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 X-Spam-Level: X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3491C433DB for ; Fri, 12 Mar 2021 19:58:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60F4F64EF1 for ; Fri, 12 Mar 2021 19:58:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234491AbhCLT6V (ORCPT ); Fri, 12 Mar 2021 14:58:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:59574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232439AbhCLT6T (ORCPT ); Fri, 12 Mar 2021 14:58:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 208BC64F83; Fri, 12 Mar 2021 19:58:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615579099; bh=abbuICQ6vvYm6Em1eciR2crTv1YpzhEKMalP26l2qe0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HPAy7gy6iVv3+7gN0HPYidOlLWRsNL2o+QknK83mwuF8f/GxUttXTnBG4IMNINfgL KLxnv4bLEvLUqmOS+/pFujS+dizhrw7CsePBv567CoymKPvnAjkHh7TjoUHUjrVD3h lVUT8uANG7BVJR4x/b5k7wkUmoOoUCR8svDezIvhorVQf5WtzRKXJeBBGz7mgEWEfy ZUZafL9Z04h/h9D7w6SJsqek8O3IsFTVOQhpqSqL/11w6qhWRZ+Nk6kJFA79JHx0ib RUcUn1qCgvJ1KyKEP6N5+TGznTWMAbdkSzYTVGx5Br5OMD0tDaut82N6XdEE33P2nV lxo8jzcsCJZsg== Date: Fri, 12 Mar 2021 12:58:15 -0700 From: Nathan Chancellor To: Nick Desaulniers Cc: Peter Oberparleiter , Andrew Morton , Fangrui Song , Prasad Sodagudi , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH] gcov: fix clang-11+ support Message-ID: <20210312195815.2hnhuyk3qo4p7ysr@archlinux-ax161> References: <20210312192139.2503087-1-ndesaulniers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210312192139.2503087-1-ndesaulniers@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 12, 2021 at 11:21:39AM -0800, Nick Desaulniers wrote: > LLVM changed the expected function signatures for llvm_gcda_start_file() > and llvm_gcda_emit_function() in the clang-11 release. Users of clang-11 > or newer may have noticed their kernels failing to boot due to a panic > when enabling CONFIG_GCOV_KERNEL=y +CONFIG_GCOV_PROFILE_ALL=y. Fix up > the function signatures so calling these functions doesn't panic the > kernel. > > When we drop clang-10 support from the kernel, we should carefully > update the original implementations to try to preserve git blame, > deleting these implementations. > > Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 > Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 > Cc: Fangrui Song > Reported-by: Prasad Sodagudi > Signed-off-by: Nick Desaulniers I can reproduce the panic (as a boot hang) in QEMU before this patch and it is resolved after it so: Tested-by: Nathan Chancellor However, the duplication hurts :( would it potentially be better to just do the full update to clang-11+ and require it for CONFIG_GCOV_KERNEL? depends on CC_IS_GCC || CLANG_VERSION >= 110000? > --- > kernel/gcov/clang.c | 69 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 69 insertions(+) > > diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c > index c94b820a1b62..20e6760ec05d 100644 > --- a/kernel/gcov/clang.c > +++ b/kernel/gcov/clang.c > @@ -75,7 +75,9 @@ struct gcov_fn_info { > > u32 num_counters; > u64 *counters; > +#if __clang_major__ < 11 > const char *function_name; > +#endif > }; > > static struct gcov_info *current_info; > @@ -105,6 +107,7 @@ void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush) > } > EXPORT_SYMBOL(llvm_gcov_init); > > +#if __clang_major__ < 11 > void llvm_gcda_start_file(const char *orig_filename, const char version[4], > u32 checksum) > { > @@ -113,7 +116,17 @@ void llvm_gcda_start_file(const char *orig_filename, const char version[4], > current_info->checksum = checksum; > } > EXPORT_SYMBOL(llvm_gcda_start_file); > +#else > +void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum) > +{ > + current_info->filename = orig_filename; > + current_info->version = version; > + current_info->checksum = checksum; > +} > +EXPORT_SYMBOL(llvm_gcda_start_file); > +#endif > > +#if __clang_major__ < 11 > void llvm_gcda_emit_function(u32 ident, const char *function_name, > u32 func_checksum, u8 use_extra_checksum, u32 cfg_checksum) > { > @@ -133,6 +146,24 @@ void llvm_gcda_emit_function(u32 ident, const char *function_name, > list_add_tail(&info->head, ¤t_info->functions); > } > EXPORT_SYMBOL(llvm_gcda_emit_function); > +#else > +void llvm_gcda_emit_function(u32 ident, u32 func_checksum, > + u8 use_extra_checksum, u32 cfg_checksum) > +{ > + struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL); > + > + if (!info) > + return; > + > + INIT_LIST_HEAD(&info->head); > + info->ident = ident; > + info->checksum = func_checksum; > + info->use_extra_checksum = use_extra_checksum; > + info->cfg_checksum = cfg_checksum; > + list_add_tail(&info->head, ¤t_info->functions); > +} > +EXPORT_SYMBOL(llvm_gcda_emit_function); > +#endif > > void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters) > { > @@ -295,6 +326,7 @@ void gcov_info_add(struct gcov_info *dst, struct gcov_info *src) > } > } > > +#if __clang_major__ < 11 > static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn) > { > size_t cv_size; /* counter values size */ > @@ -322,6 +354,28 @@ static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn) > kfree(fn_dup); > return NULL; > } > +#else > +static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn) > +{ > + size_t cv_size; /* counter values size */ > + struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn), > + GFP_KERNEL); > + if (!fn_dup) > + return NULL; > + INIT_LIST_HEAD(&fn_dup->head); > + > + cv_size = fn->num_counters * sizeof(fn->counters[0]); > + fn_dup->counters = vmalloc(cv_size); > + if (!fn_dup->counters) { > + kfree(fn_dup); > + return NULL; > + } > + > + memcpy(fn_dup->counters, fn->counters, cv_size); > + > + return fn_dup; > +} > +#endif > > /** > * gcov_info_dup - duplicate profiling data set > @@ -362,6 +416,7 @@ struct gcov_info *gcov_info_dup(struct gcov_info *info) > * gcov_info_free - release memory for profiling data set duplicate > * @info: profiling data set duplicate to free > */ > +#if __clang_major__ < 11 > void gcov_info_free(struct gcov_info *info) > { > struct gcov_fn_info *fn, *tmp; > @@ -375,6 +430,20 @@ void gcov_info_free(struct gcov_info *info) > kfree(info->filename); > kfree(info); > } > +#else > +void gcov_info_free(struct gcov_info *info) > +{ > + struct gcov_fn_info *fn, *tmp; > + > + list_for_each_entry_safe(fn, tmp, &info->functions, head) { > + vfree(fn->counters); > + list_del(&fn->head); > + kfree(fn); > + } > + kfree(info->filename); > + kfree(info); > +} > +#endif > > #define ITER_STRIDE PAGE_SIZE > > > base-commit: f78d76e72a4671ea52d12752d92077788b4f5d50 > -- > 2.31.0.rc2.261.g7f71774620-goog >