linux-kernel - [PATCH] fs: pstore: fix double-free on ramoops_init

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Message-Id: <20200107110445.162404-1-cengiz@kernel.wtf>
Date:   Tue,  7 Jan 2020 14:04:46 +0300
From:   Cengiz Can <cengiz@...nel.wtf>
To:     linux-kernel@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Tony Luck <tony.luck@...el.com>
Cc:     Cengiz Can <cengiz@...nel.wtf>
Subject: [PATCH] fs: pstore: fix double-free on ramoops_init_przs

According to Coverity scanner (CID 1457526) kfree on ram.c:591 frees
label which has already been freed.

Here's the flow as I have understood (this is my first time reading
pstore's files):

Whenever `persistent_ram_new` fails, it implicitly calls
`persistent_ram_free(prz)` which already does `kfree(prz->label)` and a
`kfree(prz)` consequently.

Removed `kfree(label)` to prevent double-free.

Signed-off-by: Cengiz Can <cengiz@...nel.wtf>
---
 fs/pstore/ram.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 487ee39b4..e196aa08f 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -588,7 +588,6 @@ static int ramoops_init_przs(const char *name,
 			dev_err(dev, "failed to request %s mem region (0x%zx@...llx): %d\n",
 				name, record_size,
 				(unsigned long long)*paddr, err);
-			kfree(label);
 
 			while (i > 0) {
 				i--;
-- 
2.24.1