perf tool: Fix symbol offset computation for some dsos

PATCH In review David Ahern 3 participants 3 messages Jul 28, 2013 – Sep 3, 2013 perf events

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David Ahern

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2013-07-28 15:48 UTC #0 lore raw

PATCH 1/1 perf tool: Fix symbol offset computation for some dsos

For some dsos (e.g., libc, libpthread, kernel modules) the symbol offset is huge. e.g.,

qemu-kvm 17238/17242 [007] 762235.640311:

    ffffffff816288a1 __schedule+0x451 ([kernel.kallsyms])
    ffffffff81629609 schedule+0x29 ([kernel.kallsyms])
    ffffffffa00a6ded kvm_vcpu_block+0xffffffffa00a106d (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00bae6b kvm_arch_vcpu_ioctl_run+0xffffffffa00a118b (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00a4d7a kvm_vcpu_ioctl+0xffffffffa00a141a (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffff811a7bdb do_vfs_ioctl+0x8b ([kernel.kallsyms])
    ffffffff811a80c1 sys_ioctl+0x91 ([kernel.kallsyms])
    ffffffff81633182 system_call+0x72 ([kernel.kallsyms])
        7f882a97af27 __GI___ioctl+0x7f882a891007 (/lib64/libc-2.14.90.so)
           100000002 [unknown] ([unknown])

It seems to be maps with a non-0 start. Taking that into account the offsets are correct:

qemu-kvm 17238/17242 [007] 762235.640311:

    ffffffff816288a1 __schedule+0x451 ([kernel.kallsyms])
    ffffffff81629609 schedule+0x29 ([kernel.kallsyms])
    ffffffffa00a6ded kvm_vcpu_block+0x6d (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00bae6b kvm_arch_vcpu_ioctl_run+0x18b (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00a4d7a kvm_vcpu_ioctl+0x41a (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffff811a7bdb do_vfs_ioctl+0x8b ([kernel.kallsyms])
    ffffffff811a80c1 sys_ioctl+0x91 ([kernel.kallsyms])
    ffffffff81633182 system_call+0x72 ([kernel.kallsyms])
        7f882a97af27 __GI___ioctl+0x7 (/lib64/libc-2.14.90.so)
           100000002 [unknown] ([unknown])

Signed-off-by David Ahern <[email protected]>

---
 tools/perf/util/session.c |    1 +
 tools/perf/util/symbol.c  |    5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

tools/perf/util/session.c +1 -0

index 38320ac..8f9ba44 100644
@@ -1413,6 +1413,7 @@ void perf_evsel__print_ip(struct perf_evsel *evsel, union perf_event *event,
 				printf(" ");
 				if (print_symoffset) {
 					al.addr = node->ip;
+					al.map  = node->map;
 					symbol__fprintf_symname_offs(node->sym, &al, stdout);
 				} else
 					symbol__fprintf_symname(node->sym, stdout);

tools/perf/util/symbol.c +4 -1

index 02718e7..2264733 100644
@@ -248,7 +248,10 @@ size_t symbol__fprintf_symname_offs(const struct symbol *sym,
 	if (sym && sym->name) {
 		length = fprintf(fp, "%s", sym->name);
 		if (al) {
-			offset = al->addr - sym->start;
+			if (al->addr < sym->end)
+				offset = al->addr - sym->start;
+			else
+				offset = al->addr - al->map->start - sym->start;
 			length += fprintf(fp, "+0x%lx", offset);
 		}
 		return length;

Signature · 1 line

1.7.10.1

Arnaldo Carvalho de Melo

2013-07-29 20:24 UTC #1 lore raw

Em Sun, Jul 28, 2013 at 09:48:32AM -0600, David Ahern escreveu:

Quoted 15 lines

For some dsos (e.g., libc, libpthread, kernel modules) the symbol offset is huge. e.g.,

qemu-kvm 17238/17242 [007] 762235.640311:

    ffffffff816288a1 __schedule+0x451 ([kernel.kallsyms])
    ffffffff81629609 schedule+0x29 ([kernel.kallsyms])
    ffffffffa00a6ded kvm_vcpu_block+0xffffffffa00a106d (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00bae6b kvm_arch_vcpu_ioctl_run+0xffffffffa00a118b (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00a4d7a kvm_vcpu_ioctl+0xffffffffa00a141a (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffff811a7bdb do_vfs_ioctl+0x8b ([kernel.kallsyms])
    ffffffff811a80c1 sys_ioctl+0x91 ([kernel.kallsyms])
    ffffffff81633182 system_call+0x72 ([kernel.kallsyms])
        7f882a97af27 __GI___ioctl+0x7f882a891007 (/lib64/libc-2.14.90.so)
           100000002 [unknown] ([unknown])

Quoted 2 lines

It seems to be maps with a non-0 start. Taking that into account the offsets are correct:

Humm, first reaction is that this should be solved by using one of the ->map/->unmap methods, no?

- Arnaldo

tip-bot for David Ahern

merge bot

2013-09-03 07:16 UTC #2 lore raw

[tip:perf/core] perf tools: Fix symbol offset computation for some dsos

In reply to David Ahern

perf tools: Fix symbol offset computation for some dsos

Commit-ID:  0b8c25d949e010274c6697c570b772797ebc7c27
Gitweb:     http://git.kernel.org/tip/0b8c25d949e010274c6697c570b772797ebc7c27
Author:     David Ahern <[email protected]>
AuthorDate: Sun, 28 Jul 2013 09:48:32 -0600
Committer:  Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Mon, 2 Sep 2013 14:58:21 -0300

perf tools: Fix symbol offset computation for some dsos

For some dsos (e.g., libc, libpthread, kernel modules) the symbol offset is huge. e.g.,

qemu-kvm 17238/17242 [007] 762235.640311:

    ffffffff816288a1 __schedule+0x451 ([kernel.kallsyms])
    ffffffff81629609 schedule+0x29 ([kernel.kallsyms])
    ffffffffa00a6ded kvm_vcpu_block+0xffffffffa00a106d (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00bae6b kvm_arch_vcpu_ioctl_run+0xffffffffa00a118b (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00a4d7a kvm_vcpu_ioctl+0xffffffffa00a141a (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffff811a7bdb do_vfs_ioctl+0x8b ([kernel.kallsyms])
    ffffffff811a80c1 sys_ioctl+0x91 ([kernel.kallsyms])
    ffffffff81633182 system_call+0x72 ([kernel.kallsyms])
        7f882a97af27 __GI___ioctl+0x7f882a891007 (/lib64/libc-2.14.90.so)
           100000002 [unknown] ([unknown])

It seems to be maps with a non-0 start. Taking that into account the offsets are correct:

qemu-kvm 17238/17242 [007] 762235.640311:

    ffffffff816288a1 __schedule+0x451 ([kernel.kallsyms])
    ffffffff81629609 schedule+0x29 ([kernel.kallsyms])
    ffffffffa00a6ded kvm_vcpu_block+0x6d (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00bae6b kvm_arch_vcpu_ioctl_run+0x18b (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffffa00a4d7a kvm_vcpu_ioctl+0x41a (/lib/modules/3.11.0-rc1+/kernel/arch/x86/kvm/kvm.ko)
    ffffffff811a7bdb do_vfs_ioctl+0x8b ([kernel.kallsyms])
    ffffffff811a80c1 sys_ioctl+0x91 ([kernel.kallsyms])
    ffffffff81633182 system_call+0x72 ([kernel.kallsyms])
        7f882a97af27 __GI___ioctl+0x7 (/lib64/libc-2.14.90.so)
           100000002 [unknown] ([unknown])

Signed-off-by David Ahern <[email protected]>

Link http://lkml.kernel.org/r/[email protected] open here

Signed-off-by Arnaldo Carvalho de Melo <[email protected]>

---
 tools/perf/util/session.c | 1 +
 tools/perf/util/symbol.c  | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

tools/perf/util/session.c +1 -0

index 07642a7..1fc0c62 100644
@@ -1513,6 +1513,7 @@ void perf_evsel__print_ip(struct perf_evsel *evsel, union perf_event *event,
 				printf(" ");
 				if (print_symoffset) {
 					al.addr = node->ip;
+					al.map  = node->map;
 					symbol__fprintf_symname_offs(node->sym, &al, stdout);
 				} else
 					symbol__fprintf_symname(node->sym, stdout);

tools/perf/util/symbol.c +4 -1

index 77f3b95..7eb0362 100644
@@ -259,7 +259,10 @@ size_t symbol__fprintf_symname_offs(const struct symbol *sym,
 	if (sym && sym->name) {
 		length = fprintf(fp, "%s", sym->name);
 		if (al) {
-			offset = al->addr - sym->start;
+			if (al->addr < sym->end)
+				offset = al->addr - sym->start;
+			else
+				offset = al->addr - al->map->start - sym->start;
 			length += fprintf(fp, "+0x%lx", offset);
 		}
 		return length;