Add notes to relevant tests.

These were out-of-band notes that can help provide additional context
and simplify automated imports.

PiperOrigin-RevId: 293525915

1 files changed, 38 insertions, 8 deletions

diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc
index 169b723eb..a23fdb58d 100644
--- a/test/syscalls/linux/proc.cc
+++ b/test/syscalls/linux/proc.cc
@@ -1352,13 +1352,19 @@ TEST(ProcPidSymlink, SubprocessZombied) {
 
   // FIXME(gvisor.dev/issue/164): Inconsistent behavior between gVisor and linux
   // on proc files.
-  // 4.17 & gVisor: Syscall succeeds and returns 1
+  //
+  // ~4.3: Syscall fails with EACCES.
+  // 4.17 & gVisor: Syscall succeeds and returns 1.
+  //
   // EXPECT_THAT(ReadlinkWhileZombied("ns/pid", buf, sizeof(buf)),
   //            SyscallFailsWithErrno(EACCES));
 
   // FIXME(gvisor.dev/issue/164): Inconsistent behavior between gVisor and linux
   // on proc files.
-  // 4.17 &  gVisor: Syscall succeeds and returns 1.
+  //
+  // ~4.3: Syscall fails with EACCES.
+  // 4.17 & gVisor: Syscall succeeds and returns 1.
+  //
   // EXPECT_THAT(ReadlinkWhileZombied("ns/user", buf, sizeof(buf)),
   //            SyscallFailsWithErrno(EACCES));
 }
@@ -1431,8 +1437,12 @@ TEST(ProcPidFile, SubprocessRunning) {
 TEST(ProcPidFile, SubprocessZombie) {
   char buf[1];
 
-  // 4.17: Succeeds and returns 1
-  // gVisor: Succeeds and returns 0
+  // FIXME(gvisor.dev/issue/164): Loosen requirement due to inconsistent
+  // behavior on different kernels.
+  //
+  // ~4.3: Succeds and returns 0.
+  // 4.17: Succeeds and returns 1.
+  // gVisor: Succeeds and returns 0.
   EXPECT_THAT(ReadWhileZombied("auxv", buf, sizeof(buf)), SyscallSucceeds());
 
   EXPECT_THAT(ReadWhileZombied("cmdline", buf, sizeof(buf)),
@@ -1458,7 +1468,10 @@ TEST(ProcPidFile, SubprocessZombie) {
 
   // FIXME(gvisor.dev/issue/164): Inconsistent behavior between gVisor and linux
   // on proc files.
+  //
+  // ~4.3: Fails and returns EACCES.
   // gVisor & 4.17: Succeeds and returns 1.
+  //
   // EXPECT_THAT(ReadWhileZombied("io", buf, sizeof(buf)),
   //          SyscallFailsWithErrno(EACCES));
 }
@@ -1467,9 +1480,12 @@ TEST(ProcPidFile, SubprocessZombie) {
 TEST(ProcPidFile, SubprocessExited) {
   char buf[1];
 
-  // FIXME(gvisor.dev/issue/164): Inconsistent behavior between kernels
+  // FIXME(gvisor.dev/issue/164): Inconsistent behavior between kernels.
+  //
+  // ~4.3: Fails and returns ESRCH.
   // gVisor: Fails with ESRCH.
   // 4.17: Succeeds and returns 1.
+  //
   // EXPECT_THAT(ReadWhileExited("auxv", buf, sizeof(buf)),
   //            SyscallFailsWithErrno(ESRCH));
 
@@ -1641,7 +1657,7 @@ TEST(ProcTask, KilledThreadsDisappear) {
   EXPECT_NO_ERRNO(DirContainsExactly("/proc/self/task",
                                      TaskFiles(initial, {child1.Tid()})));
 
-  // Stat child1's task file.
+  // Stat child1's task file. Regression test for b/32097707.
   struct stat statbuf;
   const std::string child1_task_file =
       absl::StrCat("/proc/self/task/", child1.Tid());
@@ -1669,7 +1685,7 @@ TEST(ProcTask, KilledThreadsDisappear) {
   EXPECT_NO_ERRNO(EventuallyDirContainsExactly(
       "/proc/self/task", TaskFiles(initial, {child3.Tid(), child5.Tid()})));
 
-  // Stat child1's task file again.  This time it should fail.
+  // Stat child1's task file again.  This time it should fail. See b/32097707.
   EXPECT_THAT(stat(child1_task_file.c_str(), &statbuf),
               SyscallFailsWithErrno(ENOENT));
 
@@ -1824,7 +1840,7 @@ TEST(ProcSysVmOvercommitMemory, HasNumericValue) {
 }
 
 // Check that link for proc fd entries point the target node, not the
-// symlink itself.
+// symlink itself. Regression test for b/31155070.
 TEST(ProcTaskFd, FstatatFollowsSymlink) {
   const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
   const FileDescriptor fd =
@@ -1883,6 +1899,20 @@ TEST(ProcMounts, IsSymlink) {
   EXPECT_EQ(link, "self/mounts");
 }
 
+TEST(ProcSelfMountinfo, RequiredFieldsArePresent) {
+  auto mountinfo =
+      ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/mountinfo"));
+  EXPECT_THAT(
+      mountinfo,
+      AllOf(
+          // Root mount.
+          ContainsRegex(
+              R"([0-9]+ [0-9]+ [0-9]+:[0-9]+ / / (rw|ro).*- \S+ \S+ (rw|ro)\S*)"),
+          // Proc mount - always rw.
+          ContainsRegex(
+              R"([0-9]+ [0-9]+ [0-9]+:[0-9]+ / /proc rw.*- \S+ \S+ rw\S*)")));
+}
+
 // Check that /proc/self/mounts looks something like a real mounts file.
 TEST(ProcSelfMounts, RequiredFieldsArePresent) {
   auto mounts = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/mounts"));