From d90b8f2632cded4792f18d8bb92bacc21d93eb0a Mon Sep 17 00:00:00 2001 From: Alan Hayward Date: Wed, 21 Aug 2019 15:36:37 +0100 Subject: [PATCH] Check arguments for all probes before using them There is a long standing bug in the Arm toolchain where invalid stap probes get created due to the probes referring to symbols which have been resolved away. More details are here: https://bugzilla.redhat.com/show_bug.cgi?id=1196181 When these invalid probes are present, GDB will create the breakpoints and then fail to stop. The errors are only spotted the first time GDB stops, which is too late. The solution is to ensure the arguments for all the probes are resolved before using them. This fixes >100 timeouts when running break-interp.exp when using bad probes. gdb/ChangeLog: * solib-svr4.c (svr4_find_and_create_probe_breakpoints): Check all probe arguments. --- gdb/ChangeLog | 5 +++++ gdb/solib-svr4.c | 18 ++++++++++++++---- 2 files changed, 19 insertions(+), 4 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index d0e4258c4f7..08615f462e1 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2019-09-02 Alan Hayward + + * solib-svr4.c (svr4_find_and_create_probe_breakpoints): Check all + probe arguments. + 2019-09-02 Alan Hayward * break-catch-throw.c (fetch_probe_arguments): Use gdbarch. diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c index 2a44dd69858..ffae26bfc5f 100644 --- a/gdb/solib-svr4.c +++ b/gdb/solib-svr4.c @@ -2071,7 +2071,6 @@ svr4_find_and_create_probe_breakpoints (svr4_info *info, bool with_prefix) { std::vector probes[NUM_PROBES]; - bool checked_can_use_probe_arguments = false; for (int i = 0; i < NUM_PROBES; i++) { @@ -2102,12 +2101,23 @@ svr4_find_and_create_probe_breakpoints (svr4_info *info, return false; /* Ensure probe arguments can be evaluated. */ - if (!checked_can_use_probe_arguments) + for (probe *p : probes[i]) { - probe *p = probes[i][0]; if (!p->can_evaluate_arguments ()) return false; - checked_can_use_probe_arguments = true; + /* This will fail if the probe is invalid. This has been seen on Arm + due to references to symbols that have been resolved away. */ + try + { + p->get_argument_count (gdbarch); + } + catch (const gdb_exception_error &ex) + { + exception_print (gdb_stderr, ex); + warning (_("Initializing probes-based dynamic linker interface " + "failed.\nReverting to original interface.")); + return false; + } } } -- 2.30.2