From: trix@redhat.com
To: jack@suse.cz, william.kucharski@oracle.com, jeffm@suse.com,
willy@infradead.org, joseph.qi@linux.alibaba.com,
liao.pingfang@zte.com.cn
Cc: reiserfs-devel@vger.kernel.org, linux-kernel@vger.kernel.org,
Tom Rix <trix@redhat.com>
Subject: [PATCH] reiserfs : fix improper free in reiserfs_get_block
Date: Tue, 14 Jul 2020 06:05:09 -0700 [thread overview]
Message-ID: <20200714130509.11791-1-trix@redhat.com> (raw)
From: Tom Rix <trix@redhat.com>
clang static analysis flags this error
inode.c:1083:5: warning: Argument to kfree() is the address of the
local variable 'unf_single', which is not memory allocated by
malloc() [unix.Malloc]
kfree(un);
^~~~~~~~~
Assignment of 'un'
/*
* We use this in case we need to allocate
* only one block which is a fastpath
*/
unp_t unf_single = 0;
...
if (blocks_needed == 1) {
un = &unf_single;
} else {
un = kcalloc(min(blocks_needed, max_to_insert),
UNFM_P_SIZE, GFP_NOFS);
if (!un) {
un = &unf_single;
blocks_needed = 1;
max_to_insert = 0;
}
}
The logic to free 'un'
if (blocks_needed != 1)
kfree(un);
Because the kcalloc failure falls back to using unf_single,
the if-check for the free is wrong.
So improve the check.
Signed-off-by: Tom Rix <trix@redhat.com>
---
fs/reiserfs/inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 1509775da040..4d62148e43e6 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -1079,7 +1079,7 @@ int reiserfs_get_block(struct inode *inode, sector_t block,
UNFM_P_SIZE *
blocks_needed);
- if (blocks_needed != 1)
+ if (un != &unf_single)
kfree(un);
if (retval) {
--
2.18.1
next reply other threads:[~2020-07-14 13:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 13:05 trix [this message]
2020-07-14 13:10 ` [PATCH] reiserfs : fix improper free in reiserfs_get_block Matthew Wilcox
2020-07-14 13:12 ` Tom Rix
2020-07-15 8:04 ` Jan Kara
2020-07-16 13:48 ` Tom Rix
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