[binutils-gdb] [gdb] Fix assertion failure due to null frame
Tom de Vries
vries@sourceware.org
Sat Oct 4 00:07:18 GMT 2025
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=32a7293a027d1bf7690d428075e52aa97dbf8350
commit 32a7293a027d1bf7690d428075e52aa97dbf8350
Author: Tom de Vries <tdevries@suse.de>
Date: Sat Oct 4 02:07:16 2025 +0200
[gdb] Fix assertion failure due to null frame
PR gdb/33512 reports an assertion failure in test-case
gdb.ada/access_to_packed_array.exp on i386-linux:
...
(gdb) maint print symbols
gdb/frame.c:3400: internal-error: reinflate: \
Assertion `m_cached_level >= -1' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: $exp: \
maint print symbols (GDB internal error)
...
I haven't been able to reproduce the failure by running the test-case on
x86_64-linux with target board unix/-m32, but I'm able to reproduce on
x86_64-linux by using the exec attached to the PR:
...
$ cat gdb.in
file foo
maint expand-symtabs
maint print symbols
$ gdb -q -batch -ex "set trace-commands on" -x gdb.in
...
c_to: array (gdb/frame.c:3395: internal-error: reinflate: \
Assertion `m_cached_level >= -1' failed.
...
The problem happens when trying to print variable c_to:
...
<4><f227>: Abbrev Number: 3 (DW_TAG_variable)
<f228> DW_AT_name : c_to
<f230> DW_AT_type : <0xf214>
...
with type:
...
<4><f214>: Abbrev Number: 7 (DW_TAG_array_type)
<f215> DW_AT_type : <0x9f39>
<5><f21d>: Abbrev Number: 12 (DW_TAG_subrange_type)
<f21e> DW_AT_type : <0x9d6c>
<f222> DW_AT_upper_bound : <0xf209>
...
with upper bound:
...
<4><f209>: Abbrev Number: 89 (DW_TAG_variable)
<f20a> DW_AT_name : system__os_lib__copy_file__copy_to__TTc_toSP1___U
<f20e> DW_AT_type : <0x9d6c>
<f212> DW_AT_artificial : 1
<f212> DW_AT_location : 1 byte block: 57 (DW_OP_reg7 (edi))
...
The backtrace at the point of the assertion failure is:
...
(gdb) bt
#0 __pthread_kill_implementation (threadid=<optimized out>,
signo=signo@entry=6, no_tid=no_tid@entry=0) at pthread_kill.c:44
#1 0x00007ffff62a8e7f in __pthread_kill_internal (signo=6,
threadid=<optimized out>) at pthread_kill.c:78
#2 0x00007ffff6257842 in __GI_raise (sig=sig@entry=6)
at ../sysdeps/posix/raise.c:26
#3 0x00007ffff623f5cf in __GI_abort () at abort.c:79
#4 0x00000000010e7ac6 in dump_core () at gdb/utils.c:223
#5 0x00000000010e81b8 in internal_vproblem(internal_problem *, const char *, int, const char *, typedef __va_list_tag __va_list_tag *) (
problem=0x2ceb0c0 <internal_error_problem>,
file=0x1ad5a90 "gdb/frame.c", line=3395,
fmt=0x1ad5a08 "%s: Assertion `%s' failed.", ap=0x7fffffffc3c0)
at gdb/utils.c:475
#6 0x00000000010e82ac in internal_verror (
file=0x1ad5a90 "gdb/frame.c", line=3395,
fmt=0x1ad5a08 "%s: Assertion `%s' failed.", ap=0x7fffffffc3c0)
at gdb/utils.c:501
#7 0x00000000019be79f in internal_error_loc (
file=0x1ad5a90 "gdb/frame.c", line=3395,
fmt=0x1ad5a08 "%s: Assertion `%s' failed.")
at gdbsupport/errors.cc:57
#8 0x00000000009b5c16 in frame_info_ptr::reinflate (this=0x7fffffffc878)
at gdb/frame.c:3395
#9 0x00000000009b66f9 in frame_info_ptr::operator-> (this=0x7fffffffc878)
at gdb/frame.h:290
#10 0x00000000009b4bd5 in get_frame_arch (this_frame=...)
at gdb/frame.c:3075
#11 0x000000000081dd89 in dwarf_expr_context::fetch_result (
this=0x7fffffffc810, type=0x410d600, subobj_type=0x410d600,
subobj_offset=0, as_lval=true)
at gdb/dwarf2/expr.c:1006
#12 0x000000000081e2ef in dwarf_expr_context::evaluate (this=0x7fffffffc810,
addr=0x7ffff459ce6b "W\aF\003", len=1, as_lval=true,
per_cu=0x7fffd00053f0, frame=..., addr_info=0x7fffffffcc30, type=0x0,
subobj_type=0x0, subobj_offset=0)
at gdb/dwarf2/expr.c:1136
#13 0x0000000000877c14 in dwarf2_locexpr_baton_eval (dlbaton=0x3e99c18,
frame=..., addr_stack=0x7fffffffcc30, valp=0x7fffffffcab0,
push_values=..., is_reference=0x7fffffffc9b0)
at gdb/dwarf2/loc.c:1604
#14 0x0000000000877f71 in dwarf2_evaluate_property (prop=0x3e99ce0,
initial_frame=..., addr_stack=0x7fffffffcc30, value=0x7fffffffcab0,
push_values=...) at gdb/dwarf2/loc.c:1668
#15 0x00000000009def76 in resolve_dynamic_range (dyn_range_type=0x3e99c50,
addr_stack=0x7fffffffcc30, frame=..., rank=0, resolve_p=true)
at gdb/gdbtypes.c:2198
#16 0x00000000009e0ded in resolve_dynamic_type_internal (type=0x3e99c50,
addr_stack=0x7fffffffcc30, frame=..., top_level=true)
at gdb/gdbtypes.c:2934
#17 0x00000000009e1079 in resolve_dynamic_type (type=0x3e99c50, valaddr=...,
addr=0, in_frame=0x0) at gdb/gdbtypes.c:2989
#18 0x0000000000488ebc in ada_discrete_type_low_bound (type=0x3e99c50)
at gdb/ada-lang.c:710
#19 0x00000000004eb734 in print_range (type=0x3e99c50, stream=0x30157b0,
bounds_preferred_p=0) at gdb/ada-typeprint.c:156
#20 0x00000000004ebffe in print_array_type (type=0x3e99d10, stream=0x30157b0,
show=1, level=9, flags=0x1bdcf20 <type_print_raw_options>)
at gdb/ada-typeprint.c:381
#21 0x00000000004eda3c in ada_print_type (type0=0x3e99d10,
varstring=0x401f710 "c_to", stream=0x30157b0, show=1, level=9,
flags=0x1bdcf20 <type_print_raw_options>)
at gdb/ada-typeprint.c:1015
#22 0x00000000004b4627 in ada_language::print_type (
this=0x2f949b0 <ada_language_defn>, type=0x3e99d10,
varstring=0x401f710 "c_to", stream=0x30157b0, show=1, level=9,
flags=0x1bdcf20 <type_print_raw_options>)
at gdb/ada-lang.c:13681
#23 0x0000000000f74646 in print_symbol (gdbarch=0x3256270, symbol=0x3e99db0,
depth=9, outfile=0x30157b0) at gdb/symmisc.c:545
#24 0x0000000000f737e6 in dump_symtab_1 (symtab=0x3ddd7e0, outfile=0x30157b0)
at gdb/symmisc.c:313
#25 0x0000000000f73a69 in dump_symtab (symtab=0x3ddd7e0, outfile=0x30157b0)
at gdb/symmisc.c:370
#26 0x0000000000f7420f in maintenance_print_symbols (args=0x0, from_tty=0)
at gdb/symmisc.c:481
#27 0x00000000006c7fde in do_simple_func (args=0x0, from_tty=0, c=0x321e270)
at gdb/cli/cli-decode.c:94
#28 0x00000000006ce65a in cmd_func (cmd=0x321e270, args=0x0, from_tty=0)
at gdb/cli/cli-decode.c:2826
#29 0x0000000001005b78 in execute_command (p=0x3f48fe3 "", from_tty=0)
at gdb/top.c:564
#30 0x0000000000966095 in command_handler (
command=0x3f48fd0 "maint print symbols")
at gdb/event-top.c:613
#31 0x0000000001005141 in read_command_file (stream=0x3011a40)
at gdb/top.c:333
#32 0x00000000006e2a64 in script_from_file (stream=0x3011a40,
file=0x7fffffffe21f "gdb.in")
at gdb/cli/cli-script.c:1705
#33 0x00000000006bb88c in source_script_from_stream (stream=0x3011a40,
file=0x7fffffffe21f "gdb.in", file_to_open=0x7fffffffd760 "gdb.in")
at gdb/cli/cli-cmds.c:706
#34 0x00000000006bba12 in source_script_with_search (
file=0x7fffffffe21f "gdb.in", from_tty=0, search_path=0)
at gdb/cli/cli-cmds.c:751
#35 0x00000000006bbab2 in source_script (file=0x7fffffffe21f "gdb.in",
from_tty=0) at gdb/cli/cli-cmds.c:760
#36 0x0000000000b835cb in catch_command_errors (
command=0x6bba7e <source_script(char const*, int)>,
arg=0x7fffffffe21f "gdb.in", from_tty=0, do_bp_actions=false)
at gdb/main.c:510
#37 0x0000000000b83803 in execute_cmdargs (cmdarg_vec=0x7fffffffd980,
file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND, ret=0x7fffffffd8c8)
at gdb/main.c:606
#38 0x0000000000b84d79 in captured_main_1 (context=0x7fffffffdb90)
at gdb/main.c:1349
#39 0x0000000000b84fe4 in captured_main (context=0x7fffffffdb90)
at gdb/main.c:1372
#40 0x0000000000b85092 in gdb_main (args=0x7fffffffdb90)
at gdb/main.c:1401
#41 0x000000000041a382 in main (argc=9, argv=0x7fffffffdcc8)
at gdb/gdb.c:38
(gdb)
...
The immediate problem is in dwarf_expr_context::fetch_result where we're
calling get_frame_arch:
...
switch (this->m_location)
{
case DWARF_VALUE_REGISTER:
{
gdbarch *f_arch = get_frame_arch (this->m_frame);
...
with a null frame:
...
(gdb) p this->m_frame.is_null ()
$1 = true
(gdb)
...
Fix this using ensure_have_frame in dwarf_expr_context::execute_stack_op for
DW_OP_reg<n> and DW_OP_regx, getting us instead:
...
c_to: array (<>) of character; computed at runtime
...
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33512
Diff:
---
gdb/dwarf2/expr.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/gdb/dwarf2/expr.c b/gdb/dwarf2/expr.c
index 346bf7ffab6..aa2fd9d6652 100644
--- a/gdb/dwarf2/expr.c
+++ b/gdb/dwarf2/expr.c
@@ -1759,6 +1759,10 @@ dwarf_expr_context::execute_stack_op (const gdb_byte *op_ptr,
case DW_OP_reg29:
case DW_OP_reg30:
case DW_OP_reg31:
+ /* The value of a register is relative to a frame, so we require a
+ valid frame. */
+ ensure_have_frame (this->m_frame, "DW_OP_reg<n>");
+
dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_reg");
result = op - DW_OP_reg0;
@@ -1767,6 +1771,10 @@ dwarf_expr_context::execute_stack_op (const gdb_byte *op_ptr,
break;
case DW_OP_regx:
+ /* The value of a register is relative to a frame, so we require a
+ valid frame. */
+ ensure_have_frame (this->m_frame, "DW_OP_regx");
+
op_ptr = safe_read_uleb128 (op_ptr, op_end, ®);
dwarf_expr_require_composition (op_ptr, op_end, "DW_OP_regx");
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