linux-kernel - Re: [PATCH] scripts/faddr2line: show the code context

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Message-ID: <20180529162636.GW12235@hirez.programming.kicks-ass.net>
Date:   Tue, 29 May 2018 18:26:36 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     changbin.du@...el.com
Cc:     akpm@...ux-foundation.org, tglx@...utronix.de,
        pombredanne@...b.com, neilb@...e.com, linux-kernel@...r.kernel.org,
        jpoimboe@...hat.com
Subject: Re: [PATCH] scripts/faddr2line: show the code context

On Tue, May 29, 2018 at 06:03:32PM +0200, Peter Zijlstra wrote:
> On Mon, Mar 19, 2018 at 03:23:25PM +0800, changbin.du@...el.com wrote:
> > From: Changbin Du <changbin.du@...el.com>
> > 
> > Inspired by gdb command 'list', show the code context of target lines.
> > Here is a example:
> > 
> > $ scripts/faddr2line vmlinux native_write_msr+0x6
> > native_write_msr+0x6/0x20:
> > arch_static_branch at arch/x86/include/asm/msr.h:105
> > 100             return EAX_EDX_VAL(val, low, high);
> > 101     }
> > 102
> > 103     static inline void notrace __wrmsr(unsigned int msr, u32 low, u32 high)
> > 104     {
> > 105             asm volatile("1: wrmsr\n"
> > 106                          "2:\n"
> > 107                          _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_unsafe)
> > 108                          : : "c" (msr), "a"(low), "d" (high) : "memory");
> > 109     }
> > 110
> > (inlined by) static_key_false at include/linux/jump_label.h:142
> > 137     #define JUMP_TYPE_LINKED        2UL
> > 138     #define JUMP_TYPE_MASK          3UL
> > 139
> > 140     static __always_inline bool static_key_false(struct static_key *key)
> > 141     {
> > 142             return arch_static_branch(key, false);
> > 143     }
> > 144
> > 145     static __always_inline bool static_key_true(struct static_key *key)
> > 146     {
> > 147             return !arch_static_branch(key, true);
> > (inlined by) native_write_msr at arch/x86/include/asm/msr.h:150
> > 145     static inline void notrace
> > 146     native_write_msr(unsigned int msr, u32 low, u32 high)
> > 147     {
> > 148             __wrmsr(msr, low, high);
> > 149
> > 150             if (msr_tracepoint_active(__tracepoint_write_msr))
> > 151                     do_trace_write_msr(msr, ((u64)high << 32 | low), 0);
> > 152     }
> > 153
> > 154     /* Can be uninlined because referenced by paravirt */
> > 155     static inline int notrace
> 
> Not a fan of this :-/ And you didn't even make it optional. Nor did you
> Cc the original author of the tool.

Something like so fixes it up and attempts to make the --list version
more readable.

---
 scripts/faddr2line | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/scripts/faddr2line b/scripts/faddr2line
index 1876a741087c..a0149db00be7 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -56,7 +56,7 @@ command -v ${SIZE} >/dev/null 2>&1 || die "size isn't installed"
 command -v ${NM} >/dev/null 2>&1 || die "nm isn't installed"
 
 usage() {
-	echo "usage: faddr2line <object file> <func+offset> <func+offset>..." >&2
+	echo "usage: faddr2line [--list] <object file> <func+offset> <func+offset>..." >&2
 	exit 1
 }
 
@@ -166,15 +166,25 @@ __faddr2line() {
 		local file_lines=$(${ADDR2LINE} -fpie $objfile $addr | sed "s; $dir_prefix\(\./\)*; ;")
 		[[ -z $file_lines ]] && return
 
+		if [[ $LIST = 0 ]]; then
+			echo "$file_lines" | while read -r line
+			do
+				echo $line
+			done
+			DONE=1;
+			return
+		fi
+
 		# show each line with context
 		echo "$file_lines" | while read -r line
 		do
+			echo
 			echo $line
 			n=$(echo $line | sed 's/.*:\([0-9]\+\).*/\1/g')
 			n1=$[$n-5]
 			n2=$[$n+5]
 			f=$(echo $line | sed 's/.*at \(.\+\):.*/\1/g')
-			awk 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") {printf("%d\t%s\n", NR, $0)}' $f
+			awk 'NR>=strtonum("'$n1'") && NR<=strtonum("'$n2'") { if (NR=='$n') printf(">%d<", NR); else printf(" %d ", NR); printf("\t%s\n", $0)}' $f
 		done
 
 		DONE=1
@@ -185,6 +195,10 @@ __faddr2line() {
 [[ $# -lt 2 ]] && usage
 
 objfile=$1
+
+LIST=0
+[[ "$objfile" == "--list" ]] && LIST=1 && shift && objfile=$1
+
 [[ ! -f $objfile ]] && die "can't find objfile $objfile"
 shift