This is a note to let you know that I've just added the patch titled
selftests/bpf: fix to avoid __msg tag de-duplication by clang
to the 6.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selftests-bpf-fix-to-avoid-__msg-tag-de-duplication-.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 91f0f57baea9745e781dd76fa675a6def4485458
Author: Eduard Zingerman <eddyz87@xxxxxxxxx>
Date: Tue Aug 20 03:23:51 2024 -0700
selftests/bpf: fix to avoid __msg tag de-duplication by clang
[ Upstream commit f00bb757ed630affc951691ddaff206039cbb7ee ]
__msg, __regex and __xlated tags are based on
__attribute__((btf_decl_tag("..."))) annotations.
Clang de-duplicates such annotations, e.g. the following
two sequences of tags are identical in final BTF:
/* seq A */ /* seq B */
__tag("foo") __tag("foo")
__tag("bar") __tag("bar")
__tag("foo")
Fix this by adding a unique suffix for each tag using __COUNTER__
pre-processor macro. E.g. here is a new definition for __msg:
#define __msg(msg) \
__attribute__((btf_decl_tag("comment:test_expect_msg=" XSTR(__COUNTER__) "=" msg)))
Using this definition the "seq A" from example above is translated to
BTF as follows:
[..] DECL_TAG 'comment:test_expect_msg=0=foo' type_id=X component_idx=-1
[..] DECL_TAG 'comment:test_expect_msg=1=bar' type_id=X component_idx=-1
[..] DECL_TAG 'comment:test_expect_msg=2=foo' type_id=X component_idx=-1
Surprisingly, this bug affects a single existing test:
verifier_spill_fill/old_stack_misc_vs_cur_ctx_ptr,
where sequence of identical messages was expected in the log.
Fixes: 537c3f66eac1 ("selftests/bpf: add generic BPF program tester-loader")
Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240820102357.3372779-4-eddyz87@xxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h
index 078268a19b773..20541a7cd8070 100644
--- a/tools/testing/selftests/bpf/progs/bpf_misc.h
+++ b/tools/testing/selftests/bpf/progs/bpf_misc.h
@@ -2,6 +2,9 @@
#ifndef __BPF_MISC_H__
#define __BPF_MISC_H__
+#define XSTR(s) STR(s)
+#define STR(s) #s
+
/* This set of attributes controls behavior of the
* test_loader.c:test_loader__run_subtests().
*
@@ -68,15 +71,15 @@
* Several __arch_* annotations could be specified at once.
* When test case is not run on current arch it is marked as skipped.
*/
-#define __msg(msg) __attribute__((btf_decl_tag("comment:test_expect_msg=" msg)))
-#define __regex(regex) __attribute__((btf_decl_tag("comment:test_expect_regex=" regex)))
-#define __xlated(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated=" msg)))
+#define __msg(msg) __attribute__((btf_decl_tag("comment:test_expect_msg=" XSTR(__COUNTER__) "=" msg)))
+#define __regex(regex) __attribute__((btf_decl_tag("comment:test_expect_regex=" XSTR(__COUNTER__) "=" regex)))
+#define __xlated(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated=" XSTR(__COUNTER__) "=" msg)))
#define __failure __attribute__((btf_decl_tag("comment:test_expect_failure")))
#define __success __attribute__((btf_decl_tag("comment:test_expect_success")))
#define __description(desc) __attribute__((btf_decl_tag("comment:test_description=" desc)))
-#define __msg_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_msg_unpriv=" msg)))
-#define __regex_unpriv(regex) __attribute__((btf_decl_tag("comment:test_expect_regex_unpriv=" regex)))
-#define __xlated_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated_unpriv=" msg)))
+#define __msg_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_msg_unpriv=" XSTR(__COUNTER__) "=" msg)))
+#define __regex_unpriv(regex) __attribute__((btf_decl_tag("comment:test_expect_regex_unpriv=" XSTR(__COUNTER__) "=" regex)))
+#define __xlated_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated_unpriv=" XSTR(__COUNTER__) "=" msg)))
#define __failure_unpriv __attribute__((btf_decl_tag("comment:test_expect_failure_unpriv")))
#define __success_unpriv __attribute__((btf_decl_tag("comment:test_expect_success_unpriv")))
#define __log_level(lvl) __attribute__((btf_decl_tag("comment:test_log_level="#lvl)))
diff --git a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
index 85e48069c9e61..d4b99c3b4719b 100644
--- a/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
+++ b/tools/testing/selftests/bpf/progs/verifier_spill_fill.c
@@ -1213,10 +1213,10 @@ __success __log_level(2)
* - once for path entry - label 2;
* - once for path entry - label 1 - label 2.
*/
-__msg("r1 = *(u64 *)(r10 -8)")
-__msg("exit")
-__msg("r1 = *(u64 *)(r10 -8)")
-__msg("exit")
+__msg("8: (79) r1 = *(u64 *)(r10 -8)")
+__msg("9: (95) exit")
+__msg("from 2 to 7")
+__msg("8: safe")
__msg("processed 11 insns")
__flag(BPF_F_TEST_STATE_FREQ)
__naked void old_stack_misc_vs_cur_ctx_ptr(void)
diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c
index 12b0c41e8d64c..0f59bc33a666c 100644
--- a/tools/testing/selftests/bpf/test_loader.c
+++ b/tools/testing/selftests/bpf/test_loader.c
@@ -215,6 +215,35 @@ static void update_flags(int *flags, int flag, bool clear)
*flags |= flag;
}
+/* Matches a string of form '<pfx>[^=]=.*' and returns it's suffix.
+ * Used to parse btf_decl_tag values.
+ * Such values require unique prefix because compiler does not add
+ * same __attribute__((btf_decl_tag(...))) twice.
+ * Test suite uses two-component tags for such cases:
+ *
+ * <pfx> __COUNTER__ '='
+ *
+ * For example, two consecutive __msg tags '__msg("foo") __msg("foo")'
+ * would be encoded as:
+ *
+ * [18] DECL_TAG 'comment:test_expect_msg=0=foo' type_id=15 component_idx=-1
+ * [19] DECL_TAG 'comment:test_expect_msg=1=foo' type_id=15 component_idx=-1
+ *
+ * And the purpose of this function is to extract 'foo' from the above.
+ */
+static const char *skip_dynamic_pfx(const char *s, const char *pfx)
+{
+ const char *msg;
+
+ if (strncmp(s, pfx, strlen(pfx)) != 0)
+ return NULL;
+ msg = s + strlen(pfx);
+ msg = strchr(msg, '=');
+ if (!msg)
+ return NULL;
+ return msg + 1;
+}
+
enum arch {
ARCH_X86_64 = 0x1,
ARCH_ARM64 = 0x2,
@@ -290,38 +319,32 @@ static int parse_test_spec(struct test_loader *tester,
} else if (strcmp(s, TEST_TAG_AUXILIARY_UNPRIV) == 0) {
spec->auxiliary = true;
spec->mode_mask |= UNPRIV;
- } else if (str_has_pfx(s, TEST_TAG_EXPECT_MSG_PFX)) {
- msg = s + sizeof(TEST_TAG_EXPECT_MSG_PFX) - 1;
+ } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_MSG_PFX))) {
err = push_msg(msg, NULL, &spec->priv.expect_msgs);
if (err)
goto cleanup;
spec->mode_mask |= PRIV;
- } else if (str_has_pfx(s, TEST_TAG_EXPECT_MSG_PFX_UNPRIV)) {
- msg = s + sizeof(TEST_TAG_EXPECT_MSG_PFX_UNPRIV) - 1;
+ } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_MSG_PFX_UNPRIV))) {
err = push_msg(msg, NULL, &spec->unpriv.expect_msgs);
if (err)
goto cleanup;
spec->mode_mask |= UNPRIV;
- } else if (str_has_pfx(s, TEST_TAG_EXPECT_REGEX_PFX)) {
- msg = s + sizeof(TEST_TAG_EXPECT_REGEX_PFX) - 1;
+ } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_REGEX_PFX))) {
err = push_msg(NULL, msg, &spec->priv.expect_msgs);
if (err)
goto cleanup;
spec->mode_mask |= PRIV;
- } else if (str_has_pfx(s, TEST_TAG_EXPECT_REGEX_PFX_UNPRIV)) {
- msg = s + sizeof(TEST_TAG_EXPECT_REGEX_PFX_UNPRIV) - 1;
+ } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_REGEX_PFX_UNPRIV))) {
err = push_msg(NULL, msg, &spec->unpriv.expect_msgs);
if (err)
goto cleanup;
spec->mode_mask |= UNPRIV;
- } else if (str_has_pfx(s, TEST_TAG_EXPECT_XLATED_PFX)) {
- msg = s + sizeof(TEST_TAG_EXPECT_XLATED_PFX) - 1;
+ } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_XLATED_PFX))) {
err = push_msg(msg, NULL, &spec->priv.expect_xlated);
if (err)
goto cleanup;
spec->mode_mask |= PRIV;
- } else if (str_has_pfx(s, TEST_TAG_EXPECT_XLATED_PFX_UNPRIV)) {
- msg = s + sizeof(TEST_TAG_EXPECT_XLATED_PFX_UNPRIV) - 1;
+ } else if ((msg = skip_dynamic_pfx(s, TEST_TAG_EXPECT_XLATED_PFX_UNPRIV))) {
err = push_msg(msg, NULL, &spec->unpriv.expect_xlated);
if (err)
goto cleanup;
