From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3233C6FD1C for ; Mon, 13 Mar 2023 12:30:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229688AbjCMMaO (ORCPT ); Mon, 13 Mar 2023 08:30:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229593AbjCMMaM (ORCPT ); Mon, 13 Mar 2023 08:30:12 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF61162331 for ; Mon, 13 Mar 2023 05:30:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 323B961259 for ; Mon, 13 Mar 2023 12:30:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BAB3C4339C; Mon, 13 Mar 2023 12:30:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1678710602; bh=aidmjXqaw1iD1JIBMsTAXYt1UNmT8gIoURIk+QLUtyg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CK6F/LYxXphdtO9SE0XesE2Z2R6a6Hg7u9Kyt2uVYo3+qeiggUe20GPLE0UGmGE74 andQh1+hNuaah3WSnKxM87vKmlqK7bN97+o0xWAgtT80iHuuuoywkyUWqIIiN9EbGP P0yP5HZhl2xF1WRLENTV0MjMukpULYwF5HlYiQCKZ7rIrF1MxK/lxvP6JYedCmcepB IAbO4jboYMIHn72e2qRNLmXoer7NztimwKaj8iTFMphYgkNPQwbfD2hioKL/vfpC9H 1z1nLuaBp8zLy5sJ9zWMbB6hbbJGqq7Pq5YGbqd+XIb9ozBi3LvS3gT/cSpOHNvej+ jIZDb0h38mQNg== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id B2ECB4049F; Mon, 13 Mar 2023 09:29:59 -0300 (-03) Date: Mon, 13 Mar 2023 09:29:59 -0300 From: Arnaldo Carvalho de Melo To: Alan Maguire Cc: ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, haoluo@google.com, jolsa@kernel.org, john.fastabend@gmail.com, kpsingh@chromium.org, sinquersw@gmail.com, martin.lau@kernel.org, songliubraving@fb.com, sdf@google.com, timo@incline.eu, yhs@fb.com, bpf@vger.kernel.org Subject: Re: [PATCH dwarves 2/3] dwarves_fprintf: support skipping modifier Message-ID: References: <1678459850-16140-1-git-send-email-alan.maguire@oracle.com> <1678459850-16140-3-git-send-email-alan.maguire@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Em Mon, Mar 13, 2023 at 09:20:33AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Fri, Mar 10, 2023 at 02:50:49PM +0000, Alan Maguire escreveu: > > When doing BTF comparisons between functions defined in multiple > > CUs, it was noticed a few critical functions failed prototype > > comparisons due to multiple "const" modifiers; for example: > > > > function mismatch for 'memchr_inv'('memchr_inv'): 'void * ()(const const void * , int, size_t)' != 'void * ()(const void *, int, size_t)' > > > > function mismatch for 'strnlen'('strnlen'): '__kernel_size_t ()(const const char * , __kernel_size_t)' != '__kernel_size_t ()(const char *, size_t)' > > > > (note the "const const" in the first parameter.) > > > > As such it would be useful to omit modifiers for comparison > > purposes. Also noted was the fact that for the "no_parm_names" > > case, an extra space was being emitted in some cases, also > > throwing off string comparisons of prototypes. > > Running 'btfdiff vmlinux' after this change ends up in a segfault: > > ⬢[acme@toolbox pahole]$ btfdiff vmlinux > /var/home/acme/bin/btfdiff: line 34: 8183 Segmentation fault (core dumped) ${pahole_bin} -F dwarf --flat_arrays --sort --jobs --suppress_aligned_attribute --suppress_force_paddings --suppress_packed --lang_exclude rust --show_private_classes $dwarf_input > $dwarf_output > /var/home/acme/bin/btfdiff: line 39: 8237 Segmentation fault (core dumped) ${pahole_bin} -F btf --sort --suppress_aligned_attribute --suppress_packed $btf_input > $btf_output > ⬢[acme@toolbox pahole]$ > > Investigating. (gdb) run -F dwarf --flat_arrays --sort --jobs --suppress_aligned_attribute --suppress_force_paddings --suppress_packed --lang_exclude rust --show_private_classes vmlinux Starting program: /var/home/acme/bin/pahole -F dwarf --flat_arrays --sort --jobs --suppress_aligned_attribute --suppress_force_paddings --suppress_packed --lang_exclude rust --show_private_classes vmlinux Thread 1 "pahole" received signal SIGSEGV, Segmentation fault. 0x00007ffff7f26cff in __tag__name (tag=0x7fff88016a20, cu=0x7fff88001e30, bf=0x7fffffffce90 "void ()(void)", len=1024, conf=0x0) at /var/home/acme/git/pahole/dwarves_fprintf.c:584 584 if (!conf->skip_emitting_modifier) { (gdb) bt #0 0x00007ffff7f26cff in __tag__name (tag=0x7fff88016a20, cu=0x7fff88001e30, bf=0x7fffffffce90 "void ()(void)", len=1024, conf=0x0) at /var/home/acme/git/pahole/dwarves_fprintf.c:584 #1 0x00007ffff7f26873 in tag__ptr_name (tag=0x7fff88016990, cu=0x7fff88001e30, bf=0x7fffffffd9d0 "long unsigned int", len=1024, ptr_suffix=0x7ffff7f88fb0 "*", conf=0x0) at /var/home/acme/git/pahole/dwarves_fprintf.c:515 #2 0x00007ffff7f26acd in __tag__name (tag=0x7fff88016990, cu=0x7fff88001e30, bf=0x7fffffffd9d0 "long unsigned int", len=1024, conf=0x0) at /var/home/acme/git/pahole/dwarves_fprintf.c:551 #3 0x00007ffff7f270d5 in tag__name (tag=0x7fff88016990, cu=0x7fff88001e30, bf=0x7fffffffd9d0 "long unsigned int", len=1024, conf=0x0) at /var/home/acme/git/pahole/dwarves_fprintf.c:639 #4 0x0000000000404042 in type__compare_members_types (a=0x7fff9401bc30, cu_a=0x7fff94001e30, b=0x7fff8801bba0, cu_b=0x7fff88001e30) at /var/home/acme/git/pahole/pahole.c:258 #5 0x0000000000404cd0 in resort_add (resorted=0x7fffffffded8, str=0x7fff8801d120) at /var/home/acme/git/pahole/pahole.c:649 #6 0x0000000000404d7e in resort_classes (resorted=0x7fffffffded8, head=0x411420 ) at /var/home/acme/git/pahole/pahole.c:668 #7 0x0000000000404dda in print_ordered_classes () at /var/home/acme/git/pahole/pahole.c:678 #8 0x000000000040a93c in main (argc=13, argv=0x7fffffffe068) at /var/home/acme/git/pahole/pahole.c:3528 (gdb) I'm adding this: diff --git a/dwarves_fprintf.c b/dwarves_fprintf.c index b20a473125c3aa41..c2fdcdad078a5335 100644 --- a/dwarves_fprintf.c +++ b/dwarves_fprintf.c @@ -506,7 +506,7 @@ static const char *tag__ptr_name(const struct tag *tag, const struct cu *cu, struct tag *next_type = cu__type(cu, type->type); if (next_type && tag__is_pointer(next_type)) { - if (!conf->skip_emitting_modifier) + if (!(conf && conf->skip_emitting_modifier)) const_pointer = "const "; type = next_type; } @@ -581,7 +581,7 @@ static const char *__tag__name(const struct tag *tag, const struct cu *cu, *type_str = __tag__name(type, cu, tmpbf, sizeof(tmpbf), pconf); - if (!conf->skip_emitting_modifier) { + if (!pconf->skip_emitting_modifier) { switch (tag->tag) { case DW_TAG_volatile_type: prefix = "volatile "; break; case DW_TAG_const_type: prefix = "const"; break; @@ -590,7 +590,7 @@ static const char *__tag__name(const struct tag *tag, const struct cu *cu, } } snprintf(bf, len, "%s%s%s%s", prefix, type_str, suffix, - conf->no_parm_names ? "" : " "); + pconf->no_parm_names ? "" : " "); } break; case DW_TAG_array_type: With it: ⬢[acme@toolbox pahole]$ btfdiff vmlinux ⬢[acme@toolbox pahole]$ > - Arnaldo > > > Signed-off-by: Alan Maguire > > --- > > dwarves.h | 1 + > > dwarves_fprintf.c | 26 ++++++++++++++++---------- > > 2 files changed, 17 insertions(+), 10 deletions(-) > > > > diff --git a/dwarves.h b/dwarves.h > > index d04a36d..7a319d1 100644 > > --- a/dwarves.h > > +++ b/dwarves.h > > @@ -134,6 +134,7 @@ struct conf_fprintf { > > uint8_t strip_inline:1; > > uint8_t skip_emitting_atomic_typedefs:1; > > uint8_t skip_emitting_errors:1; > > + uint8_t skip_emitting_modifier:1; > > }; > > > > struct cus; > > diff --git a/dwarves_fprintf.c b/dwarves_fprintf.c > > index 5c6bf9c..b20a473 100644 > > --- a/dwarves_fprintf.c > > +++ b/dwarves_fprintf.c > > @@ -506,7 +506,8 @@ static const char *tag__ptr_name(const struct tag *tag, const struct cu *cu, > > struct tag *next_type = cu__type(cu, type->type); > > > > if (next_type && tag__is_pointer(next_type)) { > > - const_pointer = "const "; > > + if (!conf->skip_emitting_modifier) > > + const_pointer = "const "; > > type = next_type; > > } > > } > > @@ -580,13 +581,16 @@ static const char *__tag__name(const struct tag *tag, const struct cu *cu, > > *type_str = __tag__name(type, cu, tmpbf, > > sizeof(tmpbf), > > pconf); > > - switch (tag->tag) { > > - case DW_TAG_volatile_type: prefix = "volatile "; break; > > - case DW_TAG_const_type: prefix = "const "; break; > > - case DW_TAG_restrict_type: suffix = " restrict"; break; > > - case DW_TAG_atomic_type: prefix = "_Atomic "; break; > > + if (!conf->skip_emitting_modifier) { > > + switch (tag->tag) { > > + case DW_TAG_volatile_type: prefix = "volatile "; break; > > + case DW_TAG_const_type: prefix = "const"; break; > > + case DW_TAG_restrict_type: suffix = " restrict"; break; > > + case DW_TAG_atomic_type: prefix = "_Atomic "; break; > > + } > > } > > - snprintf(bf, len, "%s%s%s ", prefix, type_str, suffix); > > + snprintf(bf, len, "%s%s%s%s", prefix, type_str, suffix, > > + conf->no_parm_names ? "" : " "); > > } > > break; > > case DW_TAG_array_type: > > @@ -818,9 +822,11 @@ print_default: > > case DW_TAG_const_type: > > modifier = "const"; > > print_modifier: { > > - size_t modifier_printed = fprintf(fp, "%s ", modifier); > > - tconf.type_spacing -= modifier_printed; > > - printed += modifier_printed; > > + if (!conf->skip_emitting_modifier) { > > + size_t modifier_printed = fprintf(fp, "%s ", modifier); > > + tconf.type_spacing -= modifier_printed; > > + printed += modifier_printed; > > + } > > > > struct tag *ttype = cu__type(cu, type->type); > > if (ttype) { > > -- > > 1.8.3.1 > > > > -- > > - Arnaldo -- - Arnaldo