Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755302AbdIGPAo (ORCPT ); Thu, 7 Sep 2017 11:00:44 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:37572 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742AbdIGPAl (ORCPT ); Thu, 7 Sep 2017 11:00:41 -0400 X-Google-Smtp-Source: ADKCNb7o0iWQrIo06jotNVRsOlibSYHcQWAGM1K9HyjXggOVjWyMJR8zQjoGo8beOHWHvOqJ7n1pmg== Date: Thu, 7 Sep 2017 23:58:53 +0900 From: Namhyung Kim To: Milian Wolff Cc: acme@kernel.org, Jin Yao , Linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , David Ahern , Peter Zijlstra , kernel-team@lge.com Subject: Re: [PATCH v2 03/14] perf report: create real callchain entries for inlined frames Message-ID: <20170907145853.GA5764@danjae.aot.lge.com> References: <20170806212446.24925-1-milian.wolff@kdab.com> <20170816075313.GA26397@sejong> <15340121.XrrsYTu5UN@agathebauer> <1935427.QE1zWV8lNS@agathebauer> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1935427.QE1zWV8lNS@agathebauer> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9289 Lines: 289 Hi Milian, On Wed, Sep 06, 2017 at 03:13:35PM +0200, Milian Wolff wrote: > On Sonntag, 20. August 2017 22:57:17 CEST Milian Wolff wrote: > > On Mittwoch, 16. August 2017 09:53:13 CEST Namhyung Kim wrote: > > > Hi Milian, > > > > > > On Sun, Aug 06, 2017 at 11:24:35PM +0200, Milian Wolff wrote: > > > > The inlined frames use a fake symbol that is tracked in a special > > > > map inside the dso, which is always sorted by name. All other > > > > > > It seems the above is not true. Fake symbols are maintained by > > > inline_node which in turn maintained by dso->inlines tree. > > > > OK, I'll rephrase this to make it more explicit. But what I call "map" is > > what you call "tree", no? > > > > > > > > > > @@ -201,7 +202,8 @@ static inline void callchain_cursor_reset(struct > > > > callchain_cursor *cursor)> > > > > > > > > int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip, > > > > > > > > struct map *map, struct symbol *sym, > > > > bool branch, struct branch_flags *flags, > > > > > > > > - int nr_loop_iter, int samples, u64 branch_from); > > > > + int nr_loop_iter, int samples, u64 branch_from, > > > > + const char *srcline); > > > > > > > > /* Close a cursor writing session. Initialize for the reader */ > > > > static inline void callchain_cursor_commit(struct callchain_cursor > > > > *cursor) > > > > > > I think it'd be better splitting srcline change into a separate > > > commit. > > > > OK, I'll try to see how this goes. It would simply add the boiler plate code > > to pass the srcline around, and then set it from within the callchain code, > > right? > > > > > > diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c > > > > index b9e087fb8247..72e6e390fd26 100644 > > > > --- a/tools/perf/util/dso.c > > > > +++ b/tools/perf/util/dso.c > > > > @@ -9,6 +9,7 @@ > > > > > > > > #include "compress.h" > > > > #include "path.h" > > > > #include "symbol.h" > > > > > > > > +#include "srcline.h" > > > > > > > > #include "dso.h" > > > > #include "machine.h" > > > > #include "auxtrace.h" > > > > > > > > @@ -1233,6 +1234,7 @@ void dso__delete(struct dso *dso) > > > > > > > > dso->long_name); > > > > > > > > for (i = 0; i < MAP__NR_TYPES; ++i) > > > > > > > > symbols__delete(&dso->symbols[i]); > > > > > > > > + inlines__tree_delete(&dso->inlined_nodes); > > > > > > Hmm.. inline_node is released after symbol but it seems to have a > > > problem. Please see below. > > > > > > > if (dso->short_name_allocated) { > > > > > > > > zfree((char **)&dso->short_name); > > > > > > > > diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h > > > > index f886141678eb..7d1e2b3c1f10 100644 > > > > --- a/tools/perf/util/dso.h > > > > +++ b/tools/perf/util/dso.h > > > > @@ -141,6 +141,7 @@ struct dso { > > > > > > > > struct rb_root *root; /* root of rbtree that rb_node is in > > > > */ > > > > > > struct rb_root symbols[MAP__NR_TYPES]; > > > > struct rb_root symbol_names[MAP__NR_TYPES]; > > > > > > > > + struct rb_root inlined_nodes; > > > > > > > > struct { > > > > > > > > u64 addr; > > > > struct symbol *symbol; > > > > > > [SNIP] > > > > > > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > > > > index d4df353051af..a7f8499c8756 100644 > > > > --- a/tools/perf/util/machine.c > > > > +++ b/tools/perf/util/machine.c > > > > diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c > > > > index ebc88a74e67b..a1fdf035d1dd 100644 > > > > --- a/tools/perf/util/srcline.c > > > > +++ b/tools/perf/util/srcline.c > > > > @@ -33,28 +33,17 @@ static const char *dso__name(struct dso *dso) > > > > > > > > return dso_name; > > > > > > > > } > > > > > > > > -static int inline_list__append(char *filename, char *funcname, int > > > > line_nr, - struct inline_node *node, struct dso *dso) > > > > +static int inline_list__append(struct symbol *symbol, char *srcline, > > > > + struct inline_node *node) > > > > > > > > { > > > > > > > > struct inline_list *ilist; > > > > > > > > - char *demangled; > > > > > > > > ilist = zalloc(sizeof(*ilist)); > > > > if (ilist == NULL) > > > > > > > > return -1; > > > > > > > > - ilist->filename = filename; > > > > - ilist->line_nr = line_nr; > > > > - > > > > - if (dso != NULL) { > > > > - demangled = dso__demangle_sym(dso, 0, funcname); > > > > - if (demangled == NULL) { > > > > - ilist->funcname = funcname; > > > > - } else { > > > > - ilist->funcname = demangled; > > > > - free(funcname); > > > > - } > > > > - } > > > > + ilist->symbol = symbol; > > > > + ilist->srcline = srcline; > > > > > > > > if (callchain_param.order == ORDER_CALLEE) > > > > > > > > list_add_tail(&ilist->list, &node->val); > > > > > > > > @@ -64,6 +53,30 @@ static int inline_list__append(char *filename, char > > > > *funcname, int line_nr,> > > > > > > > > return 0; > > > > > > > > } > > > > > > > > +// basename version that takes a const input string > > > > +static const char *gnu_basename(const char *path) > > > > +{ > > > > + const char *base = strrchr(path, '/'); > > > > + > > > > + return base ? base + 1 : path; > > > > +} > > > > + > > > > +static char *srcline_from_fileline(const char *file, unsigned int line) > > > > +{ > > > > + char *srcline; > > > > + > > > > + if (!file) > > > > + return NULL; > > > > + > > > > + if (!srcline_full_filename) > > > > + file = gnu_basename(file); > > > > + > > > > + if (asprintf(&srcline, "%s:%u", file, line) < 0) > > > > + return NULL; > > > > + > > > > + return srcline; > > > > +} > > > > + > > > > > > > > #ifdef HAVE_LIBBFD_SUPPORT > > > > > > > > /* > > > > > > > > @@ -203,19 +216,55 @@ static void addr2line_cleanup(struct a2l_data > > > > *a2l) > > > > > > > > #define MAX_INLINE_NEST 1024 > > > > > > > > +static struct symbol *new_inline_sym(struct dso *dso, > > > > + struct symbol *base_sym, > > > > + const char *funcname) > > > > +{ > > > > + struct symbol *inline_sym; > > > > + char *demangled = NULL; > > > > + > > > > + if (dso) { > > > > + demangled = dso__demangle_sym(dso, 0, funcname); > > > > + if (demangled) > > > > + funcname = demangled; > > > > + } > > > > + > > > > + if (strcmp(funcname, base_sym->name) == 0) { > > > > + // reuse the real, existing symbol > > > > + inline_sym = base_sym; > > > > > > So inline_node could refer the existing symbol. > > > > Yes, that does indeed seem to be an issue. I wonder why I'm not seeing any > > crashes or valgrind/ASAN reports though. I'll have to dig into this. > > > > > > + } else { > > > > + // create a fake symbol for the inline frame > > > > + inline_sym = symbol__new(base_sym ? base_sym->start : 0, > > > > + base_sym ? base_sym->end : 0, > > > > + base_sym ? base_sym->binding : 0, > > > > + funcname); > > > > + if (inline_sym) > > > > + inline_sym->inlined = 1; > > > > + } > > > > + > > > > + free(demangled); > > > > + > > > > + return inline_sym; > > > > +} > > > > + > > > > > > > > static int inline_list__append_dso_a2l(struct dso *dso, > > > > > > > > - struct inline_node *node) > > > > + struct inline_node *node, > > > > + struct symbol *sym) > > > > > > > > { > > > > > > > > struct a2l_data *a2l = dso->a2l; > > > > > > > > - char *funcname = a2l->funcname ? strdup(a2l->funcname) : NULL; > > > > - char *filename = a2l->filename ? strdup(a2l->filename) : NULL; > > > > + struct symbol *inline_sym = new_inline_sym(dso, sym, a2l->funcname); > > > > + char *srcline = NULL; > > > > + > > > > + if (a2l->filename) > > > > + srcline = srcline_from_fileline(a2l->filename, a2l->line); > > > > > > > > - return inline_list__append(filename, funcname, a2l->line, node, dso); > > > > + return inline_list__append(inline_sym, srcline, node); > > > > > > > > } > > > > > > [SNIP] > > > > > > > @@ -511,10 +563,63 @@ void inline_node__delete(struct inline_node *node) > > > > > > > > list_for_each_entry_safe(ilist, tmp, &node->val, list) { > > > > > > > > list_del_init(&ilist->list); > > > > > > > > - zfree(&ilist->filename); > > > > - zfree(&ilist->funcname); > > > > + zfree(&ilist->srcline); > > > > + // only the inlined symbols are owned by the list > > > > + if (ilist->symbol && ilist->symbol->inlined) > > > > + symbol__delete(ilist->symbol); > > > > > > Existing symbols are released at this moment. > > > > Thanks for the review, I'll try to look into these issues once I have more > > time again. > > OK, so I just dug into this part of the patch again. I don't think it's > actually a problem after all: > > When an inline node reuses the real symbol, that symbol won't have its > `inlined` member set to true. Thus these symbols will never get deleted by > inline_node__delete. But ilist->symbol is a dangling pointer so accessing ->inlined would be a problem, no? > If you have suggestions on how to make this clearer, I'm > all ears. For now, I'll add a comment to where we alias/reuse the symbol. > > I'll try to split up the patch now to make it somehow easier to review. Thanks for doing this, but I'm afraid I don't have time to review before going to OSS-NA. Thanks, Namhyung