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Tue, 19 Jan 2021 19:39:46 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p2.samsung.com (KnoxPortal) with ESMTPA id 20210119095514epcas5p2f4b4f456955a8be3d05f094d38168b13~bmYsOQlMv1399313993epcas5p2L; Tue, 19 Jan 2021 09:55:14 +0000 (GMT) Received: from epsmgms1p2.samsung.com (unknown [182.195.42.42]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20210119095514epsmtrp2d472b2636a457d608dbe4c93ea4b8341~bmYsNYkfH1714417144epsmtrp2U; Tue, 19 Jan 2021 09:55:14 +0000 (GMT) X-AuditID: b6c32a4a-6c9ff7000000c5dc-f0-6006b6f2c65e Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p2.samsung.com (Symantec Messaging Gateway) with SMTP id F3.F6.08745.28CA6006; Tue, 19 Jan 2021 18:55:14 +0900 (KST) Received: from shradhat02 (unknown [107.122.8.248]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20210119095512epsmtip1746f9e82069f4017eeeb552946cd0fc7~bmYqbTBGT1120911209epsmtip1k; Tue, 19 Jan 2021 09:55:12 +0000 (GMT) From: "Shradha Todi" To: "'Leon Romanovsky'" Cc: , , , , , , , , , , In-Reply-To: <20210113072104.GH4678@unreal> Subject: RE: [PATCH v4] PCI: endpoint: Fix NULL pointer dereference for ->get_features() Date: Tue, 19 Jan 2021 15:25:10 +0530 Message-ID: <147801d6ee49$2ecd2d30$8c678790$@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQGwxsy/0exZ02HWY9tkJuphsuoUGQKa3YDmAkSCdsmqVAjF8A== Content-Language: en-us X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrJKsWRmVeSWpSXmKPExsWy7bCmpu6nbWwJBv8msVksacqw+DhtJZPF hac9bBZ3nt9gtJjyaymzxeVdc9gszs47zmbx5vcLdosnUx6xWhzdGGyxaOsXdosb69kdeDzW zFvD6LFgU6nHplWdbB59W1Yxehy/sZ3J4/MmuQC2KC6blNSczLLUIn27BK6MCecuMBWs46/Y veoAcwPjeZ4uRg4OCQETiRMvMrsYuTiEBHYzSnzp28cO4XxilJjZ+okVwvnMKHGhYwVTFyMn WMfnu0uZIBK7GCWmtc5mhHBeMErM2tjHDlLFJqAj8eTKH2YQW0RAU2JD7yU2kCJmgeVMEnOu tIGN4hTQluh+upMFxBYWiJI4P2c+WAOLgKrEuZf3wOK8ApYSZ6d/ZoKwBSVOznwCFmcWkJfY /nYOM8RJChI/ny5jhVjmJHFhwm5GiBpxiZdHj7BD1BzgkDi3KQ/CdpGYvvEEVFxY4tXxLVC2 lMTnd3vZIOx8iakXnrJAAqlCYnlPHUTYXuLAlTlgYWagv9bv0ocIy0pMPbWOCWIrn0Tv7yfQ wOKV2DEPxlaW+PJ3DwuELSkx79hl1gmMSrOQPDYLyWOzkDwwC2HbAkaWVYySqQXFuempxaYF Rnmp5XrFibnFpXnpesn5uZsYwalLy2sH48MHH/QOMTJxMB5ilOBgVhLhLV3HlCDEm5JYWZVa lB9fVJqTWnyIUZqDRUmcd4fBg3ghgfTEktTs1NSC1CKYLBMHp1QD0/ZE51y++ANCoacfXeUz itZ6+I9n9a2Lgn5ND/OM2Hyfxu1ZvOr13S8qshlvj3X9/H7d8ptvaaXMeb9oT6u07ltmovyv bBd2u5WLrZK+YtyRq/OVz/lSZ9gSPlGlzSm/WGy2RIr+85JwvHpeai2D0Sf1r3VtB4IPZ8z8 u5j17ALhE/6d9QfSJCRilvKKvCmvOzFH9sC0thSBTkXZm7fZtvc5cgjKRbXuY+Ur94/7tUMm c/2cp23rfvwKy3iwlOkKU8MLJ+4GPdXct325P3ec+2+wJEDv9L4si9MHtOKvnV+6KPz0tyZT 858Lfx7bLj1jA3/q1yMz7Z6+dlCr3FlmbfV7geyfQ1Lhmoy3p05+rsRSnJFoqMVcVJwIANzI fGPMAwAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprDIsWRmVeSWpSXmKPExsWy7bCSnG7TGrYEg5c9LBZLmjIsPk5byWRx 4WkPm8Wd5zcYLab8WspscXnXHDaLs/OOs1m8+f2C3eLJlEesFkc3Blss2vqF3eLGenYHHo81 89YweizYVOqxaVUnm0ffllWMHsdvbGfy+LxJLoAtissmJTUnsyy1SN8ugStjwrkLTAXr+Ct2 rzrA3MB4nqeLkZNDQsBE4vPdpUxdjFwcQgI7GCX+LN/DDJGQlPh8cR0ThC0ssfLfc3YQW0jg GaPEy//+IDabgI7Ekyt/wOpFBDQlNvReYgMZxCywmUlixdl/LBBTtzFKHPzVCTaJU0Bbovvp ThYQW1ggQmLljgNg3SwCqhLnXt4Di/MKWEqcnf6ZCcIWlDg58wlQnANoqp5E20ZGkDCzgLzE 9rdzoA5VkPj5dBkrxBFOEhcm7IaqEZd4efQI+wRG4VlIJs1CmDQLyaRZSDoWMLKsYpRMLSjO Tc8tNiwwykst1ytOzC0uzUvXS87P3cQIjkAtrR2Me1Z90DvEyMTBeIhRgoNZSYS3dB1TghBv SmJlVWpRfnxRaU5q8SFGaQ4WJXHeC10n44UE0hNLUrNTUwtSi2CyTBycUg1MK61PqBmdz7n7 dLbi3KWSN48IKBXJcj1LqrLdpjopNU90qmDIoS+silXnjfp/sJ3IY1Ds5w3Kz2SafoFv85PX Nt9aRY5ws5yVYF9vvELcS6diveO+c+mtU+cLTn9+x1og1CDj5gw7l5n1UgvfRlZXunSmxRZP lg7m2Xb4auYtlbxzEXc81NKvFeVx5FVEyWbWh95e+ivDc92iF2tPM0/Q/Xai+sG0wPQqRol/ EzfGPN+yryvv8t6Xtc9/aV/v7mmu27y9vvXUj9XJXpyeJ/X8TT/vPZtsHb/9pm3c3rT2/RXu XuzyRyxyAvS7D36ccEr2isO3uzecJuxM7p7+JJ77SHroHaYFnFLbYkubPDiUWIozEg21mIuK EwGcfR+sLwMAAA== X-CMS-MailID: 20210119095514epcas5p2f4b4f456955a8be3d05f094d38168b13 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P X-CMS-RootMailID: 20210112140234epcas5p4f97e9cf12e68df9fb55d1270bd14280c References: <1610460145-14645-1-git-send-email-shradha.t@samsung.com> <20210113072104.GH4678@unreal> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Leon Romanovsky > 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?