clang static analysis flags this error
qat_uclo.c:297:3: warning: Attempt to free released memory
[unix.Malloc]
kfree(*init_tab_base);
^~~~~~~~~~~~~~~~~~~~~
When input *init_tab_base is null, the function allocates memory for
the head of the list. When there is problem allocating other list
elements the list is unwound and freed. Then a check is made if the
list head was allocated and is also freed.
Keeping track of the what may need to be freed is the variable 'tail_old'.
The unwinding/freeing block is
while (tail_old) {
mem_init = tail_old->next;
kfree(tail_old);
tail_old = mem_init;
}
The problem is that the first element of tail_old is also what was
allocated for the list head
init_header = kzalloc(sizeof(*init_header), GFP_KERNEL);
...
*init_tab_base = init_header;
flag = 1;
}
tail_old = init_header;
So *init_tab_base/init_header are freed twice.
There is another problem.
When the input *init_tab_base is non null the tail_old is calculated by
traveling down the list to first non null entry.
tail_old = init_header;
while (tail_old->next)
tail_old = tail_old->next;
When the unwinding free happens, the last entry of the input list will
be freed.
So the freeing needs a general changed.
If locally allocated the first element of tail_old is freed, else it
is skipped. As a bit of cleanup, reset *init_tab_base if it came in
as null.
Fixes: b4b7e67c91 ("crypto: qat - Intel(R) QAT ucode part of fw loader")
Cc: <stable@vger.kernel.org>
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
c06c76602e