Re: [PATCH V2 1/3] perf tools: Add fallback functions for cases where cpumode is insufficient
From: Arnaldo Carvalho de Melo
Date: Tue Nov 27 2018 - 09:10:41 EST
Em Tue, Nov 06, 2018 at 11:07:10PM +0200, Adrian Hunter escreveu:
> For branch stacks or branch samples, the sample cpumode might not be
> correct because it applies only to the sample 'ip' and not necessary to
> 'addr' or branch stack addresses. Add fallback functions that can be used
> to deal with those cases
I've split this into two, and the first is causing this:
root@quaco ~]# perf top
perf: Segmentation fault
-------- backtrace --------
perf[0x59baca]
/lib64/libc.so.6(+0x385bf)[0x7fa2775dc5bf]
perf(perf_env__arch+0x34)[0x4b4514]
perf(perf_env__single_address_space+0x1b)[0x57944b]
perf(perf_session__new+0x17c)[0x4fdb3c]
perf(cmd_top+0x162c)[0x45109c]
perf[0x4a621e]
perf(main+0x61c)[0x42cbfc]
/lib64/libc.so.6(__libc_start_main+0xf2)[0x7fa2775c8412]
perf(_start+0x2d)[0x42ce2d]
[root@quaco ~]#
Its the case where the env info comes from the running machine, via
uname(), I'm working on a fix.
- Arnaldo
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 4.19
> ---
> tools/perf/arch/common.c | 10 ++++++++++
> tools/perf/arch/common.h | 1 +
> tools/perf/util/event.c | 27 +++++++++++++++++++++++++++
> tools/perf/util/machine.c | 27 +++++++++++++++++++++++++++
> tools/perf/util/machine.h | 3 +++
> tools/perf/util/session.c | 4 ++++
> tools/perf/util/thread.h | 4 ++++
> 7 files changed, 76 insertions(+)
>
> diff --git a/tools/perf/arch/common.c b/tools/perf/arch/common.c
> index 82657c01a3b8..5f69fd0b745a 100644
> --- a/tools/perf/arch/common.c
> +++ b/tools/perf/arch/common.c
> @@ -200,3 +200,13 @@ int perf_env__lookup_objdump(struct perf_env *env, const char **path)
>
> return perf_env__lookup_binutils_path(env, "objdump", path);
> }
> +
> +/*
> + * Some architectures have a single address space for kernel and user addresses,
> + * which makes it possible to determine if an address is in kernel space or user
> + * space.
> + */
> +bool perf_env__single_address_space(struct perf_env *env)
> +{
> + return strcmp(perf_env__arch(env), "sparc");
> +}
> diff --git a/tools/perf/arch/common.h b/tools/perf/arch/common.h
> index 2167001b18c5..c298a446d1f6 100644
> --- a/tools/perf/arch/common.h
> +++ b/tools/perf/arch/common.h
> @@ -5,5 +5,6 @@
> #include "../util/env.h"
>
> int perf_env__lookup_objdump(struct perf_env *env, const char **path);
> +bool perf_env__single_address_space(struct perf_env *env);
>
> #endif /* ARCH_PERF_COMMON_H */
> diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> index e9c108a6b1c3..9431b20c1337 100644
> --- a/tools/perf/util/event.c
> +++ b/tools/perf/util/event.c
> @@ -1577,6 +1577,24 @@ struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
> return al->map;
> }
>
> +/*
> + * For branch stacks or branch samples, the sample cpumode might not be correct
> + * because it applies only to the sample 'ip' and not necessary to 'addr' or
> + * branch stack addresses. If possible, use a fallback to deal with those cases.
> + */
> +struct map *thread__find_map_fb(struct thread *thread, u8 cpumode, u64 addr,
> + struct addr_location *al)
> +{
> + struct map *map = thread__find_map(thread, cpumode, addr, al);
> + struct machine *machine = thread->mg->machine;
> + u8 addr_cpumode = machine__addr_cpumode(machine, cpumode, addr);
> +
> + if (map || addr_cpumode == cpumode)
> + return map;
> +
> + return thread__find_map(thread, addr_cpumode, addr, al);
> +}
> +
> struct symbol *thread__find_symbol(struct thread *thread, u8 cpumode,
> u64 addr, struct addr_location *al)
> {
> @@ -1586,6 +1604,15 @@ struct symbol *thread__find_symbol(struct thread *thread, u8 cpumode,
> return al->sym;
> }
>
> +struct symbol *thread__find_symbol_fb(struct thread *thread, u8 cpumode,
> + u64 addr, struct addr_location *al)
> +{
> + al->sym = NULL;
> + if (thread__find_map_fb(thread, cpumode, addr, al))
> + al->sym = map__find_symbol(al->map, al->addr);
> + return al->sym;
> +}
> +
> /*
> * Callers need to drop the reference to al->thread, obtained in
> * machine__findnew_thread()
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index 8f36ce813bc5..9397e3f2444d 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -2592,6 +2592,33 @@ int machine__get_kernel_start(struct machine *machine)
> return err;
> }
>
> +u8 machine__addr_cpumode(struct machine *machine, u8 cpumode, u64 addr)
> +{
> + u8 addr_cpumode = cpumode;
> + bool kernel_ip;
> +
> + if (!machine->single_address_space)
> + goto out;
> +
> + kernel_ip = machine__kernel_ip(machine, addr);
> + switch (cpumode) {
> + case PERF_RECORD_MISC_KERNEL:
> + case PERF_RECORD_MISC_USER:
> + addr_cpumode = kernel_ip ? PERF_RECORD_MISC_KERNEL :
> + PERF_RECORD_MISC_USER;
> + break;
> + case PERF_RECORD_MISC_GUEST_KERNEL:
> + case PERF_RECORD_MISC_GUEST_USER:
> + addr_cpumode = kernel_ip ? PERF_RECORD_MISC_GUEST_KERNEL :
> + PERF_RECORD_MISC_GUEST_USER;
> + break;
> + default:
> + break;
> + }
> +out:
> + return addr_cpumode;
> +}
> +
> struct dso *machine__findnew_dso(struct machine *machine, const char *filename)
> {
> return dsos__findnew(&machine->dsos, filename);
> diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
> index d856b85862e2..ebde3ea70225 100644
> --- a/tools/perf/util/machine.h
> +++ b/tools/perf/util/machine.h
> @@ -42,6 +42,7 @@ struct machine {
> u16 id_hdr_size;
> bool comm_exec;
> bool kptr_restrict_warned;
> + bool single_address_space;
> char *root_dir;
> char *mmap_name;
> struct threads threads[THREADS__TABLE_SIZE];
> @@ -99,6 +100,8 @@ static inline bool machine__kernel_ip(struct machine *machine, u64 ip)
> return ip >= kernel_start;
> }
>
> +u8 machine__addr_cpumode(struct machine *machine, u8 cpumode, u64 addr);
> +
> struct thread *machine__find_thread(struct machine *machine, pid_t pid,
> pid_t tid);
> struct comm *machine__thread_exec_comm(struct machine *machine,
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 7d2c8ce6cfad..f8eab197f35c 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -24,6 +24,7 @@
> #include "thread.h"
> #include "thread-stack.h"
> #include "stat.h"
> +#include "arch/common.h"
>
> static int perf_session__deliver_event(struct perf_session *session,
> union perf_event *event,
> @@ -150,6 +151,9 @@ struct perf_session *perf_session__new(struct perf_data *data,
> session->machines.host.env = &perf_env;
> }
>
> + session->machines.host.single_address_space =
> + perf_env__single_address_space(session->machines.host.env);
> +
> if (!data || perf_data__is_write(data)) {
> /*
> * In O_RDONLY mode this will be performed when reading the
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 30e2b4c165fe..5920c3bb8ffe 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -96,9 +96,13 @@ struct thread *thread__main_thread(struct machine *machine, struct thread *threa
>
> struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
> struct addr_location *al);
> +struct map *thread__find_map_fb(struct thread *thread, u8 cpumode, u64 addr,
> + struct addr_location *al);
>
> struct symbol *thread__find_symbol(struct thread *thread, u8 cpumode,
> u64 addr, struct addr_location *al);
> +struct symbol *thread__find_symbol_fb(struct thread *thread, u8 cpumode,
> + u64 addr, struct addr_location *al);
>
> void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
> struct addr_location *al);
> --
> 2.17.1
--
- Arnaldo