From: "Shradha Todi" <shradha.t@samsung.com>
To: "'Leon Romanovsky'" <leon@kernel.org>
Cc: <linux-kernel@vger.kernel.org>, <linux-pci@vger.kernel.org>,
<bhelgaas@google.com>, <kishon@ti.com>,
<lorenzo.pieralisi@arm.com>, <pankaj.dubey@samsung.com>,
<sriram.dash@samsung.com>, <niyas.ahmed@samsung.com>,
<p.rajanbabu@samsung.com>, <l.mehra@samsung.com>,
<hari.tv@samsung.com>
Subject: RE: [PATCH v4] PCI: endpoint: Fix NULL pointer dereference for ->get_features()
Date: Tue, 19 Jan 2021 15:25:10 +0530 [thread overview]
Message-ID: <147801d6ee49$2ecd2d30$8c678790$@samsung.com> (raw)
In-Reply-To: <20210113072104.GH4678@unreal>
> -----Original Message-----
> From: Leon Romanovsky <leon@kernel.org>
> Subject: Re: [PATCH v4] PCI: endpoint: Fix NULL pointer dereference for -
> >get_features()
>
> On Tue, Jan 12, 2021 at 07:32:25PM +0530, Shradha Todi wrote:
> > get_features ops of pci_epc_ops may return NULL, causing NULL pointer
> > dereference in pci_epf_test_bind function. Let us add a check for
> > pci_epc_feature pointer in pci_epf_test_bind before we access it to
> > avoid any such NULL pointer dereference and return -ENOTSUPP in case
> > pci_epc_feature is not found.
> >
> > When the patch is not applied and EPC features is not implemented in
> > the platform driver, we see the following dump due to kernel NULL
> > pointer dereference.
> >
> > [ 105.135936] Call trace:
> > [ 105.138363] pci_epf_test_bind+0xf4/0x388 [ 105.142354]
> > pci_epf_bind+0x3c/0x80 [ 105.145817] pci_epc_epf_link+0xa8/0xcc [
> > 105.149632] configfs_symlink+0x1a4/0x48c [ 105.153616]
> > vfs_symlink+0x104/0x184 [ 105.157169] do_symlinkat+0x80/0xd4 [
> > 105.160636] __arm64_sys_symlinkat+0x1c/0x24 [ 105.164885]
> > el0_svc_common.constprop.3+0xb8/0x170
> > [ 105.169649] el0_svc_handler+0x70/0x88 [ 105.173377]
> > el0_svc+0x8/0x640 [ 105.176411] Code: d2800581 b9403ab9 f9404ebb
> > 8b394f60 (f9400400) [ 105.182478] ---[ end trace a438e3c5a24f9df0
> > ]---
>
>
> Description and call trace don't correlate with the proposed code change.
>
> The code in pci_epf_test_bind() doesn't dereference epc_features, at least
in
> direct manner.
>
> Thanks
Thanks for the review. Yes, you're right. The dereference does not happen in
the pci_epf_test_bind() itself, but in pci_epf_test_alloc_space() being
called within. We will update the line "causing NULL pointer dereference in
pci_epf_test_bind function. " in the commit message to "causing NULL pointer
dereference in pci_epf_test_alloc_space function. " Would that be good
enough?
next prev parent reply other threads:[~2021-01-19 13:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210112140234epcas5p4f97e9cf12e68df9fb55d1270bd14280c@epcas5p4.samsung.com>
2021-01-12 14:02 ` [PATCH v4] PCI: endpoint: Fix NULL pointer dereference for ->get_features() Shradha Todi
2021-01-13 5:05 ` Kishon Vijay Abraham I
2021-01-13 7:21 ` Leon Romanovsky
2021-01-19 9:55 ` Shradha Todi [this message]
2021-01-20 5:29 ` Leon Romanovsky
2021-01-27 9:11 ` Shradha Todi
2021-03-23 11:05 ` Lorenzo Pieralisi
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