diff --git a/addrcheck/ac_main.c b/addrcheck/ac_main.c
index 511c7c5..eb8a31d 100644
--- a/addrcheck/ac_main.c
+++ b/addrcheck/ac_main.c
@@ -1182,8 +1182,12 @@
 
 Bool SK_(cheap_sanity_check) ( void )
 {
-   if (IS_DISTINGUISHED_SM(primary_map[0]) && 
-       IS_DISTINGUISHED_SM(primary_map[65535]))
+   if (IS_DISTINGUISHED_SM(primary_map[0])
+       /* kludge: kernel drops a page up at top of address range for
+          magic "optimized syscalls", so we can no longer check the
+          highest page */
+       /* && IS_DISTINGUISHED_SM(primary_map[65535]) */
+      )
       return True;
    else
       return False;
diff --git a/coregrind/valgrind.in b/coregrind/valgrind.in
index 14c1409..fcdbd5b 100755
--- a/coregrind/valgrind.in
+++ b/coregrind/valgrind.in
@@ -83,6 +83,14 @@
 
 export VG_ARGS
 
+# Red Hat Linux 9 uses NPTL, which has a kernel interface 
+# unlike the linuxthreads interface valgrind expects. we can
+# tell the dynamic loader to disable this interface using
+# an environment variable.
+
+LD_ASSUME_KERNEL=2.2.5
+export LD_ASSUME_KERNEL 
+
 # A bit subtle.  The LD_PRELOAD added entry must be absolute
 # and not depend on LD_LIBRARY_PATH.  This is so that we can
 # mess with LD_LIBRARY_PATH for child processes, which makes
diff --git a/coregrind/vg_include.h b/coregrind/vg_include.h
index f309dc1..018e88a 100644
--- a/coregrind/vg_include.h
+++ b/coregrind/vg_include.h
@@ -1320,6 +1320,11 @@
    client's argc, argv and envp are deduced. */
 extern Addr   VG_(esp_at_startup);
 
+/* Indicates presence, and holds address of client's sysinfo page, a
+   feature of some modern kernels used to provide vsyscalls, etc. */
+extern Bool VG_(sysinfo_page_exists);
+extern Addr VG_(sysinfo_page_addr);
+
 /* Remove valgrind.so and skin's .so from a LD_PRELOAD=... string so child
    processes don't get traced into.  Also mess up $libdir/valgrind so that
    our libpthread.so disappears from view. */
diff --git a/coregrind/vg_kerneliface.h b/coregrind/vg_kerneliface.h
index 7784571..67b61a5 100644
--- a/coregrind/vg_kerneliface.h
+++ b/coregrind/vg_kerneliface.h
@@ -353,6 +353,7 @@
    Logic from     /usr/src/linux-2.4.9-31/fs/binfmt_elf.c
                   and its counterpart in the 2.2.14 kernel sources 
                   in Red Hat 6.2.  */
+#define VKI_AT_SYSINFO 32   /* address of system info page */
 #define VKI_AT_CLKTCK 17    /* frequency at which times() increments */
 #define VKI_AT_HWCAP  16    /* arch dependent hints at CPU capabilities */
 #define VKI_AT_BASE   7     /* base address of interpreter */
diff --git a/coregrind/vg_main.c b/coregrind/vg_main.c
index a308c2b..eebdec6 100644
--- a/coregrind/vg_main.c
+++ b/coregrind/vg_main.c
@@ -496,6 +496,11 @@
 /* Holds client's %esp at the point we gained control. */
 Addr VG_(esp_at_startup);
 
+/* Indicates presence, and holds address of client's sysinfo page, a
+   feature of some modern kernels used to provide vsyscalls, etc. */
+Bool VG_(sysinfo_page_exists) = False;
+Addr VG_(sysinfo_page_addr) = 0;
+
 /* As deduced from VG_(esp_at_startup), the client's argc, argv[] and
    envp[] as extracted from the client's stack at startup-time. */
 Int    VG_(client_argc);
@@ -725,6 +730,18 @@
        if (sp[2] == VKI_AT_CLKTCK
            && sp[0] == VKI_AT_PAGESZ
            && sp[-2] == VKI_AT_HWCAP
+           && sp[-4] == VKI_AT_SYSINFO
+           && sp[-4-1] == 0) {
+          if (0)
+             VG_(printf)("Looks like you've got a 2.4.X kernel with "
+                         "a sysinfo page at %x here.\n", sp[-3]);
+	  VG_(sysinfo_page_exists) = True;
+	  VG_(sysinfo_page_addr) = sp[-3];
+          sp -= 4;
+       } else
+       if (sp[2] == VKI_AT_CLKTCK
+           && sp[0] == VKI_AT_PAGESZ
+           && sp[-2] == VKI_AT_HWCAP
            && sp[-4] == VKI_AT_USER_AUX_SEGMENT
            && sp[-4-1] == 0) {
           if (0)
diff --git a/coregrind/vg_memory.c b/coregrind/vg_memory.c
index f2429ec..7b83fa3 100644
--- a/coregrind/vg_memory.c
+++ b/coregrind/vg_memory.c
@@ -211,6 +211,15 @@
 
    /* 4 */
    VG_(init_dataseg_end_for_brk)();
+
+   /* kludge: some newer kernels place a "sysinfo" page up high, with
+      vsyscalls in it, and possibly some other stuff in the future. */
+   if (VG_(sysinfo_page_exists)) {
+      VG_(new_exe_segment)( VG_(sysinfo_page_addr), 4096 );
+      VG_TRACK( new_mem_startup, VG_(sysinfo_page_addr), 4096, 
+                True, True, True );
+     }
+
 }
 
 
diff --git a/helgrind/hg_main.c b/helgrind/hg_main.c
index 8859aff..190e906 100644
--- a/helgrind/hg_main.c
+++ b/helgrind/hg_main.c
@@ -1872,8 +1872,12 @@
 
 Bool SK_(cheap_sanity_check) ( void )
 {
-   if (VGE_IS_DISTINGUISHED_SM(primary_map[0]) && 
-       VGE_IS_DISTINGUISHED_SM(primary_map[65535]))
+   if (VGE_IS_DISTINGUISHED_SM(primary_map[0])
+       /* kludge: kernel drops a page up at top of address range for
+          magic "optimized syscalls", so we can no longer check the
+          highest page */
+       /* && VGE_IS_DISTINGUISHED_SM(primary_map[65535]) */
+      )
       return True;
    else
       return False;
diff --git a/memcheck/mc_main.c b/memcheck/mc_main.c
index 78779bb..2a4daaa 100644
--- a/memcheck/mc_main.c
+++ b/memcheck/mc_main.c
@@ -1349,8 +1349,12 @@
 
 Bool SK_(cheap_sanity_check) ( void )
 {
-   if (IS_DISTINGUISHED_SM(primary_map[0]) && 
-       IS_DISTINGUISHED_SM(primary_map[65535]))
+   if (IS_DISTINGUISHED_SM(primary_map[0])
+       /* kludge: kernel drops a page up at top of address range for
+          magic "optimized syscalls", so we can no longer check the
+          highest page */
+       /* && IS_DISTINGUISHED_SM(primary_map[65535]) */
+      )
       return True;
    else
       return False;