MDEV-24841 Build error with MSAN use-of-uninitialized-value in comp_err

The MemorySanitizer implementation in clang includes some built-in
instrumentation (interceptors) for GNU libc. In GNU libc 2.33, the
interface to the stat() family of functions was changed. Until the
MemorySanitizer interceptors are adjusted, any MSAN code builds
will act as if that the stat() family of functions failed to initialize
the struct stat.

A fix was applied in
https://reviews.llvm.org/rG4e1a6c07052b466a2a1cd0c3ff150e4e89a6d87a
but it fails to cover the 64-bit variants of the calls.

For now, let us work around the MemorySanitizer bug by defining
and using the macro MSAN_STAT_WORKAROUND().

include/my_valgrind.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2010, 2020, MariaDB Corporation.
+/* Copyright (C) 2010, 2022, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -37,6 +37,11 @@
 # define MEM_GET_VBITS(a,b,len) __msan_copy_shadow(b,a,len)
 # define MEM_SET_VBITS(a,b,len) __msan_copy_shadow(a,b,len)
 # define REDZONE_SIZE 8
+# ifdef __linux__
+#  define MSAN_STAT_WORKAROUND(st) MEM_MAKE_DEFINED(st, sizeof(*st))
+# else
+#  define MSAN_STAT_WORKAROUND(st) ((void) 0)
+# endif
 #elif defined(HAVE_VALGRIND_MEMCHECK_H) && defined(HAVE_valgrind)
 # include <valgrind/memcheck.h>
 # define HAVE_MEM_CHECK
@@ -49,6 +54,7 @@
 # define MEM_GET_VBITS(a,b,len) VALGRIND_GET_VBITS(a,b,len)
 # define MEM_SET_VBITS(a,b,len) VALGRIND_SET_VBITS(a,b,len)
 # define REDZONE_SIZE 8
+# define MSAN_STAT_WORKAROUND(st) ((void) 0)
 #elif defined(__SANITIZE_ADDRESS__) && (!defined(_MSC_VER) || defined (__clang__))
 # include <sanitizer/asan_interface.h>
 /* How to do manual poisoning:
@@ -62,6 +68,7 @@ https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning */
 # define MEM_CHECK_DEFINED(a,len) ((void) 0)
 # define MEM_GET_VBITS(a,b,len) ((void) 0)
 # define MEM_SET_VBITS(a,b,len) ((void) 0)
+# define MSAN_STAT_WORKAROUND(st) ((void) 0)
 # define REDZONE_SIZE 8
 #else
 # define MEM_UNDEFINED(a,len) ((void) 0)
@@ -73,6 +80,7 @@ https://github.com/google/sanitizers/wiki/AddressSanitizerManualPoisoning */
 # define MEM_GET_VBITS(a,b,len) ((void) 0)
 # define MEM_SET_VBITS(a,b,len) ((void) 0)
 # define REDZONE_SIZE 0
+# define MSAN_STAT_WORKAROUND(st) ((void) 0)
 #endif /* __has_feature(memory_sanitizer) */
 
 #ifdef HAVE_valgrind

mysys/my_lib.c

@@ -1,5 +1,5 @@
 /* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
-   Copyright (c) 2008, 2020, MariaDB Corporation.
+   Copyright (c) 2008, 2022, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -350,11 +350,14 @@ MY_STAT *my_stat(const char *path, MY_STAT *stat_area, myf my_flags)
                                            my_flags)))
       goto error;
 #ifndef _WIN32
-    if (! stat((char *) path, (struct stat *) stat_area) )
+  if (!stat((char *) path, (struct stat *) stat_area))
-      DBUG_RETURN(stat_area);
+  {
+    MSAN_STAT_WORKAROUND(stat_area);
+    DBUG_RETURN(stat_area);
+  }
 #else
-    if (! my_win_stat(path, stat_area) )
+  if (!my_win_stat(path, stat_area))
-      DBUG_RETURN(stat_area);
+    DBUG_RETURN(stat_area);
 #endif
   DBUG_PRINT("error",("Got errno: %d from stat", errno));
   my_errno= errno;

mysys/my_symlink.c

@@ -1,6 +1,6 @@
 /*
    Copyright (c) 2001, 2011, Oracle and/or its affiliates
-   Copyright (c) 2010, 2017, MariaDB
+   Copyright (c) 2010, 2022, MariaDB
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -113,7 +113,10 @@ int my_is_symlink(const char *filename __attribute__((unused)))
 {
 #if defined (HAVE_LSTAT) && defined (S_ISLNK)
   struct stat stat_buff;
-  return !lstat(filename, &stat_buff) && S_ISLNK(stat_buff.st_mode);
+  if (lstat(filename, &stat_buff))
+    return 0;
+  MSAN_STAT_WORKAROUND(&stat_buff);
+  return !!S_ISLNK(stat_buff.st_mode);
 #elif defined (_WIN32)
   DWORD dwAttr = GetFileAttributes(filename);
   return (dwAttr != INVALID_FILE_ATTRIBUTES) &&

sql/datadict.cc

@@ -128,6 +128,8 @@ Table_type dd_frm_type(THD *thd, char *path, LEX_CSTRING *engine_name)
     if (mysql_file_fstat(file, &state, MYF(MY_WME)))
       goto err;
 
+    MSAN_STAT_WORKAROUND(&state);
+
     if (mysql_file_seek(file, 0, SEEK_SET, MYF(MY_WME)))
       goto err;
 

sql/discover.cc

@@ -1,5 +1,5 @@
 /* Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
-   Copyright (c) 2009, 2020, MariaDB Corporation.
+   Copyright (c) 2009, 2022, MariaDB Corporation.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -72,6 +72,7 @@ int readfrm(const char *name, const uchar **frmdata, size_t *len)
   error= 2;
   if (mysql_file_fstat(file, &state, MYF(0)))
     goto err;
+  MSAN_STAT_WORKAROUND(&state);
   read_len= (size_t)MY_MIN(FRM_MAX_SIZE, state.st_size); // safety
 
   // Read whole frm file

sql/parse_file.cc

@@ -415,6 +415,8 @@ sql_parse_prepare(const LEX_CSTRING *file_name, MEM_ROOT *mem_root,
     DBUG_RETURN(0);
   }
 
+  MSAN_STAT_WORKAROUND(&stat_info);
+
   if (stat_info.st_size > INT_MAX-1)
   {
     my_error(ER_FPARSER_TOO_BIG_FILE, MYF(0), file_name->str);

storage/innobase/os/os0file.cc

@@ -953,7 +953,7 @@ os_file_status_posix(
 
 	if (!ret) {
 		/* file exists, everything OK */
-
+		MSAN_STAT_WORKAROUND(&statinfo);
 	} else if (errno == ENOENT || errno == ENOTDIR || errno == ENAMETOOLONG) {
 		/* file does not exist */
 		return(true);
@@ -1548,8 +1548,10 @@ bool os_file_close_func(os_file_t file)
 os_offset_t
 os_file_get_size(os_file_t file)
 {
-	struct stat statbuf;
+  struct stat statbuf;
-	return fstat(file, &statbuf) ? os_offset_t(-1) : statbuf.st_size;
+  if (fstat(file, &statbuf)) return os_offset_t(-1);
+  MSAN_STAT_WORKAROUND(&statbuf);
+  return statbuf.st_size;
 }
 
 /** Gets a file size.
@@ -1566,6 +1568,7 @@ os_file_get_size(
 	int	ret = stat(filename, &s);
 
 	if (ret == 0) {
+		MSAN_STAT_WORKAROUND(&s);
 		file_size.m_total_size = s.st_size;
 		/* st_blocks is in 512 byte sized blocks */
 		file_size.m_alloc_size = s.st_blocks * 512;
@@ -1610,6 +1613,8 @@ os_file_get_status_posix(
 		return(DB_FAIL);
 	}
 
+	MSAN_STAT_WORKAROUND(statinfo);
+
 	switch (statinfo->st_mode & S_IFMT) {
 	case S_IFDIR:
 		stat_info->type = OS_FILE_TYPE_DIR;
@@ -3300,6 +3305,7 @@ fallback:
 		if (fstat(file, &statbuf)) {
 			err = errno;
 		} else {
+			MSAN_STAT_WORKAROUND(&statbuf);
 			os_offset_t current_size = statbuf.st_size;
 			if (current_size >= size) {
 				return true;
@@ -4186,6 +4192,7 @@ void fil_node_t::find_metadata(os_file_t file
 #else
 	struct stat sbuf;
 	if (!statbuf && !fstat(file, &sbuf)) {
+		MSAN_STAT_WORKAROUND(&sbuf);
 		statbuf = &sbuf;
 	}
 	if (statbuf) {
@@ -4229,6 +4236,7 @@ bool fil_node_t::read_page0()
 	if (fstat(handle, &statbuf)) {
 		return false;
 	}
+	MSAN_STAT_WORKAROUND(&statbuf);
 	os_offset_t size_bytes = statbuf.st_size;
 #else
 	os_offset_t size_bytes = os_file_get_size(handle);

strings/my_vsnprintf.c

@@ -704,10 +704,11 @@ size_t my_vsnprintf_ex(CHARSET_INFO *cs, char *to, size_t n,
     }
     else if (*fmt == 'f' || *fmt == 'g')
     {
+      double d;
 #if __has_feature(memory_sanitizer)         /* QQ: MSAN has double trouble? */
       __msan_check_mem_is_initialized(ap, sizeof(double));
 #endif
-      double d= va_arg(ap, double);
+      d= va_arg(ap, double);
 #if __has_feature(memory_sanitizer)        /* QQ: MSAN has double trouble? */
       __msan_unpoison(&d, sizeof(double));
 #endif