Remove previous frame if an error occurs when computing frame id during unwind.
https://sourceware.org/ml/gdb-patches/2014-05/msg00712.html If an error is thrown during computing a frame id then the frame is left in existence but without a valid frame id, this will trigger internal errors if/when the frame is later visited (for example in a backtrace). This patch catches errors raised while computing the frame id, and arranges for the new frame, the one without a frame id, to be removed from the linked list of frames. gdb/ChangeLog: * frame.c (remove_prev_frame): New function. (get_prev_frame_if_no_cycle): Create / discard cleanup using remove_prev_frame. gdb/testsuite/ChangeLog: * gdb.arch/amd64-invalid-stack-middle.S: New file. * gdb.arch/amd64-invalid-stack-middle.c: New file. * gdb.arch/amd64-invalid-stack-middle.exp: New file. * gdb.arch/amd64-invalid-stack-top.c: New file. * gdb.arch/amd64-invalid-stack-top.exp: New file.
This commit is contained in:
Andrew Burgess
parent
f6fb832249
commit
938f0e2f67
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@ -1,3 +1,9 @@
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2014-05-30 Andrew Burgess <aburgess@broadcom.com>
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* frame.c (remove_prev_frame): New function.
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(get_prev_frame_if_no_cycle): Create / discard cleanup using
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remove_prev_frame.
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2014-05-29 Pedro Alves <palves@redhat.com>
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* infrun.c (resume): Rename local 'hw_step' to 'entry_step'
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52
gdb/frame.c
52
gdb/frame.c
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@ -1738,6 +1738,22 @@ frame_register_unwind_location (struct frame_info *this_frame, int regnum,
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}
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}
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/* Called during frame unwinding to remove a previous frame pointer from a
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frame passed in ARG. */
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static void
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remove_prev_frame (void *arg)
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{
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struct frame_info *this_frame, *prev_frame;
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this_frame = (struct frame_info *) arg;
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prev_frame = this_frame->prev;
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gdb_assert (prev_frame != NULL);
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prev_frame->next = NULL;
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this_frame->prev = NULL;
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}
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/* Get the previous raw frame, and check that it is not identical to
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same other frame frame already in the chain. If it is, there is
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most likely a stack cycle, so we discard it, and mark THIS_FRAME as
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@ -1750,28 +1766,36 @@ static struct frame_info *
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get_prev_frame_if_no_cycle (struct frame_info *this_frame)
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{
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struct frame_info *prev_frame;
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struct cleanup *prev_frame_cleanup;
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prev_frame = get_prev_frame_raw (this_frame);
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if (prev_frame == NULL)
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return NULL;
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compute_frame_id (prev_frame);
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if (frame_stash_add (prev_frame))
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return prev_frame;
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/* The cleanup will remove the previous frame that get_prev_frame_raw
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linked onto THIS_FRAME. */
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prev_frame_cleanup = make_cleanup (remove_prev_frame, this_frame);
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/* Another frame with the same id was already in the stash. We just
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detected a cycle. */
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if (frame_debug)
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compute_frame_id (prev_frame);
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if (!frame_stash_add (prev_frame))
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{
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fprintf_unfiltered (gdb_stdlog, "-> ");
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fprint_frame (gdb_stdlog, NULL);
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fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
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/* Another frame with the same id was already in the stash. We just
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detected a cycle. */
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if (frame_debug)
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{
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fprintf_unfiltered (gdb_stdlog, "-> ");
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fprint_frame (gdb_stdlog, NULL);
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fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
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}
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this_frame->stop_reason = UNWIND_SAME_ID;
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/* Unlink. */
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prev_frame->next = NULL;
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this_frame->prev = NULL;
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prev_frame = NULL;
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}
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this_frame->stop_reason = UNWIND_SAME_ID;
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/* Unlink. */
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prev_frame->next = NULL;
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this_frame->prev = NULL;
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return NULL;
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discard_cleanups (prev_frame_cleanup);
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return prev_frame;
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}
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/* Return a "struct frame_info" corresponding to the frame that called
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@ -1,3 +1,11 @@
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2014-05-30 Andrew Burgess <aburgess@broadcom.com>
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* gdb.arch/amd64-invalid-stack-middle.S: New file.
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* gdb.arch/amd64-invalid-stack-middle.c: New file.
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* gdb.arch/amd64-invalid-stack-middle.exp: New file.
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* gdb.arch/amd64-invalid-stack-top.c: New file.
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* gdb.arch/amd64-invalid-stack-top.exp: New file.
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2014-05-30 Pedro Alves <palves@redhat.com>
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PR breakpoints/17000
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File diff suppressed because it is too large
Load Diff
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@ -0,0 +1,89 @@
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/* This testcase is part of GDB, the GNU debugger.
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Copyright 2014 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <sys/mman.h>
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#include <unistd.h>
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#include <assert.h>
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void
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breakpt (void)
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{
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/* Nothing. */
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}
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void
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func5 (void)
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{
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breakpt ();
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}
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void
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func4 (void)
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{
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func5 ();
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}
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void
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func3 (void)
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{
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func4 ();
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}
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void
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func2 (void *ptr)
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{
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func3 ();
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}
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void
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func1 (void *ptr)
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{
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func2 (ptr);
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}
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/* Finds and returns an invalid pointer, mmaps in a page, grabs a pointer
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to it then unmaps the page again. This is almost certainly "undefined"
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behaviour, but should be good enough for this small test program. */
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static void *
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make_invalid_ptr (void)
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{
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int page_size, ans;
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void *ptr;
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page_size = getpagesize ();
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ptr = mmap (0, page_size, PROT_NONE,
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MAP_PRIVATE | MAP_ANONYMOUS,
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-1, 0);
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assert (ptr != MAP_FAILED);
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ans = munmap (ptr, page_size);
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assert (ans == 0);
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return ptr;
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}
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int
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main (void)
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{
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void *invalid_ptr;
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invalid_ptr = make_invalid_ptr ();
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func1 (invalid_ptr);
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return 0;
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}
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@ -0,0 +1,108 @@
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# Copyright (C) 2014 Free Software Foundation, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# In this test we're looking at how gdb handles backtraces and
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# investigating the stack depth when confronted with an "invalid" stack,
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# that is a stack where the first few frames are normal, and then there's a
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# frame where the stack in unreadable.
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#
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# One interesting bug that has been observed is that gdb will sometime
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# exhibit different behaviour the first time a stack command is run
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# compared to the second (and later) times a command is run. This is
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# because the first time a command is run gdb actually tries to figure out
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# the answer, while the second (and later) times gdb relies on the answer
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# cached from the first time. As a result in this test each command is
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# run twice, and we restart gdb before testing each different command to
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# ensure that nothing is being cached.
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set opts {}
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standard_testfile .S
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if { ![istarget x86_64-*-* ] || ![is_lp64_target] } {
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verbose "Skipping ${testfile}."
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return
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}
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if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} $opts] } {
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return -1
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}
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if ![runto breakpt] {
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return -1
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}
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gdb_test "bt" "^bt\r\n#0 +breakpt *\\(\\) \[^\r\n\]*\r\n#1 +0x\[0-9a-f\]+ in func5\[^\r\n\]*\r\n#2 +0x\[0-9a-f\]+ in func4\[^\r\n\]*\r\n#3 +0x\[0-9a-f\]+ in func3\[^\r\n\]*\r\nCannot access memory at address 0x\[0-9a-f\]+" \
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"first backtrace, with error message"
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send_gdb "bt\n"
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gdb_expect {
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-re "^bt\r\n#0 +breakpt *\\(\\) \[^\r\n\]*\r\n#1 +0x\[0-9a-f\]+ in func5\[^\r\n\]*\r\n#2 +0x\[0-9a-f\]+ in func4\[^\r\n\]*\r\n#3 +0x\[0-9a-f\]+ in func3\[^\r\n\]*\r\nCannot access memory at address 0x\[0-9a-f\]+\r\n$gdb_prompt $" {
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# Currently gdb will not display the error message associated with
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# the truncated backtrace after the first backtrace has been
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# completed. Ideally, we would do this. If this case is ever hit
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# then we have started to display the backtrace in all cases and
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# the xpass should becomd a pass, and the previous pass case below
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# should be removed, or changed to a fail.
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xpass "second backtrace, with error message"
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}
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-re "^bt\r\n#0 +breakpt *\\(\\) \[^\r\n\]*\r\n#1 +0x\[0-9a-f\]+ in func5\[^\r\n\]*\r\n#2 +0x\[0-9a-f\]+ in func4\[^\r\n\]*\r\n#3 +0x\[0-9a-f\]+ in func3\[^\r\n\]*\r\n$gdb_prompt $" {
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pass "second backtrace, without error message"
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}
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timeout {
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fail "second backtrace (timeout)"
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}
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}
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clean_restart ${binfile}
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if ![runto breakpt] {
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return -1
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}
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set test_name "check mi -stack-info-depth command, first time"
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send_gdb "interpreter-exec mi \"-stack-info-depth\"\n"
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gdb_expect {
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-re "\\^done,depth=\"4\"\r\n$gdb_prompt $" {
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pass $test_name
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}
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-re "\\^error,msg=\"Cannot access memory at address $hex\"\r\n$gdb_prompt $" {
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xfail $test_name
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}
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}
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gdb_test "interpreter-exec mi \"-stack-info-depth\"" \
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"\\^done,depth=\"4\"" \
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"check mi -stack-info-depth command, second time"
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clean_restart ${binfile}
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if ![runto breakpt] {
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return -1
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}
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set test_name "check mi -stack-list-frames command, first time"
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send_gdb "interpreter-exec mi \"-stack-list-frames\"\n"
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gdb_expect {
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-re "\\^done,stack=\\\[frame=\{level=\"0\",addr=\"$hex\",func=\"breakpt\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\},frame=\{level=\"1\",addr=\"$hex\",func=\"func5\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\},frame=\{level=\"2\",addr=\"$hex\",func=\"func4\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\},frame=\{level=\"3\",addr=\"$hex\",func=\"func3\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\}\\\]\r\n$gdb_prompt $" {
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pass $test_name
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}
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-re "\\^error,msg=\"Cannot access memory at address $hex\"\r\n$gdb_prompt $" {
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xfail $test_name
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}
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}
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gdb_test "interpreter-exec mi \"-stack-list-frames\"" \
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"\\^done,stack=\\\[frame=\{level=\"0\",addr=\"$hex\",func=\"breakpt\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\},frame=\{level=\"1\",addr=\"$hex\",func=\"func5\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\},frame=\{level=\"2\",addr=\"$hex\",func=\"func4\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\},frame=\{level=\"3\",addr=\"$hex\",func=\"func3\",file=\"\[^\"\]+\",fullname=\"\[^\"\]+\",line=\"${decimal}\"\}\\\]" \
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"check mi -stack-list-frames command, second time"
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||||
|
|
@ -0,0 +1,73 @@
|
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/* This testcase is part of GDB, the GNU debugger.
|
||||
|
||||
Copyright 2014 Free Software Foundation, Inc.
|
||||
|
||||
This program is free software; you can redistribute it and/or modify
|
||||
it under the terms of the GNU General Public License as published by
|
||||
the Free Software Foundation; either version 3 of the License, or
|
||||
(at your option) any later version.
|
||||
|
||||
This program is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
GNU General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU General Public License
|
||||
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
#include <sys/mman.h>
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#include <unistd.h>
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#include <assert.h>
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|
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void *global_invalid_ptr = NULL;
|
||||
|
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void
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func2 (void)
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{
|
||||
/* Replace the current stack pointer and frame pointer with the invalid
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pointer. */
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asm ("mov %0, %%rsp\n\tmov %0, %%rbp" : : "r" (global_invalid_ptr));
|
||||
|
||||
/* Create a label for a breakpoint. */
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asm (".global breakpt\nbreakpt:");
|
||||
}
|
||||
|
||||
void
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func1 (void *ptr)
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{
|
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global_invalid_ptr = ptr;
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||||
func2 ();
|
||||
}
|
||||
|
||||
/* Finds and returns an invalid pointer, mmaps in a page, grabs a pointer
|
||||
to it then unmaps the page again. This is almost certainly "undefined"
|
||||
behaviour, but should be good enough for this small test program. */
|
||||
|
||||
static void *
|
||||
make_invalid_ptr (void)
|
||||
{
|
||||
int page_size, ans;
|
||||
void *ptr;
|
||||
|
||||
page_size = getpagesize ();
|
||||
ptr = mmap (0, page_size, PROT_NONE,
|
||||
MAP_PRIVATE | MAP_ANONYMOUS,
|
||||
-1, 0);
|
||||
assert (ptr != MAP_FAILED);
|
||||
ans = munmap (ptr, page_size);
|
||||
assert (ans == 0);
|
||||
|
||||
return ptr;
|
||||
}
|
||||
|
||||
int
|
||||
main (void)
|
||||
{
|
||||
void *invalid_ptr;
|
||||
|
||||
invalid_ptr = make_invalid_ptr ();
|
||||
func1 (invalid_ptr);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -0,0 +1,111 @@
|
|||
# Copyright (C) 2014 Free Software Foundation, Inc.
|
||||
#
|
||||
# This program is free software; you can redistribute it and/or modify
|
||||
# it under the terms of the GNU General Public License as published by
|
||||
# the Free Software Foundation; either version 3 of the License, or
|
||||
# (at your option) any later version.
|
||||
#
|
||||
# This program is distributed in the hope that it will be useful,
|
||||
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
# GNU General Public License for more details.
|
||||
#
|
||||
# You should have received a copy of the GNU General Public License
|
||||
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
# In this test we're looking at how gdb handles backtraces and
|
||||
# investigating the stack depth when confronted with an "invalid" stack,
|
||||
# that is a stack where the first few frames are normal, and then there's a
|
||||
# frame where the stack in unreadable.
|
||||
#
|
||||
# One interesting bug that has been observed is that gdb will sometime
|
||||
# exhibit different behaviour the first time a stack command is run
|
||||
# compared to the second (and later) times a command is run. This is
|
||||
# because the first time a command is run gdb actually tries to figure out
|
||||
# the answer, while the second (and later) times gdb relies on the answer
|
||||
# cached from the first time. As a result in this test each command is
|
||||
# run twice, and we restart gdb before testing each different command to
|
||||
# ensure that nothing is being cached.
|
||||
|
||||
set opts {}
|
||||
standard_testfile .c
|
||||
|
||||
if { ![istarget x86_64-*-* ] || ![is_lp64_target] } {
|
||||
verbose "Skipping ${testfile}."
|
||||
return
|
||||
}
|
||||
if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} $opts] } {
|
||||
return -1
|
||||
}
|
||||
|
||||
if ![runto breakpt] {
|
||||
return -1
|
||||
}
|
||||
|
||||
# Use 'bt no-filters' here as the python filters will raise their own
|
||||
# error during initialisation, the no-filters case is simpler.
|
||||
|
||||
gdb_test "bt no-filters" "^bt no-filters\r\n#0 +$hex in func2 \\(\\)\r\nCannot access memory at address 0x\[0-9a-f\]+" \
|
||||
"first backtrace, with error message"
|
||||
|
||||
send_gdb "bt no-filters\n"
|
||||
gdb_expect {
|
||||
-re "^bt no-filters\r\n#0 +$hex in func2 \\(\\)\r\nCannot access memory at address 0x\[0-9a-f\]+\r\n$gdb_prompt $" {
|
||||
# Currently gdb will not display the error message associated with
|
||||
# the truncated backtrace after the first backtrace has been
|
||||
# completed. Ideally, we would do this. If this case is ever hit
|
||||
# then we have started to display the backtrace in all cases and
|
||||
# the xpass should becomd a pass, and the previous pass case below
|
||||
# should be removed, or changed to a fail.
|
||||
xpass "second backtrace, with error message"
|
||||
}
|
||||
-re "^bt no-filters\r\n#0 +$hex in func2 \\(\\)\r\n$gdb_prompt $" {
|
||||
pass "second backtrace, without error message"
|
||||
}
|
||||
timeout {
|
||||
fail "second backtrace (timeout)"
|
||||
}
|
||||
}
|
||||
|
||||
clean_restart ${binfile}
|
||||
|
||||
if ![runto breakpt] {
|
||||
return -1
|
||||
}
|
||||
|
||||
set test_name "check mi -stack-info-depth command, first time"
|
||||
send_gdb "interpreter-exec mi \"-stack-info-depth\"\n"
|
||||
gdb_expect {
|
||||
-re "\\^done,depth=\"1\"\r\n$gdb_prompt $" {
|
||||
pass $test_name
|
||||
}
|
||||
-re "\\^error,msg=\"Cannot access memory at address $hex\"\r\n$gdb_prompt $" {
|
||||
xfail $test_name
|
||||
}
|
||||
}
|
||||
|
||||
gdb_test "interpreter-exec mi \"-stack-info-depth\"" \
|
||||
"\\^done,depth=\"1\"" \
|
||||
"check mi -stack-info-depth command, second time"
|
||||
|
||||
clean_restart ${binfile}
|
||||
|
||||
if ![runto breakpt] {
|
||||
return -1
|
||||
}
|
||||
|
||||
set test_name "check mi -stack-list-frames command, first time"
|
||||
send_gdb "interpreter-exec mi \"-stack-list-frames\"\n"
|
||||
gdb_expect {
|
||||
-re "\\^done,stack=\\\[frame=\{level=\"0\",addr=\"$hex\",func=\"func2\"\}\\\]\r\n$gdb_prompt $" {
|
||||
pass $test_name
|
||||
}
|
||||
-re "\\^error,msg=\"Cannot access memory at address $hex\"\r\n$gdb_prompt $" {
|
||||
xfail $test_name
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
gdb_test "interpreter-exec mi \"-stack-list-frames\"" \
|
||||
"\\^done,stack=\\\[frame=\{level=\"0\",addr=\"$hex\",func=\"func2\"\}\\\]" \
|
||||
"check mi -stack-list-frames command, second time"
|
||||
Loading…
Reference in New Issue