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authorAlexey Makhalov <amakhalov@vmware.com>2017-09-27 02:44:09 +0530
committerSiddhesh Poyarekar <siddhesh@sourceware.org>2017-09-27 02:44:09 +0530
commitcebcb9f864d4ca29e155363e71b7de6826d13cf1 (patch)
tree5e2b25a46cbcb31b4a5e280db71641b8d7df22bf /elf
parent592d5c75392e1da170050a4999af0618c4865aed (diff)
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Fix range check in do_tunable_update_val
Current implementation of tunables does not set arena_max and arena_test
values. Any value provided by glibc.malloc.arena_max and
glibc.malloc.arena_test parameters is ignored.

These tunables have minval value set to 1 (see elf/dl-tunables.list file)
and undefined maxval value. In that case default value (which is 0. see
scripts/gen-tunables.awk) is being used to set maxval.

For instance, generated tunable_list[] entry for arena_max is:
(gdb) p *cur
$1 = {name = 0x7ffff7df6217 "glibc.malloc.arena_max",
 type = {type_code = TUNABLE_TYPE_SIZE_T, min = 1, max = 0},
  val = {numval = 0, strval = 0x0}, initialized = false,
   security_level = TUNABLE_SECLEVEL_SXID_IGNORE,
    env_alias = 0x7ffff7df622e "MALLOC_ARENA_MAX"}

As a result, any value of glibc.malloc.arena_max is ignored by
TUNABLE_SET_VAL_IF_VALID_RANGE macro
  __type min = (__cur)->type.min;                    <- initialized to 1
  __type max = (__cur)->type.max;                    <- initialized to 0!
  if (min == max)                                    <- false
    {
      min = __default_min;
      max = __default_max;
    }
  if ((__type) (__val) >= min && (__type) (val) <= max)  <- false
    {
      (__cur)->val.numval = val;
      (__cur)->initialized = true;
    }

Assigning correct min/max values at a build time fixes a problem.
Plus, a bit of optimization: Setting of default min/max values for the
given type at a run time might be eliminated.

	* elf/dl-tunables.c (do_tunable_update_val): Range checking fix.
	* scripts/gen-tunables.awk: Set unspecified minval and/or maxval
	values to correct default value for given type.
Diffstat (limited to 'elf')
-rw-r--r--elf/dl-tunables.c15
1 files changed, 4 insertions, 11 deletions
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index b964a09413..cc2c637543 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -89,18 +89,11 @@ get_next_env (char **envp, char **name, size_t *namelen, char **val,
   return NULL;
 }
 
-#define TUNABLE_SET_VAL_IF_VALID_RANGE(__cur, __val, __type, __default_min, \
-				       __default_max)			      \
+#define TUNABLE_SET_VAL_IF_VALID_RANGE(__cur, __val, __type)		      \
 ({									      \
   __type min = (__cur)->type.min;					      \
   __type max = (__cur)->type.max;					      \
 									      \
-  if (min == max)							      \
-    {									      \
-      min = __default_min;						      \
-      max = __default_max;						      \
-    }									      \
-									      \
   if ((__type) (__val) >= min && (__type) (val) <= max)			      \
     {									      \
       (__cur)->val.numval = val;					      \
@@ -120,17 +113,17 @@ do_tunable_update_val (tunable_t *cur, const void *valp)
     {
     case TUNABLE_TYPE_INT_32:
 	{
-	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, int64_t, INT32_MIN, INT32_MAX);
+	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, int64_t);
 	  break;
 	}
     case TUNABLE_TYPE_UINT_64:
 	{
-	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t, 0, UINT64_MAX);
+	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t);
 	  break;
 	}
     case TUNABLE_TYPE_SIZE_T:
 	{
-	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t, 0, SIZE_MAX);
+	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t);
 	  break;
 	}
     case TUNABLE_TYPE_STRING: