From: Craig Blackmore Date: Thu, 13 Feb 2025 15:53:34 +0000 (+0000) Subject: gdb: Fix assertion failure when inline frame #0 is duplicated X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fbd747b6a406beff96cc1d3767165aa3f5514a60;p=thirdparty%2Fbinutils-gdb.git gdb: Fix assertion failure when inline frame #0 is duplicated Modifying inline-frame-cycle-unwind.exp to use `bt -no-filters` produces the following incorrect backtrace: #0 inline_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:49 #1 normal_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:32 #2 0x000055555555517f in inline_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:50 #3 normal_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:32 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) FAIL: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 1: backtrace when the unwind is broken at frame 1 The expected output, which we get with `bt`, is: #0 inline_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:49 #1 normal_func () at .../gdb/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.c:32 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) PASS: gdb.base/inline-frame-cycle-unwind.exp: cycle at level 1: backtrace when the unwind is broken at frame 1 The cycle checking in `get_prev_frame_maybe_check_cycle` relies on newer frame ids having already been computed and stashed. Unlike other frames, frame #0's id does not get computed immediately. The test passes with `bt` because when applying python frame filters, the call to `bootstrap_python_frame_filters` happens to compute the id of frame #0. When `get_prev_frame_maybe_check_cycle` later tries to stash frame #2's id, the cycle is detected. The test fails with `bt -no-filters` because frame #0's id has not been stashed by the time `get_prev_frame_maybe_check_cycle` tries to stash frame #2's id which succeeds and the cycle is only detected later when trying to stash frame #4's id. Doing `stepi` after the incorrect backtrace would then trigger an assertion failure when trying to stash frame #0's id because it is a duplicate of #2's already stashed id. In `get_prev_frame_always_1`, if this_frame is inline frame 0, then compute and stash its frame id before returning the previous frame. This ensures that the id of inline frame 0 has been stashed before `get_prev_frame_maybe_check_cycle` is called on older frames. The test case has been updated to run both `bt` and `bt -no-filters`. Co-authored-by: Andrew Burgess --- diff --git a/gdb/frame.c b/gdb/frame.c index 2fb06a004f0..88560b8d905 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -2325,7 +2325,22 @@ get_prev_frame_always_1 (const frame_info_ptr &this_frame) until we have unwound all the way down to the previous non-inline frame. */ if (get_frame_type (this_frame) == INLINE_FRAME) - return get_prev_frame_maybe_check_cycle (this_frame); + { + frame_info_ptr fi = get_prev_frame_maybe_check_cycle (this_frame); + + /* If this_frame is the current frame, then compute and stash its frame + id so that the cycle check in get_prev_frame_maybe_check_cycle works + correctly in the case where inline frame 0 has been duplicated. + + The this_id.p check is required to avoid recursion as computing the + frame id results in a call to inline_frame_this_id which calls back + into get_prev_frame_always. */ + if (this_frame->level == 0 + && this_frame->this_id.p != frame_id_status::COMPUTING) + get_frame_id (this_frame); + + return fi; + } /* If this_frame is the current frame, then compute and stash its frame id prior to fetching and computing the frame id of the diff --git a/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.exp b/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.exp index 45086f69a39..46561a9c9fb 100644 --- a/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.exp +++ b/gdb/testsuite/gdb.base/inline-frame-cycle-unwind.exp @@ -72,77 +72,89 @@ gdb_continue_to_breakpoint "stop at test breakpoint" gdb_test_no_output "source ${pyfile}"\ "import python scripts" -# Check the unbroken stack. -gdb_test_sequence "bt" "backtrace when the unwind is left unbroken" { - "\\r\\n#0 \[^\r\n\]* inline_func \\(\\) at " - "\\r\\n#1 \[^\r\n\]* normal_func \\(\\) at " - "\\r\\n#2 \[^\r\n\]* inline_func \\(\\) at " - "\\r\\n#3 \[^\r\n\]* normal_func \\(\\) at " - "\\r\\n#4 \[^\r\n\]* inline_func \\(\\) at " - "\\r\\n#5 \[^\r\n\]* normal_func \\(\\) at " - "\\r\\n#6 \[^\r\n\]* main \\(\\) at " -} +# Test with and without filters. +foreach bt_cmd { "bt" "bt -no-filters" } { + with_test_prefix "$bt_cmd" { -with_test_prefix "cycle at level 5" { - # Arrange to introduce a stack cycle at frame 5. - gdb_test_no_output "python stop_at_level=5" - gdb_test "maint flush register-cache" \ - "Register cache flushed\\." - gdb_test_lines "bt" "backtrace when the unwind is broken at frame 5" \ - [multi_line \ - "#0 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ - "#1 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ - "#2 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ - "#3 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ - "#4 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ - "#5 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ - "Backtrace stopped: previous frame identical to this frame \\(corrupt stack\\?\\)"] -} + # Check the unbroken stack. + gdb_test_sequence "$bt_cmd" "backtrace when the unwind is left unbroken" { + "\\r\\n#0 \[^\r\n\]* inline_func \\(\\) at " + "\\r\\n#1 \[^\r\n\]* normal_func \\(\\) at " + "\\r\\n#2 \[^\r\n\]* inline_func \\(\\) at " + "\\r\\n#3 \[^\r\n\]* normal_func \\(\\) at " + "\\r\\n#4 \[^\r\n\]* inline_func \\(\\) at " + "\\r\\n#5 \[^\r\n\]* normal_func \\(\\) at " + "\\r\\n#6 \[^\r\n\]* main \\(\\) at " + } -with_test_prefix "cycle at level 3" { - # Arrange to introduce a stack cycle at frame 3. - gdb_test_no_output "python stop_at_level=3" - gdb_test "maint flush register-cache" \ - "Register cache flushed\\." - gdb_test_lines "bt" "backtrace when the unwind is broken at frame 3" \ - [multi_line \ - "#0 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ - "#1 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ - "#2 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ - "#3 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ - "Backtrace stopped: previous frame identical to this frame \\(corrupt stack\\?\\)"] -} + with_test_prefix "cycle at level 5" { + # Arrange to introduce a stack cycle at frame 5. + gdb_test_no_output "python stop_at_level=5" + gdb_test "maint flush register-cache" \ + "Register cache flushed\\." + gdb_test_lines "$bt_cmd" "backtrace when the unwind is broken at frame 5" \ + [multi_line \ + "#0 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ + "#1 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ + "#2 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ + "#3 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ + "#4 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ + "#5 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ + "Backtrace stopped: previous frame identical to this frame \\(corrupt stack\\?\\)"] + } -with_test_prefix "cycle at level 1" { - # Arrange to introduce a stack cycle at frame 1. - gdb_test_no_output "python stop_at_level=1" - gdb_test "maint flush register-cache" \ - "Register cache flushed\\." - gdb_test_lines "bt" "backtrace when the unwind is broken at frame 1" \ - [multi_line \ - "#0 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ - "#1 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ - "Backtrace stopped: previous frame identical to this frame \\(corrupt stack\\?\\)"] -} + with_test_prefix "cycle at level 3" { + # Arrange to introduce a stack cycle at frame 3. + gdb_test_no_output "python stop_at_level=3" + gdb_test "maint flush register-cache" \ + "Register cache flushed\\." + gdb_test_lines "$bt_cmd" "backtrace when the unwind is broken at frame 3" \ + [multi_line \ + "#0 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ + "#1 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ + "#2 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ + "#3 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ + "Backtrace stopped: previous frame identical to this frame \\(corrupt stack\\?\\)"] + } -# Flush the register cache (which also flushes the frame cache) so we -# get a full backtrace again, then switch on frame debugging and try -# to back trace. At one point this triggered an assertion. -gdb_test "maint flush register-cache" \ - "Register cache flushed\\." "" -gdb_test_no_output "set debug frame 1" -set ok 1 -gdb_test_multiple "bt" "backtrace with debugging on" { - -re "^$gdb_prompt $" { - gdb_assert { $ok } $gdb_test_name - } - -re "Python Exception : \[^\r\n\]*\r\n" { - set ok 0 - exp_continue - } - -re "\[^\r\n\]+\r\n" { - exp_continue + with_test_prefix "cycle at level 1" { + # Arrange to introduce a stack cycle at frame 1. + gdb_test_no_output "python stop_at_level=1" + gdb_test "maint flush register-cache" \ + "Register cache flushed\\." + gdb_test_lines "$bt_cmd" "backtrace when the unwind is broken at frame 1" \ + [multi_line \ + "#0 \[^\r\n\]* inline_func \\(\\) at \[^\r\n\]+" \ + "#1 \[^\r\n\]* normal_func \\(\\) at \[^\r\n\]+" \ + "Backtrace stopped: previous frame identical to this frame \\(corrupt stack\\?\\)"] + } + + # Flush the register cache (which also flushes the frame cache) so we + # get a full backtrace again, then switch on frame debugging and try + # to back trace. At one point this triggered an assertion. + gdb_test "maint flush register-cache" \ + "Register cache flushed\\." "" + gdb_test_no_output "set debug frame 1" + set ok 1 + gdb_test_multiple "$bt_cmd" "backtrace with debugging on" { + -re "^$gdb_prompt $" { + gdb_assert { $ok } $gdb_test_name + } + -re "Python Exception : \[^\r\n\]*\r\n" { + set ok 0 + exp_continue + } + -re "\[^\r\n\]+\r\n" { + exp_continue + } + } + gdb_test "p 1 + 2 + 3" " = 6" \ + "ensure GDB is still alive" + + # Prepare for the next iteration of the test loop + gdb_test_no_output "set debug frame 0" + gdb_test_no_output "python stop_at_level=None" + gdb_test "maint flush register-cache" \ + "Register cache flushed\\." "maint flush register-cache at (loop end)" } } -gdb_test "p 1 + 2 + 3" " = 6" \ - "ensure GDB is still alive"