Messages in this thread | | | From | Mathieu Poirier <> | Date | Wed, 7 Mar 2018 14:09:24 -0700 | Subject | Re: [PATCH] perf machine: Fix load kernel symbol with '-k' option |
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Hi Leo,
On 27 February 2018 at 00:17, Leo Yan <leo.yan@linaro.org> wrote: > On Hikey arm64 octa A53 platform, when use command './perf report -v > -k vmlinux --stdio' it outputs below error info, and it skips to load > kernel symbol and doesn't print symbol for event: > Failed to open [kernel.kallsyms]_text, continuing without symbols. > > The regression is introduced by commit ("8c7f1bb37b29 perf machine: Move > kernel mmap name into struct machine"), which changes the logic for > machine mmap_name by removing function machine__mmap_name() and always > use 'machine->mmap_name'. Comparing difference between > machine__mmap_name() and 'machine->mmap_name', the later one includes > the string for specified kernel vmlinux string with option '-k' in > command, but the old function machine__mmap_name() ignores vmlinux > path string. As result, event's mmap file name doesn't match with > machine mmap file name anymore and it skips to load kernel symbol from > vmlinux file. > > To resolve this issue, this patch adds extra checking for > 'machine->mmap_name', when its start char is not '[' then we can know > it includes vmlinux path string specified for option '-k'. For this > case it sets 'is_kernel_mmap = true' and run into flow to load kernel > symbol from vmlinux. > > This patch has been verified with two commands: './perf report -v > -k vmlinux --stdio' and './perf script -v -F cpu,event,ip,sym,symoff > -k vmlinux'. > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/util/machine.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index 12b7427..ffd709d 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -1299,9 +1299,18 @@ static int machine__process_kernel_mmap_event(struct machine *machine, > else > kernel_type = DSO_TYPE_GUEST_KERNEL; > > - is_kernel_mmap = memcmp(event->mmap.filename, > - machine->mmap_name, > - strlen(machine->mmap_name) - 1) == 0; > + /* > + * If machine mmap_name doesn't start with char '[', it includes > + * the specified kernel vmlinux name with option '-k'. So set > + * is_kernel_mmap as true to create machine symbol map. > + */ > + if (machine->mmap_name[0] != '[')
I have tested your patch and it indeed solves the problem but I suggest to replace the above with:
if (symbol_conf.vmlinux_name)
That is consistent with the test in function machine__set_mmap_name() and doesn't rely on a user specified input to operate properly.
Thanks, Mathieu
> + is_kernel_mmap = true; > + else > + is_kernel_mmap = memcmp(event->mmap.filename, > + machine->mmap_name, > + strlen(machine->mmap_name) - 1) == 0; > + > if (event->mmap.filename[0] == '/' || > (!is_kernel_mmap && event->mmap.filename[0] == '[')) { > map = machine__findnew_module_map(machine, event->mmap.start, > -- > 2.7.4 >
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