Messages in this thread | | | Date | Sun, 15 Apr 2012 14:59:13 -0600 | From | David Ahern <> | Subject | Re: [PATCH] perf report: fix crash showing warning related to kernel maps |
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Hi Arnaldo:
Haven't seen this one come through your urgent queue.
On 4/10/12 10:15 AM, David Ahern wrote: > While testing https://lkml.org/lkml/2012/4/10/123 I hit this crash: > > (gdb) bt > 0 0x000000000042000f in __cmd_report (rep=0x7fff80cec580) at builtin-report.c:380 > 1 cmd_report (argc=0, argv=<optimized out>, prefix=<optimized out>) at builtin-report.c:759 > 2 0x0000000000414513 in run_builtin (p=0x7724a8, argc=3, argv=0x7fff80ceca70) at perf.c:273 > 3 0x0000000000413d41 in handle_internal_command (argv=0x7fff80ceca70, argc=3) at perf.c:345 > 4 run_argv (argv=0x7fff80cec880, argcp=0x7fff80cec88c) at perf.c:389 > 5 main (argc=3, argv=0x7fff80ceca70) at perf.c:487 > > kernel_map can be NULL, so need to handle it while dumping a warning > to user. > > Signed-off-by: David Ahern<dsahern@gmail.com> > --- > tools/perf/builtin-report.c | 17 ++++++++++++----- > 1 files changed, 12 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c > index 2e31743..002c644 100644 > --- a/tools/perf/builtin-report.c > +++ b/tools/perf/builtin-report.c > @@ -374,16 +374,23 @@ static int __cmd_report(struct perf_report *rep) > (kernel_map->dso->hit&& > (kernel_kmap->ref_reloc_sym == NULL || > kernel_kmap->ref_reloc_sym->addr == 0))) { > - const struct dso *kdso = kernel_map->dso; > + const char *desc = > + "As no suitable kallsyms nor vmlinux was found, kernel samples\n" > + "can't be resolved."; > + > + if (kernel_map) { > + const struct dso *kdso = kernel_map->dso; > + if (RB_EMPTY_ROOT(&kdso->symbols[MAP__FUNCTION])) { > + desc = "If some relocation was applied (e.g. " > + "kexec) symbols may be misresolved."; > + } > + } > > ui__warning( > "Kernel address maps (/proc/{kallsyms,modules}) were restricted.\n\n" > "Check /proc/sys/kernel/kptr_restrict before running 'perf record'.\n\n%s\n\n" > "Samples in kernel modules can't be resolved as well.\n\n", > - RB_EMPTY_ROOT(&kdso->symbols[MAP__FUNCTION]) ? > -"As no suitable kallsyms nor vmlinux was found, kernel samples\n" > -"can't be resolved." : > -"If some relocation was applied (e.g. kexec) symbols may be misresolved."); > + desc); > } > > if (dump_trace) {
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