[PATCH v2] kcsan: test: don't put the expect array on the stack

From: Max Filippov
Date: Fri Dec 30 2022 - 19:45:30 EST


Size of the 'expect' array in the __report_matches is 1536 bytes, which
is exactly the default frame size warning limit of the xtensa
architecture.
As a result allmodconfig xtensa kernel builds with the gcc that does not
support the compiler plugins (which otherwise would push the said
warning limit to 2K) fail with the following message:

kernel/kcsan/kcsan_test.c:257:1: error: the frame size of 1680 bytes
is larger than 1536 bytes

Fix it by dynamically alocating the 'expect' array.

Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
---
Changes v1->v2:
- add WARN_ON in case of kmalloc failure

kernel/kcsan/kcsan_test.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
index dcec1b743c69..a60c561724be 100644
--- a/kernel/kcsan/kcsan_test.c
+++ b/kernel/kcsan/kcsan_test.c
@@ -159,7 +159,7 @@ static bool __report_matches(const struct expect_report *r)
const bool is_assert = (r->access[0].type | r->access[1].type) & KCSAN_ACCESS_ASSERT;
bool ret = false;
unsigned long flags;
- typeof(observed.lines) expect;
+ typeof(*observed.lines) *expect;
const char *end;
char *cur;
int i;
@@ -168,6 +168,10 @@ static bool __report_matches(const struct expect_report *r)
if (!report_available())
return false;

+ expect = kmalloc(sizeof(observed.lines), GFP_KERNEL);
+ if (WARN_ON(!expect))
+ return false;
+
/* Generate expected report contents. */

/* Title */
@@ -253,6 +257,7 @@ static bool __report_matches(const struct expect_report *r)
strstr(observed.lines[2], expect[1])));
out:
spin_unlock_irqrestore(&observed.lock, flags);
+ kfree(expect);
return ret;
}

--
2.30.2