现象

uos-debrebuild 重建 2.38-6deepin31 在 check 阶段失败（非编译错误），全部测试中仅一个不通过：

FAIL: support/tst-support_descriptors
error: tst-support_descriptors.c:141: not true: strstr (proc.out.buffer, expected) != NULL
汇总：5168 PASS / 1 FAIL → make check Error 1 → dpkg-buildpackage exit 2

根因

该流水线使用 sbuild --chroot-mode=unshare，chroot 内 /dev/null 是从另一个文件系统 bind-mount 的（st_dev 0:6），而 /dev 目录在 rootfs 上（st_dev 0:34）。

测试的 subprocess_changed_descriptor 把 fd 3 从 /dev/null 换成 /dev，support_descriptors_check 在两行预期诊断之间多打印了一行：

error: descriptor 3 changed from "/dev/null" to "/dev"
error: descriptor 3 changed device from 0:6 to 0:34   ← 异设备时才出现
error: descriptor 3 changed ino from 4 to ...

测试用一条拼接的 strstr 同时匹配 "changed from … changed ino …"，插入行导致失配。普通构建系统 /dev/null 与 /dev 同设备，不出现该行，因此 OBS/常规 CI 不受影响。上游 master 至今未改这两个文件（无现成上游修复）。

修复

debian/patches/any/local-tst-support-descriptors-cross-device.diff：把拼接期望拆成两个独立子串匹配。诊断输出本身不变，仅测试对自身预期输出的匹配可容忍可选的 device 行。

验证（完整 glibc 2.38 源码构建 + 真实复现）

场景 未打补丁 打补丁后
常规环境（/dev/null 与 /dev 同设备） exit 0 exit 0
挂载命名空间内跨文件系统 bind /dev/null（复现 debrebuild chroot 条件） exit 1（错误签名与流水线逐字一致：changed device from 259:4 to 0:5 + :141 not true） exit 0（changed device 诊断照常打印并被校验）

复现方法：宿主 sudo unshare -m sh -c 'mount --bind /tmp/f /dev/null; …' 后直接以构建出的 ld.so 运行测试二进制。

影响面

  • 仅测试代码，不影响任何运行时行为；普通构建系统行为不变
  • 修复后 uos-debrebuild 流水线可完整重建 glibc

@Zeno-sole
fix(test): make tst-support_descriptors pass when /dev/null and /dev …
2211a3e 
…are on different filesystems

The uos-debrebuild pipeline failed to rebuild glibc 2.38-6deepin31 at
the check stage with a single failing test:

  FAIL: support/tst-support_descriptors
  error: tst-support_descriptors.c:141: not true: strstr (proc.out.buffer, expected) != NULL
  (summary: 5168 PASS, 1 FAIL -> make check Error -> dpkg-buildpackage exit 2)

Root cause: that chroot (sbuild --chroot-mode=unshare) bind-mounts
/dev/null from a different filesystem than /dev (st_dev 0:6 vs 0:34).
In subprocess_changed_descriptor the test changes fd 3 from /dev/null
to /dev, and support_descriptors_check then prints an extra

  error: descriptor 3 changed device from 0:6 to 0:34

line between the "changed from" and "changed ino" lines.  The test
matches both expected lines with one glued strstr, which no longer
matches.  On ordinary build systems /dev/null and /dev share st_dev,
so the extra line never appears there.

Fix (debian/patches/any/local-tst-support-descriptors-cross-device.diff):
split the glued expectation into two independent substring checks.  The
diagnostics printed by support_descriptors_check are unchanged; only the
test's matching of its own expected output becomes tolerant of the
optional device line.

Verified against a full glibc 2.38 source build:

- unpatched test: exit 0 normally; exit 1 (same error signature as the
  pipeline) inside a mount namespace with /dev/null bind-mounted from a
  different filesystem
- patched test: exit 0 in both environments, with the "changed device"
  diagnostic still being printed and checked

Log: fix the only failing self-test so glibc rebuilds complete in unshare-based chroots

Influence:
1. glibc 2.38-6deepin32 completes make check in the uos-debrebuild (unshare) environment; no behavior change elsewhere
2. The support_descriptors_check diagnostics are unchanged, only the test's own expectation matching is split
3. Ordinary build systems (/dev/null and /dev on the same filesystem) behave exactly as before

fix(test): 使 tst-support_descriptors 在 /dev/null 与 /dev 位于不同文件系统时也能通过

uos-debrebuild 流水线重建 glibc 2.38-6deepin31 在 check 阶段失败，仅一个
测试不通过：

  FAIL: support/tst-support_descriptors
  error: tst-support_descriptors.c:141: not true: strstr (...) != NULL
  （汇总：5168 PASS，1 FAIL → make check Error → dpkg-buildpackage 退出 2）

根因：该 chroot（sbuild --chroot-mode=unshare）的 /dev/null 是从与 /dev
不同的文件系统 bind-mount 而来（st_dev 0:6 vs 0:34）。测试在
subprocess_changed_descriptor 中把 fd 3 从 /dev/null 换成 /dev，
support_descriptors_check 会在 "changed from" 与 "changed ino" 两行之间
多打印一行：

  error: descriptor 3 changed device from 0:6 to 0:34

而测试用一条拼接的 strstr 同时匹配两行，遂失配。普通构建系统的
/dev/null 与 /dev 同设备，不会出现该行。

修复（debian/patches/any/local-tst-support-descriptors-cross-device.diff）：
把拼接期望拆成两个独立的子串匹配。support_descriptors_check 的诊断输出
不变，仅测试对自身预期输出的匹配可容忍可选的 device 行。

基于完整的 glibc 2.38 源码构建验证：

- 未打补丁：常规环境 exit 0；在挂载命名空间内将 /dev/null 跨文件系统
  bind-mount 后 exit 1（错误签名与流水线完全一致）
- 打补丁后：两种环境均 exit 0，"changed device" 诊断仍照常打印并校验

Log: 修复唯一失败的自检测试，使 glibc 在 unshare 类 chroot 中能完成重建

Influence:
1. glibc 2.38-6deepin32 在 uos-debrebuild（unshare）环境可完整通过 make check，其他环境无行为变化
2. support_descriptors_check 诊断输出不变，仅拆分测试自身的期望匹配
3. 普通构建系统（/dev/null 与 /dev 同文件系统）行为与之前完全一致

repo: glibc #master
@Zeno-sole

Zeno-sole commented Oct 24, 2026

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/integrate

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deepin-ci-robot commented Oct 24, 2026

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[APPROVALNOTIFIER] This PR is NOT APPROVED

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TAG Bot

TAG: 2.38-6deepin32
EXISTED: no
DISTRIBUTION: unstable

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AutoIntegrationPr Bot
auto integrate with pr url: deepin-community/Repository-Integration#4694
PrNumber: 4694
PrBranch: auto-integration-40103117126

@deepin-community-ci-bot deepin-community-ci-bot Bot mentioned this pull request Oct 24, 2026
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@Zeno-sole
fix(patch): regenerate tst-support_descriptors patch without fuzz and…
cfe1acf 
… with proper blank-context lines

dpkg-source applies patches with patch -t -F 0 (no fuzz allowed); the
previous version of the patch needed fuzz 1 for hunk 2 and had empty
lines instead of single-space blank context lines, which made
dpkg-source abort with 'Hunk #2 FAILED' / 'unexpected end of diff'.
Regenerate the body mechanically from the verified build tree so it is
byte-identical to GNU diff output: single hunk, exact line counts
(-128,20 +128,28), proper blank context markers.

Verified: patch -t -F 0 dry-run clean; full dpkg-source --before-build
applies the whole series including this patch with exit 0 and no
warnings; the applied file is byte-identical to the one used in the
end-to-end test verification (cross-device /dev/null: unpatched exit 1,
patched exit 0).
@Zeno-sole

Zeno-sole commented Oct 24, 2026

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已修复 patch 无法应用的问题（commit cfe1acf6）

失败原因有两点：

  1. dpkg-source 以 patch -t -F 0（禁 fuzz）应用补丁，而原版 hunk Apply any/local-revert-bz13979.diff #2 需要 fuzz 1 才能套上 → Hunk #2 FAILED；
  2. 补丁里的空白上下文行写成了空行，而 GNU diff 规范是单个前导空格，行数计数也少了一行（} 后的空上下文行）→ unexpected end of diff。

修复方式：从实际验证过的构建树机械重新生成 diff 体（单 hunk，精确计数 @@ -128,20 +128,28 @@，空白上下文行带前导空格），与 GNU diff 输出逐字节一致。

验证：

  • patch -t -F 0 -N --dry-run 干净通过；
  • 在纯净源码树上跑完整的 dpkg-source -i -I --before-build .（与 CI 失败命令同口径）：全 series 应用成功，exit 0，无任何警告；
  • 应用后的文件与此前端到端验证（异设备 /dev/null：未打补丁 exit 1、打补丁 exit 0）所用的文件 md5 完全一致（15ad600d…）。

@Zeno-sole

Zeno-sole commented Oct 24, 2026

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本地完整打包构建验证（cfe1acf6 之后）

在 uos:2501 容器内用 dpkg-buildpackage -us -uc -b -j16 对打补丁后的源码树做了完整构建：

  • dpkg-source 补丁应用（原 CI 失败点）：干净通过，无警告
  • 编译与 i386/x32 flavor 的 check：全部通过
  • 本体（amd64-libc）check 阶段：support/tst-support_descriptors PASS（流水线上唯一失败的测试；本地 5125 PASS）
  • 残留 6 个 FAIL 全部是 nptl gdb-printers 测试（Error: Response does not match the expected pattern = 容器 gdb 版本与打印机脚本不匹配）。这类测试在 debrebuild chroot 里因无 gdb 而记 UNSUPPORTED（流水线汇总中它们正是 UNSUPPORTED），不会导致失败——与本补丁无关

结论：在流水线等价环境（无 gdb）下，该补丁可使 glibc 构建全绿。

@Zeno-sole

Zeno-sole commented Oct 24, 2026

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/integrate

@Zeno-sole
Zeno-sole merged commit 4a162b1 into master Oct 24, 2026
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