* [PATCH 1/1 perf-tools-next] perf symbols: Handle 'u' symbols in /proc/kallsyms
@ 2025-04-29 15:53 Arnaldo Carvalho de Melo
2025-04-29 21:07 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 2+ messages in thread
From: Arnaldo Carvalho de Melo @ 2025-04-29 15:53 UTC (permalink / raw)
To: Namhyung Kim
Cc: Miguel Ojeda, Masahiro Yamada, Adrian Hunter, Ian Rogers,
James Clark, Jiri Olsa, Kan Liang, linux-perf-users, linux-kernel
I started seeing this in recent Fedora 42 kernels:
# uname -a
Linux number 6.14.3-300.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Sun Apr 20 16:08:39 UTC 2025 x86_64 GNU/Linux
#
# perf test vmlinux
1: vmlinux symtab matches kallsyms : FAILED!
#
Where we have Rust enabled:
# grep CONFIG_RUST /boot/config-6.14.3-300.fc42.x86_64
CONFIG_RUSTC_VERSION=108600
CONFIG_RUST_IS_AVAILABLE=y
CONFIG_RUSTC_LLVM_VERSION=200101
CONFIG_RUSTC_HAS_COERCE_POINTEE=y
CONFIG_RUST=y
CONFIG_RUSTC_VERSION_TEXT="rustc 1.86.0 (05f9846f8 2025-03-31) (Fedora 1.86.0-1.fc42)"
CONFIG_RUST_FW_LOADER_ABSTRACTIONS=y
CONFIG_RUST_PHYLIB_ABSTRACTIONS=y
# CONFIG_RUST_DEBUG_ASSERTIONS is not set
CONFIG_RUST_OVERFLOW_CHECKS=y
# CONFIG_RUST_BUILD_ASSERT_ALLOW is not set
#
Looking at the reason for the failure:
# perf test -v vmlinux |& grep ^ERR
ERR : 0xffffffff99efc7d0: __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ not on kallsyms
ERR : 0xffffffff99efc7e0: _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ not on kallsyms
#
But:
# grep -w u /proc/kallsyms
ffffffff99efc7d0 u __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
ffffffff99efc7e0 u _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
#
The test checks that "vmlinux symtab matches kallsyms", so it finds those two
symbols in vmlinux:
# pahole --running_kernel_vmlinux
/usr/lib/debug/lib/modules/6.14.3-300.fc42.x86_64/vmlinux
#
# readelf -sW /usr/lib/debug/lib/modules/6.14.3-300.fc42.x86_64/vmlinux | grep -Ew '(__pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_|_RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_)'
81844: ffffffff81efc7e0 524 FUNC LOCAL DEFAULT 1 _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
144259: ffffffff81efc7d0 16 FUNC LOCAL DEFAULT 1 __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
#
It is there.
So lets consider 'u' symbols in /proc/kallsyms when loading it to cover this case.
With this patch 'perf test 1' is happy again:
# perf test vmlinux
1: vmlinux symtab matches kallsyms : Ok
#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/symbol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 11540219481ba826..8b3975752553ff37 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -101,7 +101,7 @@ static enum dso_binary_type binary_type_symtab[] = {
static bool symbol_type__filter(char symbol_type)
{
symbol_type = toupper(symbol_type);
- return symbol_type == 'T' || symbol_type == 'W' || symbol_type == 'D' || symbol_type == 'B';
+ return symbol_type == 'T' || symbol_type == 'W' || symbol_type == 'D' || symbol_type == 'B' || symbol_type == 'U';
}
static int prefix_underscores_count(const char *str)
--
2.49.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 1/1 perf-tools-next] perf symbols: Handle 'u' symbols in /proc/kallsyms
2025-04-29 15:53 [PATCH 1/1 perf-tools-next] perf symbols: Handle 'u' symbols in /proc/kallsyms Arnaldo Carvalho de Melo
@ 2025-04-29 21:07 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 2+ messages in thread
From: Arnaldo Carvalho de Melo @ 2025-04-29 21:07 UTC (permalink / raw)
To: Namhyung Kim
Cc: Miguel Ojeda, Masahiro Yamada, Adrian Hunter, Ian Rogers,
James Clark, Jiri Olsa, Kan Liang, linux-perf-users, linux-kernel
On Tue, Apr 29, 2025 at 12:53:12PM -0300, Arnaldo Carvalho de Melo wrote:
> I started seeing this in recent Fedora 42 kernels:
>
> # uname -a
> Linux number 6.14.3-300.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Sun Apr 20 16:08:39 UTC 2025 x86_64 GNU/Linux
> #
>
> # grep -w u /proc/kallsyms
> ffffffff99efc7d0 u __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
> ffffffff99efc7e0 u _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
> #
But in Fedora:40:
root@x1:~# perf test -vv 1 |& grep ERR
ERR : 0xffffffffa0cba810: __pfx__RNCINvNtNtNtCsf6ZhIMomFvR_4core4iter8adapters3map12map_try_foldjNtCs3beuliCOs5m_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ not on kallsyms
ERR : 0xffffffffa0cba820: _RNCINvNtNtNtCsf6ZhIMomFvR_4core4iter8adapters3map12map_try_foldjNtCs3beuliCOs5m_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ not on kallsyms
root@x1:~# grep __pfx__RNCINvNtNtNtCsf6ZhIMomFvR_4core4iter8adapters3map12map_try_foldjNtCs3beuliCOs5m_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ /proc/kallsyms
ffffffffa0cba810 l __pfx__RNCINvNtNtNtCsf6ZhIMomFvR_4core4iter8adapters3map12map_try_foldjNtCs3beuliCOs5m_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
root@x1:~# uname -r
6.13.9-100.fc40.x86_64
root@x1:~# uname -a
Linux x1 6.13.9-100.fc40.x86_64 #1 SMP PREEMPT_DYNAMIC Sat Mar 29 01:27:18 UTC 2025 x86_64 GNU/Linux
root@x1:~#
root@x1:~# head /etc/os-release
NAME="Fedora Linux"
VERSION="40 (Workstation Edition)"
ID=fedora
VERSION_ID=40
VERSION_CODENAME=""
PLATFORM_ID="platform:f40"
PRETTY_NAME="Fedora Linux 40 (Workstation Edition)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:40"
root@x1:~#
It appears in /proc/kallsyms as an 'l' symbol, not 'u'.
So not 'undefined', but 'local', not exported. I'll add 'l' too.
- Arnaldo
> The test checks that "vmlinux symtab matches kallsyms", so it finds those two
> symbols in vmlinux:
>
> # pahole --running_kernel_vmlinux
> /usr/lib/debug/lib/modules/6.14.3-300.fc42.x86_64/vmlinux
> #
>
> # readelf -sW /usr/lib/debug/lib/modules/6.14.3-300.fc42.x86_64/vmlinux | grep -Ew '(__pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_|_RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_)'
> 81844: ffffffff81efc7e0 524 FUNC LOCAL DEFAULT 1 _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
> 144259: ffffffff81efc7d0 16 FUNC LOCAL DEFAULT 1 __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
> #
>
> It is there.
>
> So lets consider 'u' symbols in /proc/kallsyms when loading it to cover this case.
>
> With this patch 'perf test 1' is happy again:
>
> # perf test vmlinux
> 1: vmlinux symtab matches kallsyms : Ok
> #
>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Miguel Ojeda <ojeda@kernel.org>
> Cc: James Clark <james.clark@linaro.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Kan Liang <kan.liang@linux.intel.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
> tools/perf/util/symbol.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 11540219481ba826..8b3975752553ff37 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -101,7 +101,7 @@ static enum dso_binary_type binary_type_symtab[] = {
> static bool symbol_type__filter(char symbol_type)
> {
> symbol_type = toupper(symbol_type);
> - return symbol_type == 'T' || symbol_type == 'W' || symbol_type == 'D' || symbol_type == 'B';
> + return symbol_type == 'T' || symbol_type == 'W' || symbol_type == 'D' || symbol_type == 'B' || symbol_type == 'U';
> }
>
> static int prefix_underscores_count(const char *str)
> --
> 2.49.0
>
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2025-04-29 15:53 [PATCH 1/1 perf-tools-next] perf symbols: Handle 'u' symbols in /proc/kallsyms Arnaldo Carvalho de Melo
2025-04-29 21:07 ` Arnaldo Carvalho de Melo
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