a87c07ece5
- Fix crash when reading core [bsc #1109013] * Add gdb-fix-crash-when-reading-core.patch https://sourceware.org/ml/gdb-cvs/2018-11/msg00022.html OBS-URL: https://build.opensuse.org/request/show/647075 OBS-URL: https://build.opensuse.org/package/show/devel:gcc/gdb?expand=0&rev=195
221 lines
6.4 KiB
Diff
221 lines
6.4 KiB
Diff
From 31aceee86308321c2ef299e50773d0043e458e7f Mon Sep 17 00:00:00 2001
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From: Tom de Vries <tdevries@suse.de>
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Date: Thu, 1 Nov 2018 09:21:18 +0100
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Subject: [PATCH] [gdb] Fix gdb crash when reading core file
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Consider the test-case from this patch, compiled with O0.
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The executable segfaults, and generates a core dump:
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...
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$ ./a.out
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Segmentation fault (core dumped)
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...
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When loading the core file, limiting stack size to 4MB, gdb crashes:
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...
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$ ulimit -s 4096
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$ gdb -batch ./a.out core.saved
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[New LWP 19379]
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Segmentation fault (core dumped)
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...
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The crash originates here in linux_vsyscall_range_raw, where we call alloca
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with phdrs_size == 4194112 (roughly 4MB):
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...
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phdrs = (Elf_Internal_Phdr *) alloca (phdrs_size);
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...
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While for this test-case gdb runs fine with the system default stack limit of
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8MB, there are cases reported of 12MB phdrs_size where gdb also crashes with
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the system default stack limit.
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Fix this by using xmalloc instead of alloca, which prevents the crash provided
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the stack limit is at least 112kb.
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Build and reg-tested on x86_64-linux.
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2018-11-06 Tom de Vries <tdevries@suse.de>
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* linux-tdep.c (linux_vsyscall_range_raw): Use xmalloc to allocate
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program headers.
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* gdb.base/many-headers.c: New test.
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* gdb.base/many-headers.exp: New file.
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---
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gdb/ChangeLog | 5 +++
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gdb/linux-tdep.c | 12 +++---
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gdb/testsuite/ChangeLog | 5 +++
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gdb/testsuite/gdb.base/many-headers.c | 50 ++++++++++++++++++++++++
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gdb/testsuite/gdb.base/many-headers.exp | 67 +++++++++++++++++++++++++++++++++
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5 files changed, 133 insertions(+), 6 deletions(-)
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create mode 100644 gdb/testsuite/gdb.base/many-headers.c
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create mode 100644 gdb/testsuite/gdb.base/many-headers.exp
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diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
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index c958c0dfe9..2c766808f0 100644
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--- a/gdb/linux-tdep.c
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+++ b/gdb/linux-tdep.c
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@@ -2269,7 +2269,6 @@ linux_vsyscall_range_raw (struct gdbarch *gdbarch, struct mem_range *range)
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the vDSO. */
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if (!target_has_execution)
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{
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- Elf_Internal_Phdr *phdrs;
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long phdrs_size;
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int num_phdrs, i;
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@@ -2277,16 +2276,17 @@ linux_vsyscall_range_raw (struct gdbarch *gdbarch, struct mem_range *range)
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if (phdrs_size == -1)
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return 0;
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- phdrs = (Elf_Internal_Phdr *) alloca (phdrs_size);
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- num_phdrs = bfd_get_elf_phdrs (core_bfd, phdrs);
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+ gdb::unique_xmalloc_ptr<Elf_Internal_Phdr>
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+ phdrs ((Elf_Internal_Phdr *) xmalloc (phdrs_size));
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+ num_phdrs = bfd_get_elf_phdrs (core_bfd, phdrs.get ());
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if (num_phdrs == -1)
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return 0;
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for (i = 0; i < num_phdrs; i++)
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- if (phdrs[i].p_type == PT_LOAD
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- && phdrs[i].p_vaddr == range->start)
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+ if (phdrs.get ()[i].p_type == PT_LOAD
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+ && phdrs.get ()[i].p_vaddr == range->start)
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{
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- range->length = phdrs[i].p_memsz;
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+ range->length = phdrs.get ()[i].p_memsz;
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return 1;
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}
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diff --git a/gdb/testsuite/gdb.base/many-headers.c b/gdb/testsuite/gdb.base/many-headers.c
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new file mode 100644
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index 0000000000..49675b4e40
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--- /dev/null
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+++ b/gdb/testsuite/gdb.base/many-headers.c
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@@ -0,0 +1,50 @@
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+/* This testcase is part of GDB, the GNU debugger.
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+
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+ Copyright 2018 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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+
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+#include <stdio.h>
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+#include <malloc.h>
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+#include <sys/mman.h>
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+
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+int
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+main (void)
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+{
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+ char *ptr;
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+ int ind, cnt;
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+
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+ cnt = 100000;
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+ for (ind = 0; ind < cnt; ind++)
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+ {
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+ ptr = mmap (NULL, 100, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
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+ if (ptr == NULL)
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+ {
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+ fprintf (stderr, "Error allocating memory using mmap\n");
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+ return -1;
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+ }
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+
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+ ptr = mmap (NULL, 100, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
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+ if (ptr == NULL)
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+ {
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+ fprintf (stderr, "Error allocating memory using mmap\n");
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+ return -1;
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+ }
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+ }
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+
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+ ptr = NULL;
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+ *ptr = '\0';
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+
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+ return 0;
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+}
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diff --git a/gdb/testsuite/gdb.base/many-headers.exp b/gdb/testsuite/gdb.base/many-headers.exp
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new file mode 100644
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index 0000000000..f02b291e36
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--- /dev/null
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+++ b/gdb/testsuite/gdb.base/many-headers.exp
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@@ -0,0 +1,67 @@
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+# Copyright 2018 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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+
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+# Test if gdb can read a core file with a program header size of 4MB, if the
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+# stack size is limited to 4MB.
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+
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+if { [target_info gdb_protocol] != "" } {
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+ # Even though the feature under features being tested are supported by
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+ # gdbserver, the way this test is written doesn't make it easy with a
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+ # remote target.
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+ unsupported "not native"
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+ return
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+}
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+
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+standard_testfile
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+
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+if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
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+ return -1
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+}
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+
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+# Generate core file.
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+set corefile [core_find $binfile]
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+if {$corefile == ""} {
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+ return 0
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+}
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+
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+# Limit is in kb, so this is 4MB.
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+set stack_limit 4096
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+
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+# Verify if we can set the stack limit.
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+catch {
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+ system [concat \
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+ "(" \
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+ "ulimit -s $stack_limit;" \
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+ ")"]
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+} msg
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+if { "$msg" != "" } {
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+ untested "Can't set stack limit"
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+ return -1
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+}
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+
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+# Run gdb with stack limit
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+catch {
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+ system [concat \
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+ "(" \
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+ "ulimit -s $stack_limit;" \
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+ "$GDB $INTERNAL_GDBFLAGS $GDBFLAGS -batch -core=$corefile" \
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+ ")"]
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+} msg
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+set test "read core file"
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+if { "$msg" == "" } {
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+ pass "$test"
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+} else {
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+ fail "$test"
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+}
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--
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2.16.4
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