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
Cc: [email protected] #5.4+
Reported-by: Prasad Sodagudi <[email protected]>
Tested-by: Prasad Sodagudi <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
---
kernel/gcov/clang.c | 38 +++++++++++++++++++++++++++++++++-----
1 file changed, 33 insertions(+), 5 deletions(-)
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
index d41f5ecda9db..1747204541bf 100644
--- a/kernel/gcov/clang.c
+++ b/kernel/gcov/clang.c
@@ -69,7 +69,9 @@ struct gcov_fn_info {
u32 ident;
u32 checksum;
+#if CONFIG_CLANG_VERSION < 110000
u8 use_extra_checksum;
+#endif
u32 cfg_checksum;
u32 num_counters;
@@ -111,6 +113,7 @@ void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
}
EXPORT_SYMBOL(llvm_gcda_start_file);
+#if CONFIG_CLANG_VERSION < 110000
void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
u8 use_extra_checksum, u32 cfg_checksum)
{
@@ -126,6 +129,21 @@ void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
info->cfg_checksum = cfg_checksum;
list_add_tail(&info->head, ¤t_info->functions);
}
+#else
+void llvm_gcda_emit_function(u32 ident, u32 func_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->cfg_checksum = cfg_checksum;
+ list_add_tail(&info->head, ¤t_info->functions);
+}
+#endif
EXPORT_SYMBOL(llvm_gcda_emit_function);
void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
@@ -256,11 +274,16 @@ int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
!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);
}
@@ -378,17 +401,22 @@ size_t convert_to_gcda(char *buffer, struct gcov_info *info)
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);
--
2.31.1.295.g9ea45b61b8-goog
On Wed, Apr 07, 2021 at 11:54:55AM -0700, Nick Desaulniers wrote:
> 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
> Cc: [email protected] #5.4+
> Reported-by: Prasad Sodagudi <[email protected]>
> Tested-by: Prasad Sodagudi <[email protected]>
> Signed-off-by: Nick Desaulniers <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
> ---
> kernel/gcov/clang.c | 38 +++++++++++++++++++++++++++++++++-----
> 1 file changed, 33 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
> index d41f5ecda9db..1747204541bf 100644
> --- a/kernel/gcov/clang.c
> +++ b/kernel/gcov/clang.c
> @@ -69,7 +69,9 @@ struct gcov_fn_info {
>
> u32 ident;
> u32 checksum;
> +#if CONFIG_CLANG_VERSION < 110000
> u8 use_extra_checksum;
> +#endif
> u32 cfg_checksum;
>
> u32 num_counters;
> @@ -111,6 +113,7 @@ void llvm_gcda_start_file(const char *orig_filename, u32 version, u32 checksum)
> }
> EXPORT_SYMBOL(llvm_gcda_start_file);
>
> +#if CONFIG_CLANG_VERSION < 110000
> void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
> u8 use_extra_checksum, u32 cfg_checksum)
> {
> @@ -126,6 +129,21 @@ void llvm_gcda_emit_function(u32 ident, u32 func_checksum,
> info->cfg_checksum = cfg_checksum;
> list_add_tail(&info->head, ¤t_info->functions);
> }
> +#else
> +void llvm_gcda_emit_function(u32 ident, u32 func_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->cfg_checksum = cfg_checksum;
> + list_add_tail(&info->head, ¤t_info->functions);
> +}
> +#endif
> EXPORT_SYMBOL(llvm_gcda_emit_function);
>
> void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters)
> @@ -256,11 +274,16 @@ int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
> !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);
> }
> @@ -378,17 +401,22 @@ size_t convert_to_gcda(char *buffer, struct gcov_info *info)
>
> 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);
> --
> 2.31.1.295.g9ea45b61b8-goog
>
On Wed, Apr 7, 2021 at 2:21 PM Andrew Morton <[email protected]> wrote:
>
> On Wed, 7 Apr 2021 11:54:55 -0700 Nick Desaulniers <[email protected]> wrote:
>
> > 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.
>
> Which tree is this against? I'm seeing quite a lot of rejects against
> Linus's current.
Today's linux-next; the only recent changes to this single source file
since my last patches were:
commit b3c4e66c908b ("gcov: combine common code")
commit 17d0508a080d ("gcov: use kvmalloc()")
both have your sign off, so I assume those are in your tree?
--
Thanks,
~Nick Desaulniers
On Wed, 7 Apr 2021 11:54:55 -0700 Nick Desaulniers <[email protected]> wrote:
> 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.
Which tree is this against? I'm seeing quite a lot of rejects against
Linus's current.
On Wed, 7 Apr 2021 14:28:21 -0700 Nick Desaulniers <[email protected]> wrote:
> On Wed, Apr 7, 2021 at 2:21 PM Andrew Morton <[email protected]> wrote:
> >
> > On Wed, 7 Apr 2021 11:54:55 -0700 Nick Desaulniers <[email protected]> wrote:
> >
> > > 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.
> >
> > Which tree is this against? I'm seeing quite a lot of rejects against
> > Linus's current.
>
> Today's linux-next; the only recent changes to this single source file
> since my last patches were:
>
> commit b3c4e66c908b ("gcov: combine common code")
> commit 17d0508a080d ("gcov: use kvmalloc()")
>
> both have your sign off, so I assume those are in your tree?
Yes, I presently have
gcov-clang-drop-support-for-clang-10-and-older.patch
gcov-combine-common-code.patch
gcov-simplify-buffer-allocation.patch
gcov-use-kvmalloc.patch
But this patch ("gcov: re-fix clang-11+ support") has cc:stable, so it
should be against Linus's tree, to give the -stable trees something
more mergeable.
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
Cc: [email protected] #5.4+
Reported-by: Prasad Sodagudi <[email protected]>
Tested-by: Prasad Sodagudi <[email protected]>
Signed-off-by: Nick Desaulniers <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
---
Changes V1 -> V2:
* Carried Nathan's reviewed-by tag.
* Rebased on mainline, as per Andrew.
* Left off patch 2/2 from the series
https://lore.kernel.org/lkml/[email protected]/
I assume that dropping support for clang-10+GCOV will be held
separately for -next for 5.13, while this will be sent for 5.12?
kernel/gcov/clang.c | 29 +++++++++++++++++++----------
1 file changed, 19 insertions(+), 10 deletions(-)
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c
index 8743150db2ac..c466c7fbdece 100644
--- a/kernel/gcov/clang.c
+++ b/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, 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)
+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, u32 func_checksum,
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_info *info1, struct gcov_info *info2)
!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 *buffer, struct gcov_info *info)
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);
base-commit: 3fb4f979b4fa1f92a02b538ae86e725b73e703d0
--
2.31.1.295.g9ea45b61b8-goog