Re: [Crash-utility] [PATCH] GDB: fix completion related libstdc++ assert
Hi Lianbo,
thanks for writing the patch!
-----Original Message-----
Currently, crash may generate core dump and print the following
error when running the commands "l panic" or "p" TAB completion.
I have still not reproduce this with upstream sources, it looks like a
combination of build flags is needed, but not sure about the minimum set.
And I think that, more exactly, the gdb list command or tab-completion of
symbols cause it, so please modify like this:
---
Currently crash built with some specific flags (-D_GLIBCXX_ASSERTIONS and
etc.) may abort and print the following error when running the gdb list
command or tab-completion of symbols.
For example:
---
crash> l panic
/usr/include/c++/11/string_view:234: ...
Aborted (core dumped)
crash> p "TAB completion"
crash> p /usr/include/c++/11/string_view:234: ...
Aborted (core dumped)
When the name string is null(the length of name is zero), there
are multiple places where array access is out of bounds in the
gdb/ada-lang.c(see ada_fold_name() and ada_lookup_name_info()).
Please add this here:
---
The patch backports these gdb patches:
6a780b676637 ("Fix completion related libstdc++ assert when using
-D_GLIBCXX_DEBUG")
2ccee230f830 ("Fix off-by-one error in ada_fold_name")
---
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
---
gdb-10.2.patch | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/gdb-10.2.patch b/gdb-10.2.patch
index 1332b6638028..16165839b360 100644
--- a/gdb-10.2.patch
+++ b/gdb-10.2.patch
@@ -1591,3 +1591,32 @@
max += 2;
limit = cols / max;
if (limit != 1 && (limit * max == cols))
+--- gdb-10.2/gdb/ada-lang.c.orig
++++ gdb-10.2/gdb/ada-lang.c
+@@ -997,7 +997,7 @@ ada_fold_name (gdb::string_view name)
+ int len = name.size ();
+ GROW_VECT (fold_buffer, fold_buffer_size, len + 1);
+
+- if (name[0] == '\'')
++ if (name.size () > 0 && name[0] == '\'')
+ {
+ strncpy (fold_buffer, name.data () + 1, len - 2);
+ fold_buffer[len - 2] = '\000';
+@@ -1006,7 +1006,7 @@ ada_fold_name (gdb::string_view name)
+ {
+ int i;
+
+- for (i = 0; i <= len; i += 1)
++ for (i = 0; i < len; i++)
+ fold_buffer[i] = tolower (name[i]);
According to 2ccee230f830 ("Fix off-by-one error in ada_fold_name"),
please add this:
+ fold_buffer[i] = '\0';
We should backport gdb patches as they are if possible, for future backports.
Thanks,
Kazu
+ }
+
+@@ -13596,7 +13596,7 @@ ada_lookup_name_info::ada_lookup_name_info (const
lookup_name_info &lookup_name)
+ {
+ gdb::string_view user_name = lookup_name.name ();
+
+- if (user_name[0] == '<')
++ if (user_name.size () > 0 && user_name[0] == '<')
+ {
+ if (user_name.back () == '>')
+ m_encoded_name
--
2.20.1