Messages in this thread | | | Date | Fri, 18 Sep 2020 11:47:45 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH 2/2] perf probe: Fall back to debuginfod query if debuginfo and source not found |
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On Thu, 17 Sep 2020 21:40:22 -0300 Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> Em Thu, Sep 17, 2020 at 01:44:52AM +0900, Masami Hiramatsu escreveu: > > Since the perf-probe heavily depends on the debuginfo, debuginfod > > gives us many benefits on the perf probe command on remote machine. > > Especially, this will be helpful for the embedded devices which will > > not have enough storage, or boot with a cross-build kernel whose > > source code is in the host machine. > > This will work as similar to the commit c7a14fdcb3fa ("perf build-ids: > > Fall back to debuginfod query if debuginfo not found") > > > > Tested with: > > > > (host) $ cd PATH/TO/KBUILD/DIR/ > > (host) $ debuginfod -F . > > ... > > > > (remote) # perf probe -L vfs_read > > Failed to find the path for the kernel: No such file or directory > > Error: Failed to show lines. > > > > (remote) # export DEBUGINFOD_URLS="http://$HOST_IP:8002/" > > (remote) # perf probe -L vfs_read > > <vfs_read@...> > > 0 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) > > { > > 2 ssize_t ret; > > > > if (!(file->f_mode & FMODE_READ)) > > return -EBADF; > > 6 if (!(file->f_mode & FMODE_CAN_READ)) > > return -EINVAL; > > 8 if (unlikely(!access_ok(buf, count))) > > return -EFAULT; > > > > 11 ret = rw_verify_area(READ, file, pos, count); > > 12 if (ret) > > return ret; > > if (count > MAX_RW_COUNT) > > ... > > > > (remote) # perf probe -a "vfs_read count" > > Added new event: > > probe:vfs_read (on vfs_read with count) > > > > (remote) # perf probe -l > > probe:vfs_read (on vfs_read@ksrc/linux/fs/read_write.c with count) > > > > > > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> > > --- > > tools/perf/util/probe-event.c | 52 ++++++++++++++++++++++++++++++++++++- > > tools/perf/util/probe-finder.c | 56 ++++++++++++++++++++++++++++++++++++---- > > tools/perf/util/probe-finder.h | 7 ++++- > > 3 files changed, 107 insertions(+), 8 deletions(-) > > > > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c > > index 17831f186ab5..26733c8070a7 100644 > > --- a/tools/perf/util/probe-event.c > > +++ b/tools/perf/util/probe-event.c > > @@ -43,6 +43,10 @@ > > #include <linux/ctype.h> > > #include <linux/zalloc.h> > > > > +#ifdef HAVE_DEBUGINFOD_SUPPORT > > +#include <elfutils/debuginfod.h> > > +#endif > > + > > #define PERFPROBE_GROUP "probe" > > > > bool probe_event_dry_run; /* Dry run flag */ > > @@ -338,6 +342,8 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso) > > > > map = machine__kernel_map(host_machine); > > dso = map->dso; > > + if (!dso->has_build_id) > > + dso__read_running_kernel_build_id(dso, host_machine); > > > > vmlinux_name = symbol_conf.vmlinux_name; > > dso->load_errno = 0; > > @@ -453,6 +459,43 @@ static int get_alternative_line_range(struct debuginfo *dinfo, > > return ret; > > } > > > > +static struct debuginfo *open_from_debuginfod(struct dso *dso, struct nsinfo *nsi, > > + bool silent) > > +{ > > +#ifdef HAVE_DEBUGINFOD_SUPPORT > > Its better to have the whole function enclosed in the ifdef, to avoid: > > CC /tmp/build/perf/util/unwind-libunwind.o > util/probe-event.c: In function 'open_from_debuginfod': > util/probe-event.c:462:59: error: unused parameter 'dso' [-Werror=unused-parameter] > 462 | static struct debuginfo *open_from_debuginfod(struct dso *dso, struct nsinfo *nsi, > | ~~~~~~~~~~~~^~~ > util/probe-event.c:462:79: error: unused parameter 'nsi' [-Werror=unused-parameter] > 462 | static struct debuginfo *open_from_debuginfod(struct dso *dso, struct nsinfo *nsi, > | ~~~~~~~~~~~~~~~^~~ > util/probe-event.c:463:17: error: unused parameter 'silent' [-Werror=unused-parameter] > 463 | bool silent) > | ^ > CC /tmp/build/perf/util/zlib.o > util/probe-finder.c: In function 'get_source_from_debuginfod': > util/probe-finder.c:1988:51: error: unused parameter 'raw_path' [-Werror=unused-parameter] > 1988 | static int get_source_from_debuginfod(const char *raw_path, > | ~~~~~~~~~~~~^~~~~~~~ > util/probe-finder.c:1989:17: error: unused parameter 'sbuild_id' [-Werror=unused-parameter] > 1989 | const char *sbuild_id, char **new_path) > | ~~~~~~~~~~~~^~~~~~~~~ > util/probe-finder.c:1989:35: error: unused parameter 'new_path' [-Werror=unused-parameter] > 1989 | const char *sbuild_id, char **new_path) > | ~~~~~~~^~~~~~~~ > CC /tmp/build/perf/util/lzma.o > > > I.e. please test with: > > [acme@quaco perf]$ grep DEBUGINFOD tools/perf/Makefile.perf > # Define NO_LIBDEBUGINFOD if you do not want support debuginfod > [acme@quaco perf]$ >
Oops, right. I forgot to install libdebuginfod also on host side... Let me update the series.
Thank you,
> - Arnaldo > > > + debuginfod_client * c = debuginfod_begin(); > > + char sbuild_id[SBUILD_ID_SIZE + 1]; > > + struct debuginfo *ret = NULL; > > + struct nscookie nsc; > > + char *path; > > + int fd; > > + > > + if (!c) > > + return NULL; > > + > > + build_id__sprintf(dso->build_id, BUILD_ID_SIZE, sbuild_id); > > + fd = debuginfod_find_debuginfo(c, (const unsigned char *)sbuild_id, > > + 0, &path); > > + if (fd >= 0) > > + close(fd); > > + debuginfod_end(c); > > + if (fd < 0) { > > + if (!silent) > > + pr_debug("Failed to find debuginfo in debuginfod.\n"); > > + return NULL; > > + } > > + if (!silent) > > + pr_debug("Load debuginfo from debuginfod (%s)\n", path); > > + > > + nsinfo__mountns_enter(nsi, &nsc); > > + ret = debuginfo__new((const char *)path); > > + nsinfo__mountns_exit(&nsc); > > + return ret; > > +#else > > + return NULL; > > +#endif > > +} > > + > > /* Open new debuginfo of given module */ > > static struct debuginfo *open_debuginfo(const char *module, struct nsinfo *nsi, > > bool silent) > > @@ -472,6 +515,10 @@ static struct debuginfo *open_debuginfo(const char *module, struct nsinfo *nsi, > > strcpy(reason, "(unknown)"); > > } else > > dso__strerror_load(dso, reason, STRERR_BUFSIZE); > > + if (dso) > > + ret = open_from_debuginfod(dso, nsi, silent); > > + if (ret) > > + return ret; > > if (!silent) { > > if (module) > > pr_err("Module %s is not loaded, please specify its full path name.\n", module); > > @@ -959,6 +1006,7 @@ static int __show_line_range(struct line_range *lr, const char *module, > > int ret; > > char *tmp; > > char sbuf[STRERR_BUFSIZE]; > > + char sbuild_id[SBUILD_ID_SIZE] = ""; > > > > /* Search a line range */ > > dinfo = open_debuginfo(module, NULL, false); > > @@ -971,6 +1019,8 @@ static int __show_line_range(struct line_range *lr, const char *module, > > if (!ret) > > ret = debuginfo__find_line_range(dinfo, lr); > > } > > + if (dinfo->build_id) > > + build_id__sprintf(dinfo->build_id, BUILD_ID_SIZE, sbuild_id); > > debuginfo__delete(dinfo); > > if (ret == 0 || ret == -ENOENT) { > > pr_warning("Specified source line is not found.\n"); > > @@ -982,7 +1032,7 @@ static int __show_line_range(struct line_range *lr, const char *module, > > > > /* Convert source file path */ > > tmp = lr->path; > > - ret = get_real_path(tmp, lr->comp_dir, &lr->path); > > + ret = find_source_path(tmp, sbuild_id, lr->comp_dir, &lr->path); > > > > /* Free old path when new path is assigned */ > > if (tmp != lr->path) > > diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c > > index 659024342e9a..a98590940003 100644 > > --- a/tools/perf/util/probe-finder.c > > +++ b/tools/perf/util/probe-finder.c > > @@ -31,6 +31,10 @@ > > #include "probe-file.h" > > #include "string2.h" > > > > +#ifdef HAVE_DEBUGINFOD_SUPPORT > > +#include <elfutils/debuginfod.h> > > +#endif > > + > > /* Kprobe tracer basic type is up to u64 */ > > #define MAX_BASIC_TYPE_BITS 64 > > > > @@ -51,6 +55,7 @@ static const Dwfl_Callbacks offline_callbacks = { > > static int debuginfo__init_offline_dwarf(struct debuginfo *dbg, > > const char *path) > > { > > + GElf_Addr dummy; > > int fd; > > > > fd = open(path, O_RDONLY); > > @@ -70,6 +75,8 @@ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg, > > if (!dbg->dbg) > > goto error; > > > > + dwfl_module_build_id(dbg->mod, &dbg->build_id, &dummy); > > + > > dwfl_report_end(dbg->dwfl, NULL, NULL); > > > > return 0; > > @@ -942,6 +949,7 @@ static int probe_point_lazy_walker(const char *fname, int lineno, > > /* Find probe points from lazy pattern */ > > static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) > > { > > + char sbuild_id[SBUILD_ID_SIZE] = ""; > > int ret = 0; > > char *fpath; > > > > @@ -949,7 +957,10 @@ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) > > const char *comp_dir; > > > > comp_dir = cu_get_comp_dir(&pf->cu_die); > > - ret = get_real_path(pf->fname, comp_dir, &fpath); > > + if (pf->dbg->build_id) > > + build_id__sprintf(pf->dbg->build_id, > > + BUILD_ID_SIZE, sbuild_id); > > + ret = find_source_path(pf->fname, sbuild_id, comp_dir, &fpath); > > if (ret < 0) { > > pr_warning("Failed to find source file path.\n"); > > return ret; > > @@ -1448,7 +1459,7 @@ int debuginfo__find_trace_events(struct debuginfo *dbg, > > struct probe_trace_event **tevs) > > { > > struct trace_event_finder tf = { > > - .pf = {.pev = pev, .callback = add_probe_trace_event}, > > + .pf = {.pev = pev, .dbg = dbg, .callback = add_probe_trace_event}, > > .max_tevs = probe_conf.max_probes, .mod = dbg->mod}; > > int ret, i; > > > > @@ -1618,7 +1629,7 @@ int debuginfo__find_available_vars_at(struct debuginfo *dbg, > > struct variable_list **vls) > > { > > struct available_var_finder af = { > > - .pf = {.pev = pev, .callback = add_available_vars}, > > + .pf = {.pev = pev, .dbg = dbg, .callback = add_available_vars}, > > .mod = dbg->mod, > > .max_vls = probe_conf.max_probes}; > > int ret; > > @@ -1973,17 +1984,52 @@ int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr) > > return (ret < 0) ? ret : lf.found; > > } > > > > +/* debuginfod doesn't require the comp_dir but buildid is required */ > > +static int get_source_from_debuginfod(const char *raw_path, > > + const char *sbuild_id, char **new_path) > > +{ > > +#ifdef HAVE_DEBUGINFOD_SUPPORT > > + debuginfod_client * c = debuginfod_begin(); > > + const char *p = raw_path; > > + int fd; > > + > > + if (!c) > > + return -ENOMEM; > > + > > + fd = debuginfod_find_source(c, (const unsigned char *)sbuild_id, > > + 0, p, new_path); > > + pr_debug("Search %s from debuginfod -> %d\n", p, fd); > > + if (fd >= 0) > > + close(fd); > > + debuginfod_end(c); > > + if (fd < 0) { > > + pr_debug("Failed to find %s in debuginfod (%s)\n", > > + raw_path, sbuild_id); > > + return -ENOENT; > > + } > > + pr_debug("Got a source %s\n", *new_path); > > + > > + return 0; > > +#else > > + return -ENOTSUP; > > +#endif > > +} > > /* > > * Find a src file from a DWARF tag path. Prepend optional source path prefix > > * and chop off leading directories that do not exist. Result is passed back as > > * a newly allocated path on success. > > * Return 0 if file was found and readable, -errno otherwise. > > */ > > -int get_real_path(const char *raw_path, const char *comp_dir, > > - char **new_path) > > +int find_source_path(const char *raw_path, const char *sbuild_id, > > + const char *comp_dir, char **new_path) > > { > > const char *prefix = symbol_conf.source_prefix; > > > > + if (sbuild_id && !prefix) { > > + if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path)) > > + return 0; > > + } > > + > > if (!prefix) { > > if (raw_path[0] != '/' && comp_dir) > > /* If not an absolute path, try to use comp_dir */ > > diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h > > index 11be10080613..2febb5875678 100644 > > --- a/tools/perf/util/probe-finder.h > > +++ b/tools/perf/util/probe-finder.h > > @@ -4,6 +4,7 @@ > > > > #include <stdbool.h> > > #include "intlist.h" > > +#include "build-id.h" > > #include "probe-event.h" > > #include <linux/ctype.h> > > > > @@ -32,6 +33,7 @@ struct debuginfo { > > Dwfl_Module *mod; > > Dwfl *dwfl; > > Dwarf_Addr bias; > > + const unsigned char *build_id; > > }; > > > > /* This also tries to open distro debuginfo */ > > @@ -59,11 +61,12 @@ int debuginfo__find_available_vars_at(struct debuginfo *dbg, > > struct variable_list **vls); > > > > /* Find a src file from a DWARF tag path */ > > -int get_real_path(const char *raw_path, const char *comp_dir, > > - char **new_path); > > +int find_source_path(const char *raw_path, const char *sbuild_id, > > + const char *comp_dir, char **new_path); > > > > struct probe_finder { > > struct perf_probe_event *pev; /* Target probe event */ > > + struct debuginfo *dbg; > > > > /* Callback when a probe point is found */ > > int (*callback)(Dwarf_Die *sc_die, struct probe_finder *pf); > > > > -- > > - Arnaldo
-- Masami Hiramatsu <mhiramat@kernel.org>
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