Commit b5c09518 authored Mar 02, 2020 by Arnaldo Carvalho de Melo

perf symbols: Don't try to find a vmlinux file when looking for kernel modules



The dso->kernel value is now set to everything that is in
machine->kmaps, but that was being used to decide if vmlinux lookup is
needed, which ended up making that lookup be made for kernel modules,
that now have dso->kernel set, leading to these kinds of warnings when
running on a machine with compressed kernel modules, like fedora:31:

  [root@five ~]# perf record -F 10000 -a sleep 2
  [ perf record: Woken up 1 times to write data ]
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  lzma: fopen failed on vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
  lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
  lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
  [ perf record: Captured and wrote 1.024 MB perf.data (1366 samples) ]
  [root@five ~]#

This happens when collecting the buildid, when we find samples for
kernel modules, fix it by checking if the looked up DSO is a kernel
module by other means.

Fixes: 02213cec ("perf maps: Mark module DSOs with kernel type")
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20200302191007.GD10335@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent e4d9b04b

tools/perf/util/symbol.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -1622,7 +1622,12 @@ int dso__load(struct dso dso, struct map map)
		goto out;
		}

		if (dso->kernel) {
		kmod = dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE \|\|
		dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP \|\|
		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE \|\|
		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;

		if (dso->kernel && !kmod) {
		if (dso->kernel == DSO_TYPE_KERNEL)
		ret = dso__load_kernel_sym(dso, map);
		else if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
		@@ -1650,12 +1655,6 @@ int dso__load(struct dso dso, struct map map)
		if (!name)
		goto out;

		kmod = dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE \|\|
		dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP \|\|
		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE \|\|
		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;


		/*
		* Read the build id if possible. This is required for
		* DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work

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