From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752083AbdEIIuO (ORCPT ); Tue, 9 May 2017 04:50:14 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:29683 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750904AbdEIIuM (ORCPT ); Tue, 9 May 2017 04:50:12 -0400 From: Vegard Nossum To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Vegard Nossum Subject: [PATCH] tracing: use %pF in trace_dump_stack() Date: Tue, 9 May 2017 10:50:04 +0200 Message-Id: <20170509085004.7891-1-vegard.nossum@oracle.com> X-Mailer: git-send-email 2.12.0.rc0 X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When using trace_dump_stack() you currently just get a list of function names. It can be very useful to know exactly where a call came from, especially if there are multiple calls from one function to another. By switching trace_dump_stack() to use %pF we get the function name and the offset, which can also be further processed to give exact line number information, like this: <...>-1087 3.... 3270529us : => pty_write+0x45/0x50 => n_tty_write+0x358/0x470 => tty_write+0x189/0x2f0 => __vfs_write+0x23/0x120 => vfs_write+0xb3/0x1b0 => SyS_write+0x44/0xa0 => entry_SYSCALL_64_fastpath+0x18/0xad $ scripts/faddr2line vmlinux tty_write+0x189/0x2f0 tty_write+0x189/0x2f0: do_tty_write at drivers/tty/tty_io.c:1174 (inlined by) tty_write at drivers/tty/tty_io.c:1257 Signed-off-by: Vegard Nossum --- kernel/trace/trace_output.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 02a4aeb22c47..879909efed33 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -1073,9 +1073,7 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter, if (trace_seq_has_overflowed(s)) break; - trace_seq_puts(s, " => "); - seq_print_ip_sym(s, *p, flags); - trace_seq_putc(s, '\n'); + trace_seq_printf(s, " => %pF\n", (void *) *p); } return trace_handle_return(s); -- 2.12.0.rc0