From 46a3515b49ce30315e2b621525b29cd8263aed15 Mon Sep 17 00:00:00 2001 From: Markus Metzger Date: Thu, 19 Nov 2015 14:33:41 +0100 Subject: [PATCH] btrace: diagnose "record btrace pt" without libipt If GDB has been configured without libipt support, i.e. HAVE_LIBIPT is undefined, and is running on a system that supports Intel(R) Processor Trace, GDB will run into an internal error when trying to decode the trace. (gdb) record btrace (gdb) s usage (name=0x7fffffffe954 "fib-64") at src/fib.c:12 12 fprintf(stderr, "usage: %s \n", name); (gdb) info record Active record target: record-btrace Recording format: Intel(R) Processor Trace. Buffer size: 16kB. gdb/btrace.c:971: internal-error: Unexpected branch trace format. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) This requires a system with Linux kernel 4.1 or later running on a 5th Generation Intel Core processor or later. The issue is documented as PR 19297. When trying to enable branch tracing, in addition to checking the target support for the requested branch tracing format, also check whether GDB supports. it. gdb/ * btrace.c (btrace_enable): Check whether HAVE_LIBIPT is defined. testsuite/ * lib/gdb.exp (skip_btrace_pt_tests): Check for a "GDB does not support" error. --- gdb/ChangeLog | 5 +++++ gdb/btrace.c | 5 +++++ gdb/testsuite/ChangeLog | 6 ++++++ gdb/testsuite/lib/gdb.exp | 3 +++ 4 files changed, 19 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index fbc56ac13ff..9c8b9e7e364 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2015-11-26 Markus Metzger + + PR 19297 + * btrace.c (btrace_enable): Check whether HAVE_LIBIPT is defined. + 2015-11-24 Pedro Alves * NEWS: Mention that a few "info" commands now list the diff --git a/gdb/btrace.c b/gdb/btrace.c index 2bf71771bb5..35431cbdb26 100644 --- a/gdb/btrace.c +++ b/gdb/btrace.c @@ -1035,6 +1035,11 @@ btrace_enable (struct thread_info *tp, const struct btrace_config *conf) if (tp->btrace.target != NULL) return; +#if !defined (HAVE_LIBIPT) + if (conf->format == BTRACE_FORMAT_PT) + error (_("GDB does not support Intel(R) Processor Trace.")); +#endif /* !defined (HAVE_LIBIPT) */ + if (!target_supports_btrace (conf->format)) error (_("Target does not support branch tracing.")); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index fd7c1f4c268..9f6d7e67cfc 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2015-11-26 Markus Metzger + + PR 19297 + * lib/gdb.exp (skip_btrace_pt_tests): Check for a "GDB does not + support" error. + 2015-11-24 Pedro Alves PR 17539 diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp index a420181c5a2..90e86446731 100644 --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -2826,6 +2826,9 @@ gdb_caching_proc skip_btrace_pt_tests { -re "Could not enable branch tracing.*\r\n$gdb_prompt $" { set skip_btrace_tests 1 } + -re "GDB does not support.*\r\n$gdb_prompt $" { + set skip_btrace_tests 1 + } -re "^record btrace pt\r\n$gdb_prompt $" { set skip_btrace_tests 0 } -- 2.30.2