diff mbox

Fix pressing down in the TUI (Re: [RFC 8.3 0/3] Some style fixes)

Message ID 8735852e-30bc-e5c8-de20-e0511eee8132@simark.ca
State New
Headers show

Commit Message

Simon Marchi March 25, 2019, 1:36 a.m. UTC
On 2019-03-24 11:35 a.m., Simon Marchi wrote:
> Hi all,
> 
> I get an AddressSanitizer failure, and bisecting points to this commit.
> 
> I simply "start" an executable, and there is a use-after-free happening when
> trying to print the stop location.  See the dump below.

I investigated quickly, here's what I found.  We first get the symtab's fullname
with

  const char *fullname = symtab_to_fullname (s);

fullname essentially is the same as s->fullname.

The call to open_source_file that was added by this patch deallocates s->fullname
and replaces it with a new value (if though it may be an identical string).  When
we pass fullname (the local variable) to ighlighter.highlight, it still points to
now free'd memory.

The obvious patch would be to fetch fullname again after calling open_source_file,
like so:



... but maybe there's a better way?  Should we instead create a local copy of FULLNAME?

Simon

Comments

Tom Tromey March 25, 2019, 3:14 p.m. UTC | #1
>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:

Simon> The obvious patch would be to fetch fullname again after calling open_source_file,
Simon> like so:

I think this is fine, especially with a comment explaining it.

Simon> ... but maybe there's a better way?  Should we instead create a
Simon> local copy of FULLNAME?

Ideally we'd rewrite this whole area.  I don't much like stashing the
full name in the symtab, and also it seems to me that gdb calls open,
etc, far too much.

Tom
diff mbox

Patch

diff --git a/gdb/source-cache.c b/gdb/source-cache.c
index 9211f098eb70..ac97d79cdb31 100644
--- a/gdb/source-cache.c
+++ b/gdb/source-cache.c
@@ -206,6 +206,8 @@  source_cache::get_source_lines (struct symtab *s, int first_line,
 		  if (desc.get () < 0)
 		    return false;
 		  find_source_lines (s, desc.get ());
+
+		  fullname = symtab_to_fullname (s);
 		}
 	      srchilite::SourceHighlight highlighter ("esc.outlang");
 	      highlighter.setStyleFile("esc.style");