From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Clark Williams <williams@redhat.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Thomas Richter <tmricht@linux.ibm.com>,
Hendrik Brueckner <brueckner@linux.ibm.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 43/44] perf record: Fix s390 missing module symbol and warning for non-root users
Date: Mon, 27 May 2019 19:37:29 -0300 [thread overview]
Message-ID: <20190527223730.11474-44-acme@kernel.org> (raw)
In-Reply-To: <20190527223730.11474-1-acme@kernel.org>
From: Thomas Richter <tmricht@linux.ibm.com>
Command 'perf record' and 'perf report' on a system without kernel
debuginfo packages uses /proc/kallsyms and /proc/modules to find
addresses for kernel and module symbols. On x86 this works for root and
non-root users.
On s390, when invoked as non-root user, many of the following warnings
are shown and module symbols are missing:
proc/{kallsyms,modules} inconsistency while looking for
"[sha1_s390]" module!
Command 'perf record' creates a list of module start addresses by
parsing the output of /proc/modules and creates a PERF_RECORD_MMAP
record for the kernel and each module. The following function call
sequence is executed:
machine__create_kernel_maps
machine__create_module
modules__parse
machine__create_module --> for each line in /proc/modules
arch__fix_module_text_start
Function arch__fix_module_text_start() is s390 specific. It opens
file /sys/module/<name>/sections/.text to extract the module's .text
section start address. On s390 the module loader prepends a header
before the first section, whereas on x86 the module's text section
address is identical the the module's load address.
However module section files are root readable only. For non-root the
read operation fails and machine__create_module() returns an error.
Command perf record does not generate any PERF_RECORD_MMAP record
for loaded modules. Later command perf report complains about missing
module maps.
To fix this function arch__fix_module_text_start() always returns
success. For root users there is no change, for non-root users
the module's load address is used as module's text start address
(the prepended header then counts as part of the text section).
This enable non-root users to use module symbols and avoid the
warning when perf report is executed.
Output before:
[tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP
0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text
Output after:
[tmricht@m83lp54 perf]$ ./perf report -D | fgrep MMAP
0 0x168 [0x50]: PERF_RECORD_MMAP ... x [kernel.kallsyms]_text
0 0x1b8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../autofs4.ko.xz
0 0x250 [0xa8]: PERF_RECORD_MMAP ... x /lib/modules/.../sha_common.ko.xz
0 0x2f8 [0x98]: PERF_RECORD_MMAP ... x /lib/modules/.../des_generic.ko.xz
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Link: http://lkml.kernel.org/r/20190522144601.50763-4-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/arch/s390/util/machine.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/perf/arch/s390/util/machine.c b/tools/perf/arch/s390/util/machine.c
index 0b2054007314..a19690a17291 100644
--- a/tools/perf/arch/s390/util/machine.c
+++ b/tools/perf/arch/s390/util/machine.c
@@ -5,16 +5,19 @@
#include "util.h"
#include "machine.h"
#include "api/fs/fs.h"
+#include "debug.h"
int arch__fix_module_text_start(u64 *start, const char *name)
{
+ u64 m_start = *start;
char path[PATH_MAX];
snprintf(path, PATH_MAX, "module/%.*s/sections/.text",
(int)strlen(name) - 2, name + 1);
-
- if (sysfs__read_ull(path, (unsigned long long *)start) < 0)
- return -1;
+ if (sysfs__read_ull(path, (unsigned long long *)start) < 0) {
+ pr_debug2("Using module %s start:%#lx\n", path, m_start);
+ *start = m_start;
+ }
return 0;
}
--
2.20.1
next prev parent reply other threads:[~2019-05-27 22:41 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-27 22:36 [GIT PULL] perf/urgent improvements and fixes Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 01/44] perf-with-kcore.sh: Always allow fix_buildid_cache_permissions Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 02/44] perf intel-pt: Fix itrace defaults for perf script Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 03/44] perf auxtrace: " Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 04/44] perf intel-pt: Fix itrace defaults for perf script intel-pt documentation Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 05/44] perf data: Fix 'strncat may truncate' build failure with recent gcc Arnaldo Carvalho de Melo
2019-05-27 22:46 ` Shawn Landden
2019-05-28 13:04 ` Arnaldo Carvalho de Melo
2019-05-28 16:59 ` Shawn Landden
2019-05-28 17:39 ` Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 06/44] perf arm64: Fix mksyscalltbl when system kernel headers are ahead of the kernel Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 07/44] tools include UAPI: Update copy of files related to new fspick, fsmount, fsconfig, fsopen, move_mount and open_tree syscalls Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 08/44] perf augmented_raw_syscalls: Fix up comment Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 09/44] perf beauty: Add generator for 'move_mount' flags argument Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 10/44] perf trace: Beautify 'move_mount' arguments Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 11/44] perf beauty: Add generator for fspick's 'flags' arg values Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 12/44] perf trace: Beautify 'fspick' arguments Arnaldo Carvalho de Melo
2019-05-27 22:36 ` [PATCH 13/44] perf beauty: Add generator for fsconfig's 'cmd' arg values Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 14/44] perf trace: Beautify 'fsconfig' arguments Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 15/44] perf beauty: Add generator for fsmount's 'attr_flags' arg values Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 16/44] perf trace: Introduce syscall_arg__scnprintf_strarray_flags Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 17/44] perf trace: Beautify 'fsmount' arguments Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 18/44] tools arch x86: Sync asm/cpufeatures.h with the with the kernel Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 19/44] tools headers UAPI: Sync linux/sched.h " Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 20/44] perf trace beauty clone: Handle CLONE_PIDFD Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 21/44] tools headers UAPI: Sync linux/fs.h with the kernel Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 22/44] perf beauty: Add generator for sync_file_range's 'flags' arg values Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 23/44] perf trace: Beautify 'sync_file_range' arguments Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 24/44] tools headers UAPI: Sync drm/i915_drm.h with the kernel Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 25/44] tools headers UAPI: Sync drm/drm.h " Arnaldo Carvalho de Melo
2019-05-28 3:17 ` Zhou, David(ChunMing)
2019-05-28 8:07 ` Lionel Landwerlin
2019-05-28 12:53 ` Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 26/44] perf namespace: Protect reading thread's namespace Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 27/44] perf session: Add missing swap ops for namespace events Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 28/44] perf top: Add --namespaces option Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 29/44] perf tools: Remove const from thread read accessors Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 30/44] perf dso: Separate generic code in dso__data_file_size() Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 31/44] perf dso: Separate generic code in dso_cache__read Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 32/44] perf dso: Simplify dso_cache__read function Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 33/44] perf dso: Add BPF DSO read and size hooks Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 34/44] perf test vmlinux-kallsyms: Ignore aliases to _etext when searching on kallsyms Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 35/44] perf machine: Read also the end of the kernel Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 36/44] perf machine: Keep zero in pgoff BPF map Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 37/44] perf tools: Preserve eBPF maps when loading kcore Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 38/44] perf script: Pad DSO name for --call-trace Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 39/44] perf tests: Add map_groups__merge_in test Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 40/44] perf script: Add --show-bpf-events to show eBPF related events Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 41/44] perf script: Remove superfluous BPF event titles Arnaldo Carvalho de Melo
2019-05-27 22:37 ` [PATCH 42/44] perf version: Append 12 git SHA chars to the version string Arnaldo Carvalho de Melo
2019-05-27 22:37 ` Arnaldo Carvalho de Melo [this message]
2019-05-27 22:37 ` [PATCH 44/44] tools headers UAPI: Sync kvm.h headers with the kernel sources Arnaldo Carvalho de Melo
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