linux-kernel - [GIT PULL 2/2] lightnvm: fix uninitialized pointer in nvm_remove

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Message-Id: <20190621091200.23168-3-mb@lightnvm.io>
Date:   Fri, 21 Jun 2019 11:12:00 +0200
From:   Matias Bjørling <mb@...htnvm.io>
To:     axboe@...com
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Matias Bjørling <mb@...htnvm.io>
Subject: [GIT PULL 2/2] lightnvm: fix uninitialized pointer in nvm_remove_tgt()

From: Geert Uytterhoeven <geert@...ux-m68k.org>

With gcc 4.1:

    drivers/lightnvm/core.c: In function ‘nvm_remove_tgt’:
    drivers/lightnvm/core.c:510: warning: ‘t’ is used uninitialized in this function

Indeed, if no NVM devices have been registered, t will be an
uninitialized pointer, and may be dereferenced later.  A call to
nvm_remove_tgt() can be triggered from userspace by issuing the
NVM_DEV_REMOVE ioctl on the lightnvm control device.

Fix this by preinitializing t to NULL.

Fixes: 843f2edbdde085b4 ("lightnvm: do not remove instance under global lock")
Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Signed-off-by: Matias Bjørling <mb@...htnvm.io>
---
 drivers/lightnvm/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 7d555b110ecd..a600934fdd9c 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -478,7 +478,7 @@ static void __nvm_remove_target(struct nvm_target *t, bool graceful)
  */
 static int nvm_remove_tgt(struct nvm_ioctl_remove *remove)
 {
-	struct nvm_target *t;
+	struct nvm_target *t = NULL;
 	struct nvm_dev *dev;
 
 	down_read(&nvm_lock);
-- 
2.19.1