From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, linux-mm@kvack.org,
mm-commits@vger.kernel.org, nathan@kernel.org,
ndesaulniers@google.com, psodagud@quicinc.com,
stable@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 09/16] gcov: re-fix clang-11+ support
Date: Fri, 09 Apr 2021 13:27:26 -0700 [thread overview]
Message-ID: <20210409202726.UGh0KJFgU%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210409132633.6855fc8fea1b3905ea1bb4be@linux-foundation.org>
From: Nick Desaulniers <ndesaulniers@google.com>
Subject: gcov: re-fix clang-11+ support
LLVM changed the expected function signature for llvm_gcda_emit_function()
in the clang-11 release. Users of clang-11 or newer may have noticed
their kernels producing invalid coverage information:
$ llvm-cov gcov -a -c -u -f -b <input>.gcda -- gcno=<input>.gcno
1 <func>: checksum mismatch, \
(<lineno chksum A>, <cfg chksum B>) != (<lineno chksum A>, <cfg chksum C>)
2 Invalid .gcda File!
...
Fix up the function signatures so calling this function interprets its
parameters correctly and computes the correct cfg checksum. In
particular, in clang-11, the additional checksum is no longer optional.
Link: https://reviews.llvm.org/rG25544ce2df0daa4304c07e64b9c8b0f7df60c11d
Link: https://lkml.kernel.org/r/20210408184631.1156669-1-ndesaulniers@google.com
Reported-by: Prasad Sodagudi <psodagud@quicinc.com>
Tested-by: Prasad Sodagudi <psodagud@quicinc.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Cc: <stable@vger.kernel.org> [5.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
kernel/gcov/clang.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)
--- a/kernel/gcov/clang.c~gcov-re-fix-clang-11-support
+++ a/kernel/gcov/clang.c
@@ -70,7 +70,9 @@ struct gcov_fn_info {
u32 ident;
u32 checksum;
+#if CONFIG_CLANG_VERSION < 110000
u8 use_extra_checksum;
+#endif
u32 cfg_checksum;
u32 num_counters;
@@ -145,10 +147,8 @@ void llvm_gcda_emit_function(u32 ident,
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)
+void llvm_gcda_emit_function(u32 ident, u32 func_checksum, u32 cfg_checksum)
{
struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL);
@@ -158,12 +158,11 @@ void llvm_gcda_emit_function(u32 ident,
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
+EXPORT_SYMBOL(llvm_gcda_emit_function);
void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
{
@@ -293,11 +292,16 @@ int gcov_info_is_compatible(struct gcov_
!list_is_last(&fn_ptr2->head, &info2->functions)) {
if (fn_ptr1->checksum != fn_ptr2->checksum)
return false;
+#if CONFIG_CLANG_VERSION < 110000
if (fn_ptr1->use_extra_checksum != fn_ptr2->use_extra_checksum)
return false;
if (fn_ptr1->use_extra_checksum &&
fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
return false;
+#else
+ if (fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum)
+ return false;
+#endif
fn_ptr1 = list_next_entry(fn_ptr1, head);
fn_ptr2 = list_next_entry(fn_ptr2, head);
}
@@ -529,17 +533,22 @@ static size_t convert_to_gcda(char *buff
list_for_each_entry(fi_ptr, &info->functions, head) {
u32 i;
- u32 len = 2;
-
- if (fi_ptr->use_extra_checksum)
- len++;
pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
- pos += store_gcov_u32(buffer, pos, len);
+#if CONFIG_CLANG_VERSION < 110000
+ pos += store_gcov_u32(buffer, pos,
+ fi_ptr->use_extra_checksum ? 3 : 2);
+#else
+ pos += store_gcov_u32(buffer, pos, 3);
+#endif
pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
pos += store_gcov_u32(buffer, pos, fi_ptr->checksum);
+#if CONFIG_CLANG_VERSION < 110000
if (fi_ptr->use_extra_checksum)
pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
+#else
+ pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
+#endif
pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE);
pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2);
_
next prev parent reply other threads:[~2021-04-09 20:27 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 20:26 incoming Andrew Morton
2021-04-09 20:27 ` [patch 01/16] MAINTAINERS: update CZ.NIC's Turris information Andrew Morton
2021-04-09 20:27 ` [patch 02/16] treewide: change my e-mail address, fix my name Andrew Morton
2021-04-09 20:27 ` [patch 03/16] mailmap: update email address for Jordan Crouse Andrew Morton
2021-04-09 20:27 ` [patch 04/16] .mailmap: fix old email addresses Andrew Morton
2021-04-09 20:27 ` [patch 05/16] kasan: fix hwasan build for gcc Andrew Morton
2021-04-09 20:39 ` Andrey Konovalov
2021-04-09 20:58 ` Andrew Morton
2021-04-12 9:56 ` Marco Elver
2021-04-12 12:54 ` Andrey Konovalov
2021-04-09 21:55 ` Linus Torvalds
2021-04-09 20:27 ` [patch 06/16] kasan: remove redundant config option Andrew Morton
2021-04-09 20:27 ` [patch 07/16] mm/gup: check page posion status for coredump Andrew Morton
2021-04-09 20:27 ` [patch 08/16] nds32: flush_dcache_page: use page_mapping_file to avoid races with swapoff Andrew Morton
2021-04-09 20:27 ` Andrew Morton [this message]
2021-04-09 20:27 ` [patch 10/16] ocfs2: fix deadlock between setattr and dio_end_io_write Andrew Morton
2021-04-09 20:27 ` [patch 11/16] ia64: fix user_stack_pointer() for ptrace() Andrew Morton
2021-04-09 20:27 ` [patch 12/16] fs: direct-io: fix missing sdio->boundary Andrew Morton
2021-04-09 20:27 ` [patch 13/16] kasan: fix conflict with page poisoning Andrew Morton
2021-04-09 20:27 ` [patch 14/16] lib/test_kasan_module.c: suppress unused var warning Andrew Morton
2021-04-09 20:27 ` [patch 15/16] kfence, x86: fix preemptible warning on KPTI-enabled systems Andrew Morton
2021-04-09 20:27 ` [patch 16/16] lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS Andrew Morton
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