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From: Nathan Chancellor <nathan@kernel.org>
To: Maxim Levitsky <maximlevitsky@gmail.com>,
	Alex Dubov <oakad@yahoo.com>,
	 Ulf Hansson <ulf.hansson@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
	linux-mmc@vger.kernel.org,  llvm@lists.linux.dev,
	patches@lists.linux.dev, stable@vger.kernel.org,
	 Nathan Chancellor <nathan@kernel.org>
Subject: [PATCH] memstick: core: Zero initialize id_reg in h_memstick_read_dev_id()
Date: Tue, 15 Jul 2025 15:56:05 -0700	[thread overview]
Message-ID: <20250715-memstick-fix-uninit-const-pointer-v1-1-f6753829c27a@kernel.org> (raw)

A new warning in clang [1] points out that id_reg is uninitialized then
passed to memstick_init_req() as a const pointer:

  drivers/memstick/core/memstick.c:330:59: error: variable 'id_reg' is uninitialized when passed as a const pointer argument here [-Werror,-Wuninitialized-const-pointer]
    330 |                 memstick_init_req(&card->current_mrq, MS_TPC_READ_REG, &id_reg,
        |                                                                         ^~~~~~

Commit de182cc8e882 ("drivers/memstick/core/memstick.c: avoid -Wnonnull
warning") intentionally passed this variable uninitialized to avoid an
-Wnonnull warning from a NULL value that was previously there because
id_reg is never read from the call to memstick_init_req() in
h_memstick_read_dev_id(). Just zero initialize id_reg to avoid the
warning, which is likely happening in the majority of builds using
modern compilers that support '-ftrivial-auto-var-init=zero'.

Cc: stable@vger.kernel.org
Fixes: de182cc8e882 ("drivers/memstick/core/memstick.c: avoid -Wnonnull warning")
Link: https://github.com/llvm/llvm-project/commit/00dacf8c22f065cb52efb14cd091d441f19b319e [1]
Closes: https://github.com/ClangBuiltLinux/linux/issues/2105
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/memstick/core/memstick.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c
index 043b9ec756ff..7f3f47db4c98 100644
--- a/drivers/memstick/core/memstick.c
+++ b/drivers/memstick/core/memstick.c
@@ -324,7 +324,7 @@ EXPORT_SYMBOL(memstick_init_req);
 static int h_memstick_read_dev_id(struct memstick_dev *card,
 				  struct memstick_request **mrq)
 {
-	struct ms_id_register id_reg;
+	struct ms_id_register id_reg = {};
 
 	if (!(*mrq)) {
 		memstick_init_req(&card->current_mrq, MS_TPC_READ_REG, &id_reg,

---
base-commit: ff09b71bf9daeca4f21d6e5e449641c9fad75b53
change-id: 20250715-memstick-fix-uninit-const-pointer-ed6f138bf40d

Best regards,
--  
Nathan Chancellor <nathan@kernel.org>


             reply	other threads:[~2025-07-15 22:56 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-15 22:56 Nathan Chancellor [this message]
2025-07-16 10:08 ` [PATCH] memstick: core: Zero initialize id_reg in h_memstick_read_dev_id() Ulf Hansson

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