From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin Ian King Date: Tue, 23 Jun 2020 11:12:42 +0000 Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check Message-Id: List-Id: References: <20200622153546.49880-1-colin.king@canonical.com> <20200622182816.GF4151@kadam> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Song Bao Hua (Barry Song)" , Dan Carpenter Cc: Seth Jennings , Dan Streetman , Vitaly Wool , Andrew Morton , Stephen Rothwell , "linux-mm@kvack.org" , "kernel-janitors@vger.kernel.org" , "linux-kernel@vger.kernel.org" On 22/06/2020 20:55, Song Bao Hua (Barry Song) wrote: > > >> -----Original Message----- >> From: Dan Carpenter [mailto:dan.carpenter@oracle.com] >> Sent: Tuesday, June 23, 2020 6:28 AM >> To: Colin King >> Cc: Seth Jennings ; Dan Streetman >> ; Vitaly Wool ; Andrew >> Morton ; Song Bao Hua (Barry Song) >> ; Stephen Rothwell ; >> linux-mm@kvack.org; kernel-janitors@vger.kernel.org; >> linux-kernel@vger.kernel.org >> Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and >> rework kzalloc failure check >> >> On Mon, Jun 22, 2020 at 04:35:46PM +0100, Colin King wrote: >>> From: Colin Ian King >>> >>> kzalloc failures return NULL on out of memory errors, so replace the >>> IS_ERR_OR_NULL check with the usual null pointer check. Fix two memory >>> leaks with on acomp and acomp_ctx by ensuring these objects are free'd >>> on the error return path. >>> >>> Addresses-Coverity: ("Resource leak") >>> Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for >> hardware acceleration") >>> Signed-off-by: Colin Ian King > > > Colin, thanks for your patch. I am sorry I did the same thing with you here: > https://lkml.org/lkml/2020/6/22/347 Thanks for fixing this correctly, I ran out of time yesterday to re-do the fix. Colin > > >>> --- >>> mm/zswap.c | 16 +++++++++++----- >>> 1 file changed, 11 insertions(+), 5 deletions(-) >>> >>> diff --git a/mm/zswap.c b/mm/zswap.c >>> index 0d914ba6b4a0..14839cbac7ff 100644 >>> --- a/mm/zswap.c >>> +++ b/mm/zswap.c >>> @@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int >> cpu, struct hlist_node *node) >>> return 0; >>> >>> acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL); >>> - if (IS_ERR_OR_NULL(acomp_ctx)) { >>> + if (!acomp_ctx) { >>> pr_err("Could not initialize acomp_ctx\n"); >>> return -ENOMEM; >>> } >>> acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0); >>> - if (IS_ERR_OR_NULL(acomp)) { >>> + if (!acomp) { >> >> This should be IS_ERR(acomp). Please preserve the error code. >> >>> pr_err("could not alloc crypto acomp %s : %ld\n", >>> pool->tfm_name, PTR_ERR(acomp)); >>> - return -ENOMEM; >>> + goto free_acomp_ctx; >>> } >>> acomp_ctx->acomp = acomp; >>> >>> req = acomp_request_alloc(acomp_ctx->acomp); >>> - if (IS_ERR_OR_NULL(req)) { >>> + if (!req) { >>> pr_err("could not alloc crypto acomp %s : %ld\n", >>> pool->tfm_name, PTR_ERR(acomp)); >>> - return -ENOMEM; >>> + goto free_acomp; >>> } >>> acomp_ctx->req = req; >>> >>> @@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int >> cpu, struct hlist_node *node) >>> *per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx; >>> >>> return 0; >>> + >>> +free_acomp: >>> + kfree(acomp); >> >> The kfree() isn't correct. It needs to be: >> >> crypto_free_acomp(acomp); >> >>> +free_acomp_ctx: >>> + kfree(acomp_ctx); >>> + return -ENOMEM; >> >> regards, >> dan carpenter >