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 : [<c0c40718>] lr : [<bf2a3ef4>] 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. Cheers Jon -- nvpublic