http://sourceware.org/ml/gdb-patches/2012-07/msg00197.html Subject: [patch] Fix another stale frame_info * (PR 11914, like PR 13866) Hi, http://sourceware.org/bugzilla/show_bug.cgi?id=11914 has another case of stale frame_info *. Originally I found it unfixable with the current struct frame_info * usage but Pedro has shown in PR 13866 it is possible to fix the cases one by one so I have fixed also this one. It follows the path of valgrind backtrace showing where the memory is being freed: http://sourceware.org/bugzilla/show_bug.cgi?id=11914#c5 This message has been already present in GDB so I used it in more cases: + warning (_("Unable to restore previously selected frame.")); No regressions on {x86_64,x86_64-m32,i686}-fedorarawhide-linux-gnu. I will check it in soon for 7.5. I find it a bit difficult to reliably reproduce, this testcases mostly always crashes for me (at least with -lmcheck). Thanks, Jan gdb/ 2012-07-14 Jan Kratochvil PR 11914 * f-valprint.c (info_common_command): New variable frame_id. Reinitialize FI form FRAME_ID after each print_variable_and_value. * printcmd.c (print_variable_and_value): Extend function comment. Add comment for invalidated FRAME. * stack.c (backtrace_command_1): New variable frame_id. Reinitialize FI form FRAME_ID after each print_frame_local_vars. (struct print_variable_and_value_data): Change frame to frame_id. (do_print_variable_and_value): New variable frame, initialize it from p->frame_id. Add comment for invalidated FRAME. (print_frame_local_vars, print_frame_arg_vars): New function comment. Update CB_DATA.FRAME to CB_DATA.FRAME_ID initialization. Add comment for invalidated FRAME. gdb/testsuite/ 2012-07-14 Jan Kratochvil PR 11914 * gdb.python/py-prettyprint.c (eval_func, eval_sub): New. (main): Call eval_sub. * gdb.python/py-prettyprint.exp: (python execfile ('py-prettyprint.py')): Move it earlier. New breakpoint for eval-break. (continue to breakpoint: eval-break, info locals): New test. (python execfile ('py-prettyprint.py')): Move it from here. * gdb.python/py-prettyprint.py (class pp_eval_type): New. (register_pretty_printers): Register pp_eval_type. diff --git a/gdb/printcmd.c b/gdb/printcmd.c index 2a0a886..d5b5b63 100644 --- a/gdb/printcmd.c +++ b/gdb/printcmd.c @@ -1961,7 +1961,9 @@ clear_dangling_display_expressions (struct so_list *solib) struct symbol. NAME is the name to print; if NULL then VAR's print name will be used. STREAM is the ui_file on which to print the value. INDENT specifies the number of indent levels to print - before printing the variable name. */ + before printing the variable name. + + This function invalidates FRAME. */ void print_variable_and_value (const char *name, struct symbol *var, @@ -1983,6 +1985,10 @@ print_variable_and_value (const char *name, struct symbol *var, get_user_print_options (&opts); opts.deref_ref = 1; common_val_print (val, stream, indent, &opts, current_language); + + /* common_val_print invalidates FRAME when a pretty printer calls inferior + function. */ + frame = NULL; } if (except.reason < 0) fprintf_filtered(stream, "", name, diff --git a/gdb/stack.c b/gdb/stack.c index 2520e2c..35d379d 100644 --- a/gdb/stack.c +++ b/gdb/stack.c @@ -1727,7 +1727,20 @@ backtrace_command_1 (char *count_exp, int show_locals, int from_tty) the frame->prev field gets set to NULL in that case). */ print_frame_info (fi, 1, LOCATION, 1); if (show_locals) - print_frame_local_vars (fi, 1, gdb_stdout); + { + struct frame_id frame_id = get_frame_id (fi); + + print_frame_local_vars (fi, 1, gdb_stdout); + + /* print_frame_local_vars invalidates FI. */ + fi = frame_find_by_id (frame_id); + if (fi == NULL) + { + trailing = NULL; + warning (_("Unable to restore previously selected frame.")); + break; + } + } /* Save the last frame to check for error conditions. */ trailing = fi; @@ -1919,7 +1932,7 @@ iterate_over_block_local_vars (struct block *block, struct print_variable_and_value_data { - struct frame_info *frame; + struct frame_id frame_id; int num_tabs; struct ui_file *stream; int values_printed; @@ -1933,12 +1946,28 @@ do_print_variable_and_value (const char *print_name, void *cb_data) { struct print_variable_and_value_data *p = cb_data; + struct frame_info *frame; + + frame = frame_find_by_id (p->frame_id); + if (frame == NULL) + { + warning (_("Unable to restore previously selected frame.")); + return; + } + + print_variable_and_value (print_name, sym, frame, p->stream, p->num_tabs); + + /* print_variable_and_value invalidates FRAME. */ + frame = NULL; - print_variable_and_value (print_name, sym, - p->frame, p->stream, p->num_tabs); p->values_printed = 1; } +/* Print all variables from the innermost up to the function block of FRAME. + Print them with values to STREAM indented by NUM_TABS. + + This function will invalidate FRAME. */ + static void print_frame_local_vars (struct frame_info *frame, int num_tabs, struct ui_file *stream) @@ -1961,7 +1990,7 @@ print_frame_local_vars (struct frame_info *frame, int num_tabs, return; } - cb_data.frame = frame; + cb_data.frame_id = get_frame_id (frame); cb_data.num_tabs = 4 * num_tabs; cb_data.stream = stream; cb_data.values_printed = 0; @@ -1970,6 +1999,9 @@ print_frame_local_vars (struct frame_info *frame, int num_tabs, do_print_variable_and_value, &cb_data); + /* do_print_variable_and_value invalidates FRAME. */ + frame = NULL; + if (!cb_data.values_printed) fprintf_filtered (stream, _("No locals.\n")); } @@ -2016,6 +2048,11 @@ iterate_over_block_arg_vars (struct block *b, } } +/* Print all argument variables of the function of FRAME. + Print them with values to STREAM. + + This function will invalidate FRAME. */ + static void print_frame_arg_vars (struct frame_info *frame, struct ui_file *stream) { @@ -2036,7 +2073,7 @@ print_frame_arg_vars (struct frame_info *frame, struct ui_file *stream) return; } - cb_data.frame = frame; + cb_data.frame_id = get_frame_id (frame); cb_data.num_tabs = 0; cb_data.stream = gdb_stdout; cb_data.values_printed = 0; @@ -2044,6 +2081,9 @@ print_frame_arg_vars (struct frame_info *frame, struct ui_file *stream) iterate_over_block_arg_vars (SYMBOL_BLOCK_VALUE (func), do_print_variable_and_value, &cb_data); + /* do_print_variable_and_value invalidates FRAME. */ + frame = NULL; + if (!cb_data.values_printed) fprintf_filtered (stream, _("No arguments.\n")); } diff --git a/gdb/testsuite/gdb.python/py-prettyprint.c b/gdb/testsuite/gdb.python/py-prettyprint.c index 0ff7b33..1ff9e05 100644 --- a/gdb/testsuite/gdb.python/py-prettyprint.c +++ b/gdb/testsuite/gdb.python/py-prettyprint.c @@ -219,6 +219,22 @@ struct nullstr struct string_repr string_1 = { { "one" } }; struct string_repr string_2 = { { "two" } }; +static int +eval_func (int p1, int p2, int p3, int p4, int p5, int p6, int p7, int p8) +{ + return p1; +} + +static void +eval_sub (void) +{ + struct eval_type_s { int x; } eval1 = { 1 }, eval2 = { 2 }, eval3 = { 3 }, + eval4 = { 4 }, eval5 = { 5 }, eval6 = { 6 }, + eval7 = { 7 }, eval8 = { 8 }, eval9 = { 9 }; + + eval1.x++; /* eval-break */ +} + int main () { @@ -309,5 +325,7 @@ main () nstype2 = nstype; + eval_sub (); + return 0; /* break to inspect struct and union */ } diff --git a/gdb/testsuite/gdb.python/py-prettyprint.exp b/gdb/testsuite/gdb.python/py-prettyprint.exp index a6c241a..22af83c 100644 --- a/gdb/testsuite/gdb.python/py-prettyprint.exp +++ b/gdb/testsuite/gdb.python/py-prettyprint.exp @@ -123,14 +123,19 @@ if ![runto_main ] then { return } -gdb_test "b [gdb_get_line_number {break to inspect} ${testfile}.c ]" \ - ".*Breakpoint.*" -gdb_test "continue" ".*Breakpoint.*" - set remote_python_file [remote_download host ${srcdir}/${subdir}/${testfile}.py] gdb_test_no_output "python execfile ('${remote_python_file}')" +gdb_breakpoint [gdb_get_line_number "eval-break"] +gdb_continue_to_breakpoint "eval-break" ".* eval-break .*" + +gdb_test "info locals" "eval9 = eval=<123456789>" + +gdb_test "b [gdb_get_line_number {break to inspect} ${testfile}.c ]" \ + ".*Breakpoint.*" +gdb_test "continue" ".*Breakpoint.*" + gdb_test "print ss" " = a=< a=<1> b=<$hex>> b=< a=<2> b=<$hex>>" \ "print ss enabled #1" diff --git a/gdb/testsuite/gdb.python/py-prettyprint.py b/gdb/testsuite/gdb.python/py-prettyprint.py index 52ffd1a..b02b90f 100644 --- a/gdb/testsuite/gdb.python/py-prettyprint.py +++ b/gdb/testsuite/gdb.python/py-prettyprint.py @@ -199,6 +199,14 @@ class MemoryErrorString: def display_hint (self): return 'string' +class pp_eval_type: + def __init__(self, val): + self.val = val + + def to_string(self): + gdb.execute("bt", to_string=True) + return "eval=<" + str(gdb.parse_and_eval("eval_func (123456789, 2, 3, 4, 5, 6, 7, 8)")) + ">" + def lookup_function (val): "Look-up and return a pretty-printer that can print val." @@ -276,6 +284,8 @@ def register_pretty_printers (): pretty_printers_dict[re.compile ('^memory_error$')] = MemoryErrorString + pretty_printers_dict[re.compile ('^eval_type_s$')] = pp_eval_type + pretty_printers_dict = {} register_pretty_printers ()