From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: [REGRESSION] brcmfmac: NULL pointer deference starting next-20181107 Date: Tue, 13 Nov 2018 14:32:54 +0100 Message-ID: References: <9f72ac4f-a83a-7af7-3c26-b1ced6d98653@broadcom.com> <9e0a7997-4c14-a3a1-c935-d674270533aa@redhat.com> <000bfd39-10cf-661c-9512-0410782168dc@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <000bfd39-10cf-661c-9512-0410782168dc@nvidia.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jon Hunter , Arend van Spriel , Kalle Valo , linux-tegra , linux-wireless@vger.kernel.org, Linux Kernel Mailing List , Ard Biesheuvel List-Id: linux-tegra@vger.kernel.org HI, On 13-11-18 14:21, Jon Hunter wrote: > > On 13/11/2018 10:40, Hans de Goede wrote: >> Hi, >> >> On 13-11-18 11:24, Arend van Spriel wrote: >>> + Ard as this involves EFI. >>> >>> On 11/12/2018 2:24 PM, Jon Hunter wrote: >>>> Hi Hans, Kalle, >>>> >>>> Starting with next-20181107 I am seeing the following NULL pointer >>>> deference on Tegra (note the firmware is missing on this board) ... >>>> >>>> [   14.072883] brcmfmac: brcmf_fw_alloc_request: using >>>> brcm/brcmfmac4329-sdio for chip BCM4329/3 >>>> >>>> [   14.130287] brcmfmac mmc1:0001:1: Direct firmware load for >>>> brcm/brcmfmac4329-sdio.nvidia,cardhu-a04.txt failed with error -2 >>>> >>>> [   14.156283] brcmfmac mmc1:0001:1: Direct firmware load for >>>> brcm/brcmfmac4329-sdio.txt failed with error -2 >>>> >>>> [   14.177769] Unable to handle kernel NULL pointer dereference at >>>> virtual address 00000008 >>>> >>>> [   14.197303] pgd = 60bfa5f1 >>>> >>>> [   14.211842] [00000008] *pgd=00000000 >>>> >>>> [   14.227373] Internal error: Oops: 5 [#1] SMP ARM >>>> >>>> [   14.244244] Modules linked in: brcmfmac sha256_generic sha256_arm >>>> snd cfg80211 brcmutil soundcore snd_soc_tegra30_ahub tegra_wdt >>>> >>>> [   14.269109] CPU: 1 PID: 114 Comm: kworker/1:2 Not tainted >>>> 4.20.0-rc1-next-20181107-gd881de3 #1 >>>> >>>> [   14.269114] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree) >>>> >>>> [   14.269154] Workqueue: events request_firmware_work_func >>>> >>>> [   14.269177] PC is at efivar_entry_size+0x28/0x90 >>>> >>>> [   14.269362] LR is at brcmf_fw_complete_request+0x3f8/0x8d4 [brcmfmac] >>>> >>>> [   14.269369] pc : []    lr : []    psr: a00d0113 >>>> >>>> [   14.269374] sp : ede7fe28  ip : ee983410  fp : c1787f30 >>>> >>>> [   14.269378] r10: 00000000  r9 : 00000000  r8 : bf2b2258 >>>> >>>> [   14.269384] r7 : ee983000  r6 : c1604c48  r5 : ede7fe88  r4 : >>>> edf337c0 >>>> >>>> [   14.269389] r3 : 00000000  r2 : 00000000  r1 : ede7fe88  r0 : >>>> c17712c8 >>>> >>> >>> Hi Jon, >>> >>> I tried building drivers/firmware/efi/vars.c using tegra_defconfig. >>> Had to enable CONFIG_EFI. So the null pointer access is a 0x00000008 >>> so I looked at the disassembly below: >>> >>> int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) >>> { >>>       310:       e1a05001        mov     r5, r1 >>>          const struct efivar_operations *ops = __efivars->ops; >>> ==>  314:       e5936008        ldr     r6, [r3, #8] >>> >>> So I think __efivars is NULL on your platform. It is private to the >>> source file. Not sure how the driver should deal with this. Maybe use >>> efi_enabled() but not sure what feature to use. My best bet would be >>> EFI_RUNTIME_SERVICES. >> >> Ah right, thank you for catching this I had looking into this >> on my TODO list, but you beat me to it. >> >> IMHO the best fix here would be to modify efivar_entry_size(), >> adding: >> >>     if (!ops) >>         return -ENOENT; >> >> Which makes it return the same error as when we do have efivar >> support but the requested variable is not found. > > So the above did not work. I see a patch from Arend and I will give this > a try. Ah right, looking at Arend's patch my little snippet got the test wrong. Hopefully Arend's patch will fix things. Regards, Hans