From 8455d26243aef72f7b827ec0d8367b6b7816de07 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Thu, 6 Jul 2017 00:19:24 +0100 Subject: [PATCH] Fix Python unwinder frames regression The gdb.python/py-unwind.exp test is crashing GDB / leaving core dumps in the test dir, even though it all passes cleanly. The crash is not visible in gdb.sum/gdb.log because it happens as side effect of the "quit" command, while flushing the frame cache. The problem is simply a typo in a 'for' loop's condition, introduced by a recent change [4fa847d78edd ("Remove MAX_REGISTER_SIZE from py-unwind.c")], resulting in infinite loop / double-free. The new test exposes the crash, like: Running src/gdb/testsuite/gdb.python/py-unwind.exp ... ERROR: Process no longer exists gdb/ChangeLog: 2017-07-06 Pedro Alves * python/py-unwind.c (pyuw_dealloc_cache): Fix for loop condition. gdb/testsuite/ChangeLog: 2017-07-06 Pedro Alves * gdb.python/py-unwind.exp: Test flushregs. --- gdb/ChangeLog | 4 ++++ gdb/python/py-unwind.c | 2 +- gdb/testsuite/ChangeLog | 4 ++++ gdb/testsuite/gdb.python/py-unwind.exp | 3 ++- 4 files changed, 11 insertions(+), 2 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 03f30affa59..79081421221 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,7 @@ +2017-07-06 Pedro Alves + + * python/py-unwind.c (pyuw_dealloc_cache): Fix for loop condition. + 2017-07-04 Pedro Alves * gdbtypes.c (recursive_dump_type): Don't reference TYPE_STATIC. diff --git a/gdb/python/py-unwind.c b/gdb/python/py-unwind.c index 1d800a7b786..acfce7d96c1 100644 --- a/gdb/python/py-unwind.c +++ b/gdb/python/py-unwind.c @@ -595,7 +595,7 @@ pyuw_dealloc_cache (struct frame_info *this_frame, void *cache) TRACE_PY_UNWIND (3, "%s: enter", __FUNCTION__); cached_frame_info *cached_frame = (cached_frame_info *) cache; - for (int i = 0; cached_frame->reg_count; i++) + for (int i = 0; i < cached_frame->reg_count; i++) xfree (cached_frame->reg[i].data); xfree (cache); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 6160c4b398b..d6a7252d763 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2017-07-06 Pedro Alves + + * gdb.python/py-unwind.exp: Test flushregs. + 2017-06-30 Sergio Durigan Junior PR cli/21688 diff --git a/gdb/testsuite/gdb.python/py-unwind.exp b/gdb/testsuite/gdb.python/py-unwind.exp index 0a4d34fdc6c..625b04c40e3 100644 --- a/gdb/testsuite/gdb.python/py-unwind.exp +++ b/gdb/testsuite/gdb.python/py-unwind.exp @@ -51,4 +51,5 @@ gdb_test_sequence "where" "Backtrace restored by unwinder" { "\\r\\n#2 .* main \\(.*\\) at" } - +# Check that the Python unwinder frames can be flushed / released. +gdb_test "flushregs" "Register cache flushed\\." "flush frames" -- 2.30.2