From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2120.oracle.com ([141.146.126.78]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ivEX1-0001qL-B1 for linux-um@lists.infradead.org; Sat, 25 Jan 2020 06:02:56 +0000 Date: Sat, 25 Jan 2020 09:01:52 +0300 From: Dan Carpenter Subject: Re: [PATCH] um: Fix some error handling in uml_vector_user_bpf() Message-ID: <20200125060152.GN1847@kadam> References: <20200124101450.jxfzsh6sz7v324hv@kili.mountain> <36070c96-8e75-7d06-d945-87a9d366d0b9@cambridgegreys.com> <20200124164427.GF1870@kadam> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Anton Ivanov Cc: kernel-janitors@vger.kernel.org, Daniel Borkmann , Richard Weinberger , Jeff Dike , linux-um@lists.infradead.org, Song Liu , Alexei Starovoitov , Alex Dewar , Yonghong Song , bpf@vger.kernel.org, Andrii Nakryiko , Martin KaFai Lau On Fri, Jan 24, 2020 at 04:48:03PM +0000, Anton Ivanov wrote: > > > On 24/01/2020 16:44, Dan Carpenter wrote: > > On Fri, Jan 24, 2020 at 12:52:18PM +0000, Anton Ivanov wrote: > > > > > > > > > On 24/01/2020 10:14, Dan Carpenter wrote: > > > > 1) The uml_vector_user_bpf() returns pointers so it should return NULL > > > > instead of false. > > > > 2) If the "bpf_prog" allocation failed, it would have eventually lead to > > > > a crash. We can't succeed after the error happens so it should just > > > > return. > > > > > > > > Fixes: 9807019a62dc ("um: Loadable BPF "Firmware" for vector drivers") > > > > Signed-off-by: Dan Carpenter > > > > --- > > > > arch/um/drivers/vector_user.c | 10 +++++----- > > > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c > > > > index ddcd917be0af..88483f5b034c 100644 > > > > --- a/arch/um/drivers/vector_user.c > > > > +++ b/arch/um/drivers/vector_user.c > > > > @@ -732,13 +732,13 @@ void *uml_vector_user_bpf(char *filename) > > > > if (stat(filename, &statbuf) < 0) { > > > > printk(KERN_ERR "Error %d reading bpf file", -errno); > > > > - return false; > > > > + return NULL; > > > > > > I will sort this one out, thanks for noticing. > > > > > > > } > > > > bpf_prog = uml_kmalloc(sizeof(struct sock_fprog), UM_GFP_KERNEL); > > > > - if (bpf_prog != NULL) { > > > > - bpf_prog->len = statbuf.st_size / sizeof(struct sock_filter); > > > > - bpf_prog->filter = NULL; > > > > - } > > > > + if (!pfg_prog) > > > > > > ^^^^^ ? > > > > If we don't return here it leads to a NULL dereference. > > It says pfg_prog > > I cannot find this identifier :) > Oh wow... That's very embarrassing. My QC scripts do compile these as part of the process. But this wasn't a in of my allmodconfig and when I do "make arch/um/drivers/vector_user.o", it just silently returns without printing anything. I didn't notice that it hadn't built. Even "make V=2 arch/um/drivers/vector_user.o" doesn't generate output. I will resend the patch (on Monday though). regards, dan carpenter _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um