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Date: Mon, 3 Jul 2017 15:46:41 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Krister Johansen <kjlx@...pleofstupid.com>
Cc: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH tip/perf/core 3/7] perf probe: allow placing uprobes in
alternate namespaces.
Em Fri, Jun 30, 2017 at 07:18:55PM -0700, Krister Johansen escreveu:
> Teaches perf how to place a uprobe on a file that's in a different mount
> namespace. The user must add the probe using the --target-ns argument
> to perf probe. Once it has been placed, it may be recorded against
> without further namespace-specific commands.
>
> Signed-off-by: Krister Johansen <kjlx@...pleofstupid.com>
> ---
> tools/perf/builtin-probe.c | 44 ++++++++++++++++++++++--
> tools/perf/util/probe-event.c | 79 +++++++++++++++++++++++++++++--------------
> tools/perf/util/probe-event.h | 10 ++++--
> 3 files changed, 101 insertions(+), 32 deletions(-)
>
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index cf9f9e9..5ab2e00 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -58,6 +58,7 @@ static struct {
> struct line_range line_range;
> char *target;
> struct strfilter *filter;
> + struct nsinfo *nsi;
> } params;
>
> /* Parse an event definition. Note that any error must die. */
> @@ -80,6 +81,9 @@ static int parse_probe_event(const char *str)
> params.target_used = true;
> }
>
> + if (params.nsi)
> + pev->nsi = nsinfo__get(params.nsi);
> +
> /* Parse a perf-probe command into event */
> ret = parse_perf_probe_command(str, pev);
> pr_debug("%d arguments\n", pev->nargs);
> @@ -178,6 +182,7 @@ static int opt_set_target(const struct option *opt, const char *str,
> {
> int ret = -ENOENT;
> char *tmp;
> + struct nscookie nsc;
>
> if (str) {
> if (!strcmp(opt->long_name, "exec"))
> @@ -189,7 +194,9 @@ static int opt_set_target(const struct option *opt, const char *str,
>
> /* Expand given path to absolute path, except for modulename */
> if (params.uprobes || strchr(str, '/')) {
> + nsinfo__mountns_enter(params.nsi, &nsc);
> tmp = realpath(str, NULL);
> + nsinfo__mountns_exit(&nsc);
Perhaps have a nsinfo__realpath()? Don't know if this will be used
elsewhere, but looks shorter.
> if (!tmp) {
> pr_warning("Failed to get the absolute path of %s: %m\n", str);
> return ret;
> @@ -208,6 +215,34 @@ static int opt_set_target(const struct option *opt, const char *str,
> return ret;
> }
>
> +static int opt_set_target_ns(const struct option *opt __maybe_unused,
> + const char *str, int unset __maybe_unused)
> +{
> + int ret = -ENOENT;
> + pid_t ns_pid;
> + struct nsinfo *nsip;
> +
> + if (str) {
> + errno = 0;
> + ns_pid = (pid_t)strtol(str, NULL, 10);
> + if (errno != 0) {
> + ret = -errno;
> + pr_warning("Failed to parse %s as a pid: %s\n", str,
> + strerror(errno));
> + return ret;
> + }
> + nsip = nsinfo__new(ns_pid);
> + if (nsip && nsip->need_setns)
> + params.nsi = nsinfo__get(nsip);
> + nsinfo__put(nsip);
> +
> + ret = 0;
> + }
> +
> + return ret;
> +}
> +
> +
> /* Command option callbacks */
>
> #ifdef HAVE_DWARF_SUPPORT
> @@ -299,6 +334,7 @@ static void cleanup_params(void)
> line_range__clear(¶ms.line_range);
> free(params.target);
> strfilter__delete(params.filter);
> + nsinfo__put(params.nsi);
> memset(¶ms, 0, sizeof(params));
> }
>
> @@ -554,6 +590,8 @@ __cmd_probe(int argc, const char **argv)
> OPT_BOOLEAN(0, "cache", &probe_conf.cache, "Manipulate probe cache"),
> OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
> "Look for files with symbols relative to this directory"),
> + OPT_CALLBACK(0, "target-ns", NULL, "pid",
> + "target pid for namespace information", opt_set_target_ns),
> OPT_END()
> };
> int ret;
> @@ -634,15 +672,15 @@ __cmd_probe(int argc, const char **argv)
> pr_err_with_code(" Error: Failed to show event list.", ret);
> return ret;
> case 'F':
> - ret = show_available_funcs(params.target, params.filter,
> - params.uprobes);
> + ret = show_available_funcs(params.target, params.nsi,
> + params.filter, params.uprobes);
> if (ret < 0)
> pr_err_with_code(" Error: Failed to show functions.", ret);
> return ret;
> #ifdef HAVE_DWARF_SUPPORT
> case 'L':
> ret = show_line_range(¶ms.line_range, params.target,
> - params.uprobes);
> + params.nsi, params.uprobes);
> if (ret < 0)
> pr_err_with_code(" Error: Failed to show lines.", ret);
> return ret;
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 84e7e69..dce4f12 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -184,13 +184,19 @@ static struct map *kernel_get_module_map(const char *module)
> return NULL;
> }
>
> -struct map *get_target_map(const char *target, bool user)
> +struct map *get_target_map(const char *target, struct nsinfo *nsi, bool user)
> {
> /* Init maps of given executable or kernel */
> - if (user)
> - return dso__new_map(target);
> - else
> + if (user) {
> + struct map *map;
> +
> + map = dso__new_map(target);
> + if (map && map->dso)
> + map->dso->nsinfo = nsinfo__get(nsi);
> + return map;
> + } else {
> return kernel_get_module_map(target);
> + }
> }
>
> static int convert_exec_to_group(const char *exec, char **result)
> @@ -366,7 +372,8 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso)
> static int find_alternative_probe_point(struct debuginfo *dinfo,
> struct perf_probe_point *pp,
> struct perf_probe_point *result,
> - const char *target, bool uprobes)
> + const char *target, struct nsinfo *nsi,
> + bool uprobes)
> {
> struct map *map = NULL;
> struct symbol *sym;
> @@ -377,7 +384,7 @@ static int find_alternative_probe_point(struct debuginfo *dinfo,
> if (!pp->function || pp->file)
> return -ENOTSUP;
>
> - map = get_target_map(target, uprobes);
> + map = get_target_map(target, nsi, uprobes);
> if (!map)
> return -EINVAL;
>
> @@ -421,8 +428,8 @@ static int get_alternative_probe_event(struct debuginfo *dinfo,
>
> memcpy(tmp, &pev->point, sizeof(*tmp));
> memset(&pev->point, 0, sizeof(pev->point));
> - ret = find_alternative_probe_point(dinfo, tmp, &pev->point,
> - pev->target, pev->uprobes);
> + ret = find_alternative_probe_point(dinfo, tmp, &pev->point, pev->target,
> + pev->nsi, pev->uprobes);
> if (ret < 0)
> memcpy(&pev->point, tmp, sizeof(*tmp));
>
> @@ -444,7 +451,7 @@ static int get_alternative_line_range(struct debuginfo *dinfo,
> if (lr->end != INT_MAX)
> len = lr->end - lr->start;
> ret = find_alternative_probe_point(dinfo, &pp, &result,
> - target, user);
> + target, NULL, user);
> if (!ret) {
> lr->function = result.function;
> lr->file = result.file;
> @@ -457,12 +464,14 @@ static int get_alternative_line_range(struct debuginfo *dinfo,
> }
>
> /* Open new debuginfo of given module */
> -static struct debuginfo *open_debuginfo(const char *module, bool silent)
> +static struct debuginfo *open_debuginfo(const char *module, struct nsinfo *nsi,
> + bool silent)
> {
> const char *path = module;
> char reason[STRERR_BUFSIZE];
> struct debuginfo *ret = NULL;
> struct dso *dso = NULL;
> + struct nscookie nsc;
> int err;
>
> if (!module || !strchr(module, '/')) {
> @@ -480,6 +489,7 @@ static struct debuginfo *open_debuginfo(const char *module, bool silent)
> }
> path = dso->long_name;
> }
> + nsinfo__mountns_enter(nsi, &nsc);
> ret = debuginfo__new(path);
> if (!ret && !silent) {
> pr_warning("The %s file has no debug information.\n", path);
> @@ -489,6 +499,7 @@ static struct debuginfo *open_debuginfo(const char *module, bool silent)
> pr_warning("Rebuild with -g, ");
> pr_warning("or install an appropriate debuginfo package.\n");
> }
> + nsinfo__mountns_exit(&nsc);
> return ret;
> }
>
> @@ -516,7 +527,7 @@ static struct debuginfo *debuginfo_cache__open(const char *module, bool silent)
> goto out;
> }
>
> - debuginfo_cache = open_debuginfo(module, silent);
> + debuginfo_cache = open_debuginfo(module, NULL, silent);
> if (!debuginfo_cache)
> zfree(&debuginfo_cache_path);
> out:
> @@ -531,14 +542,18 @@ static void debuginfo_cache__exit(void)
> }
>
>
> -static int get_text_start_address(const char *exec, unsigned long *address)
> +static int get_text_start_address(const char *exec, unsigned long *address,
> + struct nsinfo *nsi)
> {
> Elf *elf;
> GElf_Ehdr ehdr;
> GElf_Shdr shdr;
> int fd, ret = -ENOENT;
> + struct nscookie nsc;
>
> + nsinfo__mountns_enter(nsi, &nsc);
> fd = open(exec, O_RDONLY);
> + nsinfo__mountns_exit(&nsc);
> if (fd < 0)
> return -errno;
>
> @@ -582,7 +597,7 @@ static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp,
> ret = -EINVAL;
> goto error;
> }
> - ret = get_text_start_address(tp->module, &stext);
> + ret = get_text_start_address(tp->module, &stext, NULL);
> if (ret < 0)
> goto error;
> addr += stext;
> @@ -659,7 +674,7 @@ post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
>
> /* Prepare a map for offline binary */
> map = dso__new_map(pathname);
> - if (!map || get_text_start_address(pathname, &stext) < 0) {
> + if (!map || get_text_start_address(pathname, &stext, NULL) < 0) {
> pr_warning("Failed to get ELF symbols for %s\n", pathname);
> return -EINVAL;
> }
> @@ -676,7 +691,8 @@ post_process_offline_probe_trace_events(struct probe_trace_event *tevs,
> }
>
> static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
> - int ntevs, const char *exec)
> + int ntevs, const char *exec,
> + struct nsinfo *nsi)
> {
> int i, ret = 0;
> unsigned long stext = 0;
> @@ -684,7 +700,7 @@ static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
> if (!exec)
> return 0;
>
> - ret = get_text_start_address(exec, &stext);
> + ret = get_text_start_address(exec, &stext, nsi);
> if (ret < 0)
> return ret;
>
> @@ -715,7 +731,7 @@ post_process_module_probe_trace_events(struct probe_trace_event *tevs,
> if (!module)
> return 0;
>
> - map = get_target_map(module, false);
> + map = get_target_map(module, NULL, false);
> if (!map || debuginfo__get_text_offset(dinfo, &text_offs, true) < 0) {
> pr_warning("Failed to get ELF symbols for %s\n", module);
> return -EINVAL;
> @@ -802,7 +818,8 @@ static int post_process_probe_trace_events(struct perf_probe_event *pev,
> int ret;
>
> if (uprobe)
> - ret = add_exec_to_probe_trace_events(tevs, ntevs, module);
> + ret = add_exec_to_probe_trace_events(tevs, ntevs, module,
> + pev->nsi);
> else if (module)
> /* Currently ref_reloc_sym based probe is not for drivers */
> ret = post_process_module_probe_trace_events(tevs, ntevs,
> @@ -825,7 +842,7 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
> struct debuginfo *dinfo;
> int ntevs, ret = 0;
>
> - dinfo = open_debuginfo(pev->target, !need_dwarf);
> + dinfo = open_debuginfo(pev->target, pev->nsi, !need_dwarf);
> if (!dinfo) {
> if (need_dwarf)
> return -ENOENT;
> @@ -945,7 +962,7 @@ static int __show_line_range(struct line_range *lr, const char *module,
> char sbuf[STRERR_BUFSIZE];
>
> /* Search a line range */
> - dinfo = open_debuginfo(module, false);
> + dinfo = open_debuginfo(module, NULL, false);
> if (!dinfo)
> return -ENOENT;
>
> @@ -1021,14 +1038,18 @@ static int __show_line_range(struct line_range *lr, const char *module,
> return ret;
> }
>
> -int show_line_range(struct line_range *lr, const char *module, bool user)
> +int show_line_range(struct line_range *lr, const char *module,
> + struct nsinfo *nsi, bool user)
> {
> int ret;
> + struct nscookie nsc;
>
> ret = init_probe_symbol_maps(user);
> if (ret < 0)
> return ret;
> + nsinfo__mountns_enter(nsi, &nsc);
> ret = __show_line_range(lr, module, user);
> + nsinfo__mountns_exit(&nsc);
> exit_probe_symbol_maps();
>
> return ret;
> @@ -1111,7 +1132,7 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs,
> if (ret < 0)
> return ret;
>
> - dinfo = open_debuginfo(pevs->target, false);
> + dinfo = open_debuginfo(pevs->target, pevs->nsi, false);
> if (!dinfo) {
> ret = -ENOENT;
> goto out;
> @@ -2703,6 +2724,7 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
> struct probe_trace_event *tev = NULL;
> struct probe_cache *cache = NULL;
> struct strlist *namelist[2] = {NULL, NULL};
> + struct nscookie nsc;
>
> up = pev->uprobes ? 1 : 0;
> fd[up] = __open_probe_file_and_namelist(up, &namelist[up]);
> @@ -2729,7 +2751,9 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
> if (ret < 0)
> break;
>
> + nsinfo__mountns_enter(pev->nsi, &nsc);
> ret = probe_file__add_event(fd[up], tev);
> + nsinfo__mountns_exit(&nsc);
> if (ret < 0)
> break;
>
> @@ -2805,7 +2829,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
> int ret, i, j, skipped = 0;
> char *mod_name;
>
> - map = get_target_map(pev->target, pev->uprobes);
> + map = get_target_map(pev->target, pev->nsi, pev->uprobes);
> if (!map) {
> ret = -EINVAL;
> goto out;
> @@ -3345,13 +3369,16 @@ int apply_perf_probe_events(struct perf_probe_event *pevs, int npevs)
> void cleanup_perf_probe_events(struct perf_probe_event *pevs, int npevs)
> {
> int i, j;
> + struct perf_probe_event *pev;
>
> /* Loop 3: cleanup and free trace events */
> for (i = 0; i < npevs; i++) {
> + pev = &pevs[i];
> for (j = 0; j < pevs[i].ntevs; j++)
> clear_probe_trace_event(&pevs[i].tevs[j]);
> zfree(&pevs[i].tevs);
> pevs[i].ntevs = 0;
> + nsinfo__zput(pev->nsi);
> clear_perf_probe_event(&pevs[i]);
> }
> }
> @@ -3409,8 +3436,8 @@ int del_perf_probe_events(struct strfilter *filter)
> return ret;
> }
>
> -int show_available_funcs(const char *target, struct strfilter *_filter,
> - bool user)
> +int show_available_funcs(const char *target, struct nsinfo *nsi,
> + struct strfilter *_filter, bool user)
> {
> struct rb_node *nd;
> struct map *map;
> @@ -3421,7 +3448,7 @@ int show_available_funcs(const char *target, struct strfilter *_filter,
> return ret;
>
> /* Get a symbol map */
> - map = get_target_map(target, user);
> + map = get_target_map(target, nsi, user);
> if (!map) {
> pr_err("Failed to get a map for %s\n", (target) ? : "kernel");
> return -EINVAL;
> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
> index 5812947..078681d 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -4,6 +4,7 @@
> #include <linux/compiler.h>
> #include <stdbool.h>
> #include "intlist.h"
> +#include "namespaces.h"
>
> /* Probe related configurations */
> struct probe_conf {
> @@ -92,6 +93,7 @@ struct perf_probe_event {
> struct perf_probe_arg *args; /* Arguments */
> struct probe_trace_event *tevs;
> int ntevs;
> + struct nsinfo *nsi; /* Target namespace */
> };
>
> /* Line range */
> @@ -163,10 +165,12 @@ int show_perf_probe_event(const char *group, const char *event,
> struct perf_probe_event *pev,
> const char *module, bool use_stdout);
> int show_perf_probe_events(struct strfilter *filter);
> -int show_line_range(struct line_range *lr, const char *module, bool user);
> +int show_line_range(struct line_range *lr, const char *module,
> + struct nsinfo *nsi, bool user);
> int show_available_vars(struct perf_probe_event *pevs, int npevs,
> struct strfilter *filter);
> -int show_available_funcs(const char *module, struct strfilter *filter, bool user);
> +int show_available_funcs(const char *module, struct nsinfo *nsi,
> + struct strfilter *filter, bool user);
> void arch__fix_tev_from_maps(struct perf_probe_event *pev,
> struct probe_trace_event *tev, struct map *map,
> struct symbol *sym);
> @@ -180,7 +184,7 @@ int e_snprintf(char *str, size_t size, const char *format, ...) __printf(3, 4);
> int copy_to_probe_trace_arg(struct probe_trace_arg *tvar,
> struct perf_probe_arg *pvar);
>
> -struct map *get_target_map(const char *target, bool user);
> +struct map *get_target_map(const char *target, struct nsinfo *nsi, bool user);
>
> void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
> int ntevs);
> --
> 2.7.4
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