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authorRickard Green <[email protected]>2017-04-05 14:32:16 +0200
committerRickard Green <[email protected]>2017-04-07 15:02:10 +0200
commit8f452530e61b299d4d48f82f41ab5364723607ae (patch)
tree29bc2e4cfac2bcd5fdc4cdee4996a39350a1a32a /erts/emulator/beam
parent671d690debf653a6b1e86c3e7880b9c5640b1324 (diff)
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Stack guard for PCRE
Diffstat (limited to 'erts/emulator/beam')
-rw-r--r--erts/emulator/beam/beam_debug.c46
-rw-r--r--erts/emulator/beam/erl_bif_info.c15
-rw-r--r--erts/emulator/beam/erl_bif_re.c35
-rw-r--r--erts/emulator/beam/erl_init.c52
-rw-r--r--erts/emulator/beam/global.h15
-rw-r--r--erts/emulator/beam/sys.h2
-rw-r--r--erts/emulator/beam/utils.c47
7 files changed, 197 insertions, 15 deletions
diff --git a/erts/emulator/beam/beam_debug.c b/erts/emulator/beam/beam_debug.c
index 21d336049f..d708cf89a7 100644
--- a/erts/emulator/beam/beam_debug.c
+++ b/erts/emulator/beam/beam_debug.c
@@ -731,3 +731,49 @@ print_op(fmtfn_t to, void *to_arg, int op, int size, BeamInstr* addr)
return size;
}
+
+
+#ifdef ERTS_SMP
+# define ERTS_STACK_LIMIT ((char *) ethr_get_stacklimit())
+#else
+# define ERTS_STACK_LIMIT ((char *) erts_scheduler_stack_limit)
+#endif
+
+/*
+ * The below functions is for testing of the stack
+ * limit functionality. They are intentionally
+ * written body recursive in order to prevent
+ * last call optimization...
+ */
+
+UWord
+erts_check_stack_recursion_downwards(char *start_c)
+{
+ char *limit = ERTS_STACK_LIMIT;
+ char c;
+ UWord res;
+ if (erts_check_below_limit(&c, limit + 1024))
+ return (char *) erts_ptr_id(start_c) - (char *) erts_ptr_id(&c);
+ res = erts_check_stack_recursion_downwards(start_c);
+ erts_ptr_id(&c);
+ return res;
+}
+
+UWord
+erts_check_stack_recursion_upwards(char *start_c)
+{
+ char *limit = ERTS_STACK_LIMIT;
+ char c;
+ UWord res;
+ if (erts_check_above_limit(&c, limit - 1024))
+ return (char *) erts_ptr_id(&c) - (char *) erts_ptr_id(start_c);
+ res = erts_check_stack_recursion_upwards(start_c);
+ erts_ptr_id(&c);
+ return res;
+}
+
+int
+erts_is_above_stack_limit(char *ptr)
+{
+ return (char *) ptr > ERTS_STACK_LIMIT;
+}
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index 7bd45916f5..dd1299ca57 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -3674,6 +3674,21 @@ BIF_RETTYPE erts_debug_get_internal_state_1(BIF_ALIST_1)
BIF_RET(erts_sint64_to_big(value, &hp));
}
}
+ else if (ERTS_IS_ATOM_STR("stack_check", BIF_ARG_1)) {
+ UWord size;
+ char c;
+ if (erts_is_above_stack_limit(&c))
+ size = erts_check_stack_recursion_downwards(&c);
+ else
+ size = erts_check_stack_recursion_upwards(&c);
+ if (IS_SSMALL(size))
+ BIF_RET(make_small(size));
+ else {
+ Uint hsz = BIG_UWORD_HEAP_SIZE(size);
+ Eterm *hp = HAlloc(BIF_P, hsz);
+ BIF_RET(uword_to_big(size, hp));
+ }
+ }
}
else if (is_tuple(BIF_ARG_1)) {
Eterm* tp = tuple_val(BIF_ARG_1);
diff --git a/erts/emulator/beam/erl_bif_re.c b/erts/emulator/beam/erl_bif_re.c
index ff7746ce1d..35b196743f 100644
--- a/erts/emulator/beam/erl_bif_re.c
+++ b/erts/emulator/beam/erl_bif_re.c
@@ -64,12 +64,47 @@ static void erts_erts_pcre_stack_free(void *ptr) {
erts_free(ERTS_ALC_T_RE_STACK,ptr);
}
+#define ERTS_PCRE_STACK_MARGIN (10*1024)
+
+#ifdef ERTS_SMP
+# define ERTS_STACK_LIMIT ((char *) ethr_get_stacklimit())
+#else
+# define ERTS_STACK_LIMIT ((char *) erts_scheduler_stack_limit)
+#endif
+
+static int
+stack_guard_downwards(void)
+{
+ char *limit = ERTS_STACK_LIMIT;
+ char c;
+
+ ASSERT(limit);
+
+ return erts_check_below_limit(&c, limit + ERTS_PCRE_STACK_MARGIN);
+}
+
+static int
+stack_guard_upwards(void)
+{
+ char *limit = ERTS_STACK_LIMIT;
+ char c;
+
+ ASSERT(limit);
+
+ return erts_check_above_limit(&c, limit - ERTS_PCRE_STACK_MARGIN);
+}
+
void erts_init_bif_re(void)
{
+ char c;
erts_pcre_malloc = &erts_erts_pcre_malloc;
erts_pcre_free = &erts_erts_pcre_free;
erts_pcre_stack_malloc = &erts_erts_pcre_stack_malloc;
erts_pcre_stack_free = &erts_erts_pcre_stack_free;
+ if ((char *) erts_ptr_id(&c) > ERTS_STACK_LIMIT)
+ erts_pcre_stack_guard = stack_guard_downwards;
+ else
+ erts_pcre_stack_guard = stack_guard_upwards;
default_table = NULL; /* ISO8859-1 default, forced into pcre */
max_loop_limit = CONTEXT_REDS * LOOP_FACTOR;
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index e8b8739852..4e408e8305 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -61,6 +61,9 @@
#define ERTS_DEFAULT_NO_ASYNC_THREADS 10
+#define ERTS_DEFAULT_SCHED_STACK_SIZE 256
+#define ERTS_MIN_SCHED_STACK_SIZE 20
+
/*
* The variables below (prefixed with etp_) are for erts/etc/unix/etp-commands
* only. Do not remove even though they aren't used elsewhere in the emulator!
@@ -123,6 +126,8 @@ const Eterm etp_hole_marker = ERTS_HOLE_MARKER;
const Eterm etp_hole_marker = 0;
#endif
+static int modified_sched_thread_suggested_stack_size = 0;
+
/*
* Note about VxWorks: All variables must be initialized by executable code,
* not by an initializer. Otherwise a new instance of the emulator will
@@ -1231,24 +1236,38 @@ early_init(int *argc, char **argv) /*
}
#ifndef ERTS_SMP
+
+void *erts_scheduler_stack_limit;
+
+
static void set_main_stack_size(void)
{
- if (erts_sched_thread_suggested_stack_size > 0) {
+ char c;
+ UWord stacksize;
# if HAVE_DECL_GETRLIMIT && HAVE_DECL_SETRLIMIT && HAVE_DECL_RLIMIT_STACK
- struct rlimit rl;
- int bytes = erts_sched_thread_suggested_stack_size * sizeof(Uint) * 1024;
- if (getrlimit(RLIMIT_STACK, &rl) != 0 ||
- (rl.rlim_cur = bytes, setrlimit(RLIMIT_STACK, &rl) != 0)) {
- erts_fprintf(stderr, "failed to set stack size for scheduler "
- "thread to %d bytes\n", bytes);
- erts_usage();
- }
+ struct rlimit rl;
+ int bytes;
+ stacksize = erts_sched_thread_suggested_stack_size * sizeof(Uint) * 1024;
+ /* Add some extra pages... neede by some systems... */
+ bytes = (int) stacksize + 3*erts_sys_get_page_size();
+ if (getrlimit(RLIMIT_STACK, &rl) != 0 ||
+ (rl.rlim_cur = bytes, setrlimit(RLIMIT_STACK, &rl) != 0)) {
+ erts_fprintf(stderr, "failed to set stack size for scheduler "
+ "thread to %d bytes\n", bytes);
+ erts_usage();
+ }
# else
+ if (modified_sched_thread_suggested_stack_size) {
erts_fprintf(stderr, "no OS support for dynamic stack size limit\n");
- erts_usage();
-# endif
+ erts_usage();
}
+ /* Be conservative and hope it is not more than 64 kWords... */
+ stacksize = 64*1024*sizeof(void *);
+# endif
+
+ erts_scheduler_stack_limit = erts_calc_stacklimit(&c, stacksize);
}
+
#endif
void
@@ -1293,12 +1312,11 @@ erl_start(int argc, char **argv)
port_tab_sz_ignore_files = 1;
}
-#if (defined(__APPLE__) && defined(__MACH__)) || defined(__DARWIN__)
/*
- * The default stack size on MacOS X is too small for pcre.
+ * A default stack size suitable for pcre which might use quite
+ * a lot of stack.
*/
- erts_sched_thread_suggested_stack_size = 256;
-#endif
+ erts_sched_thread_suggested_stack_size = ERTS_DEFAULT_SCHED_STACK_SIZE;
#ifdef DEBUG
verbose = DEBUG_DEFAULT;
@@ -1921,6 +1939,7 @@ erl_start(int argc, char **argv)
/* suggested stack size (Kilo Words) for scheduler threads */
arg = get_arg(sub_param+2, argv[i+1], &i);
erts_sched_thread_suggested_stack_size = atoi(arg);
+ modified_sched_thread_suggested_stack_size = 1;
if ((erts_sched_thread_suggested_stack_size
< ERTS_SCHED_THREAD_MIN_STACK_SIZE)
@@ -2230,6 +2249,9 @@ erl_start(int argc, char **argv)
boot_argc = argc - i; /* Number of arguments to init */
boot_argv = &argv[i];
+ if (erts_sched_thread_suggested_stack_size < ERTS_MIN_SCHED_STACK_SIZE)
+ erts_sched_thread_suggested_stack_size = ERTS_MIN_SCHED_STACK_SIZE;
+
erl_init(ncpu,
proc_tab_sz,
legacy_proc_tab,
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 19286e1310..45c01673d8 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1218,6 +1218,11 @@ void erts_short_init(void);
void erl_start(int, char**);
void erts_usage(void);
Eterm erts_preloaded(Process* p);
+
+#ifndef ERTS_SMP
+extern void *erts_scheduler_stack_limit;
+#endif
+
/* erl_md5.c */
typedef struct {
@@ -1278,6 +1283,11 @@ Uint64 erts_timestamp_millis(void);
Export* erts_find_function(Eterm, Eterm, unsigned int, ErtsCodeIndex);
+void *erts_calc_stacklimit(char *prev_c, UWord stacksize);
+int erts_check_below_limit(char *ptr, char *limit);
+int erts_check_above_limit(char *ptr, char *limit);
+void *erts_ptr_id(void *ptr);
+
Eterm store_external_or_ref_in_proc_(Process *, Eterm);
Eterm store_external_or_ref_(Uint **, ErlOffHeap*, Eterm);
@@ -1313,6 +1323,11 @@ void erts_init_external(void);
/* erl_map.c */
void erts_init_map(void);
+/* beam_debug.c */
+UWord erts_check_stack_recursion_downwards(char *start_c);
+UWord erts_check_stack_recursion_upwards(char *start_c);
+int erts_is_above_stack_limit(char *ptr);
+
/* erl_unicode.c */
void erts_init_unicode(void);
Sint erts_unicode_set_loop_limit(Sint limit);
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index d49edad6dc..41ba51d037 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -604,6 +604,8 @@ __decl_noreturn void __noreturn erts_exit(int n, char*, ...);
Eterm erts_check_io_info(void *p);
+UWord erts_sys_get_page_size(void);
+
/* Size of misc memory allocated from system dependent code */
Uint erts_sys_misc_mem_sz(void);
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index d90c282c7e..d91ae1ffe6 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -5031,6 +5031,53 @@ Uint64 erts_timestamp_millis(void)
#endif
}
+void *
+erts_calc_stacklimit(char *prev_c, UWord stacksize)
+{
+ /*
+ * We *don't* want this function inlined, i.e., it is
+ * risky to call this function from another function
+ * in utils.c
+ */
+
+ UWord pagesize = erts_sys_get_page_size();
+ char c;
+ char *start;
+ if (&c > prev_c) {
+ start = (char *) ((((UWord) prev_c) / pagesize) * pagesize);
+ return (void *) (start + stacksize);
+ }
+ else {
+ start = (char *) (((((UWord) prev_c) - 1) / pagesize + 1) * pagesize);
+ return (void *) (start - stacksize);
+ }
+}
+
+/*
+ * erts_check_below_limit() and
+ * erts_check_above_limit() are put
+ * in utils.c in order to prevent
+ * inlining.
+ */
+
+int
+erts_check_below_limit(char *ptr, char *limit)
+{
+ return ptr < limit;
+}
+
+int
+erts_check_above_limit(char *ptr, char *limit)
+{
+ return ptr > limit;
+}
+
+void *
+erts_ptr_id(void *ptr)
+{
+ return ptr;
+}
+
#ifdef DEBUG
/*
* Handy functions when using a debugger - don't use in the code!