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.
Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 Cc: stable@vger.kernel.org # 5.4 Reported-by: Prasad Sodagudi psodagud@quicinc.com Suggested-by: Nathan Chancellor nathan@kernel.org Reviewed-by: Fangrui Song maskray@google.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Tested-by: Nathan Chancellor nathan@kernel.org --- Changes V1 -> V2: * Use CONFIG_CLANG_VERSION instead of __clang_major__. * Pick up and retain Suggested-by, Tested-by, and Reviewed-by tags. * Drop note from commit message about `git blame`; I did what was sugguested in V1, but it still looks to git like I wrote those functions. Oh well.
kernel/gcov/clang.c | 69 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+)
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c index c94b820a1b62..8743150db2ac 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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
On 12.03.2021 23:41, 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.
Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 Cc: stable@vger.kernel.org # 5.4 Reported-by: Prasad Sodagudi psodagud@quicinc.com Suggested-by: Nathan Chancellor nathan@kernel.org Reviewed-by: Fangrui Song maskray@google.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Tested-by: Nathan Chancellor nathan@kernel.org
Looks good to me (minus the code duplication - but that's IMO acceptable since it's cleaned up again with patch 2).
Acked-by: Peter Oberparleiter oberpar@linux.ibm.com
That said, I'm currently thinking of adding a compile time check that performs a dry-run gcov_info => gcda conversion in user space to detect these kind of issues before kernels fail unpredictably [1]. I'm confident that this could work for the GCC gcov kernel code, not sure about the Clang version though. But if it's possible I guess it would make sense to extend this to include the Clang code as well.
Note that this check wouldn't work for cross-compiles since the build machine must be able to run code for the target machine.
[1] https://lore.kernel.org/lkml/1c7a49e7-0e27-561b-a2f9-d42a83dc4c29@linux.ibm....
Regards, Peter
On Fri, Mar 12, 2021 at 02:41:31PM -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.
Link: https://reviews.llvm.org/rGcdd683b516d147925212724b09ec6fb792a40041 Link: https://reviews.llvm.org/rG13a633b438b6500ecad9e4f936ebadf3411d0f44 Cc: stable@vger.kernel.org # 5.4 Reported-by: Prasad Sodagudi psodagud@quicinc.com Suggested-by: Nathan Chancellor nathan@kernel.org Reviewed-by: Fangrui Song maskray@google.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Tested-by: Nathan Chancellor nathan@kernel.org
Reviewed-by: Nathan Chancellor nathan@kernel.org
Changes V1 -> V2:
- Use CONFIG_CLANG_VERSION instead of __clang_major__.
- Pick up and retain Suggested-by, Tested-by, and Reviewed-by tags.
- Drop note from commit message about `git blame`; I did what was sugguested in V1, but it still looks to git like I wrote those functions. Oh well.
kernel/gcov/clang.c | 69 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+)
diff --git a/kernel/gcov/clang.c b/kernel/gcov/clang.c index c94b820a1b62..8743150db2ac 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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 CONFIG_CLANG_VERSION < 110000 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
linux-stable-mirror@lists.linaro.org
-
Nathan Chancellor -
Nick Desaulniers -
Peter Oberparleiter