commit 8380ca5833ef2a11bf0162f2290f4f8c85ce3b90
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Mar 31 13:53:34 2021 -0300

    linux: Normalize and return timeout on select (BZ #27651)
    
    The commit 2433d39b697, which added time64 support to select, changed
    the function to use __NR_pselect6 (or __NR_pelect6_time64) on all
    architectures.  However, on architectures where the symbol was
    implemented with __NR_select the kernel normalizes the passed timeout
    instead of return EINVAL.  For instance, the input timeval
    { 0, 5000000 } is interpreted as { 5, 0 }.
    
    And as indicated by BZ #27651, this semantic seems to be expected
    and changing it results in some performance issues (most likely
    the program does not check the return code and keeps issuing
    select with unormalized tv_usec argument).
    
    To avoid a different semantic depending whether which syscall the
    architecture used to issue, select now always normalize the timeout
    input.  This is a slight change for some ABIs (for instance aarch64).
    
    Checked on x86_64-linux-gnu and i686-linux-gnu.
    
    (cherry picked from commit 9d7c5cc38e58fb0923e88901f87174a511b61552)

diff --git a/include/time.h b/include/time.h
index caf2af5e74ed6179..e0636132a6ee3fe9 100644
--- a/include/time.h
+++ b/include/time.h
@@ -502,6 +502,11 @@ time_now (void)
   __clock_gettime (TIME_CLOCK_GETTIME_CLOCKID, &ts);
   return ts.tv_sec;
 }
+
+#define NSEC_PER_SEC    1000000000L  /* Nanoseconds per second.  */
+#define USEC_PER_SEC    1000000L     /* Microseconds per second.  */
+#define NSEC_PER_USEC   1000L        /* Nanoseconds per microsecond.  */
+
 #endif
 
 #endif
diff --git a/misc/tst-select.c b/misc/tst-select.c
index 5ad057cd51d0f45c..534105b50020fa44 100644
--- a/misc/tst-select.c
+++ b/misc/tst-select.c
@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <support/capture_subprocess.h>
 #include <support/check.h>
+#include <support/support.h>
 #include <support/timespec.h>
 #include <support/xunistd.h>
 #include <support/xtime.h>
@@ -47,6 +48,12 @@ do_test_child (void *clousure)
   int r = select (args->fds[0][0] + 1, &rfds, NULL, NULL, &args->tmo);
   TEST_COMPARE (r, 0);
 
+  if (support_select_modifies_timeout ())
+    {
+      TEST_COMPARE (args->tmo.tv_sec, 0);
+      TEST_COMPARE (args->tmo.tv_usec, 0);
+    }
+
   TEST_TIMESPEC_NOW_OR_AFTER (CLOCK_REALTIME, ts);
 
   xwrite (args->fds[1][1], "foo", 3);
@@ -69,6 +76,16 @@ do_test (void)
 				      sc_allow_none);
   }
 
+  if (support_select_normalizes_timeout ())
+    {
+      /* This is handled as 1 second instead of failing with EINVAL.  */
+      args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 1000000 };
+      struct support_capture_subprocess result;
+      result = support_capture_subprocess (do_test_child, &args);
+      support_capture_subprocess_check (&result, "tst-select-child", 0,
+					sc_allow_none);
+    }
+
   /* Same as before, but simulating polling.  */
   args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 0 };
   {
diff --git a/sunrpc/svcauth_des.c b/sunrpc/svcauth_des.c
index 7607abc8186813f6..25a85c90970d4ced 100644
--- a/sunrpc/svcauth_des.c
+++ b/sunrpc/svcauth_des.c
@@ -58,7 +58,6 @@
 
 #define debug(msg)		/*printf("svcauth_des: %s\n", msg) */
 
-#define USEC_PER_SEC ((uint32_t) 1000000L)
 #define BEFORE(t1, t2) timercmp(t1, t2, <)
 
 /*
diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
index 415aa87d3c87d70c..3b67ff44765ededf 100644
--- a/sysdeps/unix/sysv/linux/select.c
+++ b/sysdeps/unix/sysv/linux/select.c
@@ -33,12 +33,34 @@ int
 __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 	    struct __timeval64 *timeout)
 {
-  struct __timespec64 ts64, *pts64 = NULL;
-  if (timeout != NULL)
+  __time64_t s = timeout != NULL ? timeout->tv_sec : 0;
+  int32_t us = timeout != NULL ? timeout->tv_usec : 0;
+  int32_t ns;
+
+  if (s < 0 || us < 0)
+    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
+
+  /* Normalize the timeout, as legacy Linux __NR_select and __NR__newselect.
+     Different than syscall, it also handle possible overflow.  */
+  if (us / USEC_PER_SEC > INT64_MAX - s)
     {
-      ts64 = timeval64_to_timespec64 (*timeout);
-      pts64 = &ts64;
+      s = INT64_MAX;
+      ns = NSEC_PER_SEC - 1;
     }
+  else
+    {
+      s += us / USEC_PER_SEC;
+      us = us % USEC_PER_SEC;
+      ns = us * NSEC_PER_USEC;
+    }
+
+  struct __timespec64 ts64, *pts64 = NULL;
+   if (timeout != NULL)
+     {
+       ts64.tv_sec = s;
+       ts64.tv_nsec = ns;
+       pts64 = &ts64;
+     }
 
 #ifndef __NR_pselect6_time64
 # define __NR_pselect6_time64 __NR_pselect6
@@ -52,10 +74,10 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
          (though the pselect() glibc call suppresses this behavior).
          Since select() on Linux has the same behavior as the pselect6
          syscall, we update the timeout here.  */
-      if (r == 0 || errno != ENOSYS)
+      if (r >= 0 || errno != ENOSYS)
 	{
 	  if (timeout != NULL)
-	    TIMEVAL_TO_TIMESPEC (timeout, &ts64);
+	    TIMESPEC_TO_TIMEVAL (timeout, &ts64);
 	  return r;
 	}
 
@@ -64,14 +86,15 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 
 #ifndef __ASSUME_TIME64_SYSCALLS
   struct timespec ts32, *pts32 = NULL;
-  if (timeout != NULL)
+  if (pts64 != NULL)
     {
-      if (! in_time_t_range (timeout->tv_sec))
+      if (! in_time_t_range (pts64->tv_sec))
 	{
 	  __set_errno (EINVAL);
 	  return -1;
 	}
-      ts32 = valid_timespec64_to_timespec (ts64);
+      ts32.tv_sec = s;
+      ts32.tv_nsec = ns;
       pts32 = &ts32;
     }
 # ifndef __ASSUME_PSELECT