On Tue, Aug 06, 2024 at 10:01:34AM +0800, David Gow wrote:
In commit 7d3c33b290b1 ("kunit: Device wrappers should also manage driver name"), the kunit_kstrdup_const() and kunit_kfree_const() were introduced as an optimisation of kunit_kstrdup(), which only copy/free strings from the kernel rodata.
However, these are inline functions, and is_kernel_rodata() only works for built-in code. This causes problems in two cases:
- If kunit is built as a module, __{start,end}_rodata is not defined.
- If a kunit test using these functions is built as a module, it will suffer the same fate.
Restrict the is_kernel_rodata() case to when KUnit is built as a module, which fixes the first case, at the cost of losing the optimisation.
Also, make kunit_{kstrdup,kfree}_const non-inline, so that other modules using them will not accidentally depend on is_kernel_rodata(). If KUnit is built-in, they'll benefit from the optimisation, if KUnit is not, they won't, but the string will be properly duplicated.
I wonder if this series should be refreshed: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/log/?h=devel/...
We gained is_kernel_rodata() and is_kernel_ro_after_init() since this original proposal, which is what the proposed core_kernel_rodata() checks.
It adds a is_module_rodata...() check, so with the is_kernel_*() checks, it's possible to do a check across the entire kernel and all modules.
-Kees
(And fix a couple of typos in the doc comment, too.)
Reported-by: Nico Pache npache@redhat.com Closes: https://lore.kernel.org/all/CAA1CXcDKht4vOL-acxrARbm6JhGna8_k8wjYJ-vHONink8a... Fixes: 7d3c33b290b1 ("kunit: Device wrappers should also manage driver name") Signed-off-by: David Gow davidgow@google.com
include/kunit/test.h | 16 +++------------- lib/kunit/test.c | 19 +++++++++++++++++++ 2 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h index da9e84de14c0..5ac237c949a0 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -489,11 +489,7 @@ static inline void *kunit_kcalloc(struct kunit *test, size_t n, size_t size, gfp
- Calls kunit_kfree() only if @x is not in .rodata section.
- See kunit_kstrdup_const() for more information.
*/ -static inline void kunit_kfree_const(struct kunit *test, const void *x) -{
- if (!is_kernel_rodata((unsigned long)x))
kunit_kfree(test, x);-} +void kunit_kfree_const(struct kunit *test, const void *x); /**
- kunit_kstrdup() - Duplicates a string into a test managed allocation.
@@ -527,16 +523,10 @@ static inline char *kunit_kstrdup(struct kunit *test, const char *str, gfp_t gfp
- @gfp: flags passed to underlying kmalloc().
- Calls kunit_kstrdup() only if @str is not in the rodata section. Must be freed with
- kunit_free_const() -- not kunit_free().
*/
- kunit_kfree_const() -- not kunit_kfree().
- See kstrdup_const() and kunit_kmalloc_array() for more information.
-static inline const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp) -{
- if (is_kernel_rodata((unsigned long)str))
return str;- return kunit_kstrdup(test, str, gfp);
-} +const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp); /**
- kunit_vm_mmap() - Allocate KUnit-tracked vm_mmap() area
diff --git a/lib/kunit/test.c b/lib/kunit/test.c index e8b1b52a19ab..089c832e3cdb 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -874,6 +874,25 @@ void kunit_kfree(struct kunit *test, const void *ptr) } EXPORT_SYMBOL_GPL(kunit_kfree); +void kunit_kfree_const(struct kunit *test, const void *x) +{ +#if !IS_MODULE(CONFIG_KUNIT)
- if (!is_kernel_rodata((unsigned long)x))
+#endif
kunit_kfree(test, x);+} +EXPORT_SYMBOL_GPL(kunit_kfree_const);
+const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp) +{ +#if !IS_MODULE(CONFIG_KUNIT)
- if (is_kernel_rodata((unsigned long)str))
return str;+#endif
- return kunit_kstrdup(test, str, gfp);
+} +EXPORT_SYMBOL_GPL(kunit_kstrdup_const);
void kunit_cleanup(struct kunit *test) { struct kunit_resource *res; -- 2.46.0.rc2.264.g509ed76dc8-goog