use mlock to determine hugepage RLIMIT_MEMLOCK soft resource limit is valid

Signed-off-by: Lv Ying <lvying6@huawei.com>
(cherry picked from commit e2b1c096a33d8130e739a6800ebae38db80a6346)

glibc.spec

@@ -66,7 +66,7 @@
 ##############################################################################
 Name: 	 	glibc
 Version: 	2.34
-Release: 	71
+Release: 	72
 Summary: 	The GNU libc libraries
 License:	%{all_license}
 URL: 		http://www.gnu.org/software/glibc/
@@ -229,6 +229,7 @@ Patch9016: 0001-elf-dynamic-linker-load-shared-object-use-hugepage-a.patch
 Patch9017: 0002-elf-ld.so-add-testcase-for-ld.so-load-shared-object-.patch
 Patch9018: 0003-elf-ld.so-use-special-mmap-for-hugepage-to-get-symbo.patch
 Patch9019: malloc-use-__get_nprocs-replace-__get_nprocs_sched.patch
+Patch9020: use-mlock-to-determine-hugepage-RLIMIT_MEMLOCK-soft-.patch
 
 Obsoletes: nscd < 2.35
 Provides: ldconfig rtld(GNU_HASH) bundled(gnulib)
@@ -1300,6 +1301,9 @@ fi
 %endif
 
 %changelog
+* Wed Mar 30 2022 Lv Ying <lvying6@huawei.com> - 2.34-72
+- use mlock to determine hugepage RLIMIT_MEMLOCK soft resource limit is valid 
+
 * Tue Mar 29 2022 Yang Yanchao <yangyanchao@huawei.com> - 2.34-71
 - mv libc.info.gz* to the package glibc-help
 

use-mlock-to-determine-hugepage-RLIMIT_MEMLOCK-soft-.patch

@@ -0,0 +1,73 @@
+From 3d68198a71050e5f96df0ac41bb1877e22240717 Mon Sep 17 00:00:00 2001
+From: Lv Ying <lvying6@huawei.com>
+Date: Tue, 21 Dec 2021 03:27:07 +0800
+Subject: [PATCH] use mlock to determine hugepage RLIMIT_MEMLOCK soft resource
+ limit is valid
+
+Signed-off-by: Lv Ying <lvying6@huawei.com>
+---
+ elf/dl-load.c                  |  1 -
+ elf/dl-map-segments-hugepage.h | 23 ++++++++++++++++++++++-
+ 2 files changed, 22 insertions(+), 2 deletions(-)
+
+diff --git a/elf/dl-load.c b/elf/dl-load.c
+index 1aa77fa2..2691eefa 100644
+--- a/elf/dl-load.c
++++ b/elf/dl-load.c
+@@ -1219,7 +1219,6 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
+     maplength = loadcmds[nloadcmds - 1].allocend - loadcmds[0].mapstart;
+ 
+ #ifdef HUGEPAGE_SHARED_LIB
+-#define ERRSTRING_BUF_LEN 1024
+     int hp_errcode = 0;
+     char hp_buf[ERRSTRING_BUF_LEN];
+     if ((GLRO(dl_debug_mask) & DL_HUGEPAGE_LIB_LARGE_IN_FLAG) ||
+diff --git a/elf/dl-map-segments-hugepage.h b/elf/dl-map-segments-hugepage.h
+index 37788ef9..ef36f9ad 100644
+--- a/elf/dl-map-segments-hugepage.h
++++ b/elf/dl-map-segments-hugepage.h
+@@ -22,6 +22,7 @@
+ #define SIZE_2MB 0x200000
+ #define MASK_2MB 0x1FFFFF
+ #define THRESHOLD 16
++#define ERRSTRING_BUF_LEN 1024
+ 
+ /*
+  * Find the first PT_LOAD segment with execute permission
+@@ -57,12 +58,32 @@ __mmap_reserved_area(const struct loadcmd loadcmds[], size_t nloadcmds,
+   /*
+    * Get 2MB aligned contiguous va space
+    * This va space can not be munmap in case of multi thread dlopen concurrently
++   * the prot can not be PROT_NONE, otherwise mlock always failed
+    */
+-  void *map_area_start = __mmap(0, *maparealen, PROT_NONE,
++  void *map_area_start = __mmap(0, *maparealen, PROT_READ,
+     MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB|(SHFIT_2MB << MAP_HUGE_SHIFT), -1, 0);
+   if (__glibc_unlikely (map_area_start == MAP_FAILED))
+     return MAP_FAILED;
+ 
++  /*
++   * use mlock to see if hugepage is beyond the RLIMIT_MEMLOCK soft resource limit
++   * when hugepage feature is enabled, however cgroup hugetlb.2MB.limit_in_bytes
++   * is set 0, subsequent hugepage mmap will return 0, actual page fault will
++   * send sigbus to this process
++   * the next mmap with MAP_FIXED flag will munlock this area
++   */
++  int mlock_errcode = 0;
++  char mlock_buf[ERRSTRING_BUF_LEN];
++  if (mlock(map_area_start, *maparealen) != 0)
++    {
++      mlock_errcode = errno;
++      if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))
++        _dl_debug_printf("mlock failed: [%lx-%lx) :%s\n", (unsigned long)map_area_start,
++            (unsigned long)map_area_start + *maparealen,
++            mlock_errcode ? __strerror_r (mlock_errcode, mlock_buf, sizeof mlock_buf) : "");
++      goto unmap_reserved_area;
++    }
++
+   /*
+    * Remap 2MB aligned contiguous va space into 4KB contiguous va space
+    * to avoid the tedious work of splitting hugepage into 4KB page
+-- 
+2.27.0
+