Re: [REGRESSION] brcmfmac: NULL pointer deference starting next-20181107

From: Hans de Goede
Date: Tue Nov 13 2018 - 05:40:16 EST

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) ...

[ÂÂ 14.072883] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4329-sdio for chip BCM4329/3

[ÂÂ 14.130287] brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac4329-sdio.nvidia,cardhu-a04.txt failed with error -2

[ÂÂ 14.156283] brcmfmac mmc1:0001:1: Direct firmware load for brcm/brcmfmac4329-sdio.txt failed with error -2

[ÂÂ 14.177769] Unable to handle kernel NULL pointer dereference at virtual address 00000008

[ÂÂ 14.197303] pgd = 60bfa5f1

[ÂÂ 14.211842] [00000008] *pgd=00000000

[ÂÂ 14.227373] Internal error: Oops: 5 [#1] SMP ARM

[ÂÂ 14.244244] Modules linked in: brcmfmac sha256_generic sha256_arm snd cfg80211 brcmutil soundcore snd_soc_tegra30_ahub tegra_wdt

[ÂÂ 14.269109] CPU: 1 PID: 114 Comm: kworker/1:2 Not tainted 4.20.0-rc1-next-20181107-gd881de3 #1

[ÂÂ 14.269114] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)

[ÂÂ 14.269154] Workqueue: events request_firmware_work_func

[ÂÂ 14.269177] PC is at efivar_entry_size+0x28/0x90

[ÂÂ 14.269362] LR is at brcmf_fw_complete_request+0x3f8/0x8d4 [brcmfmac]

[ÂÂ 14.269369] pc : [<c0c40718>]ÂÂÂ lr : [<bf2a3ef4>]ÂÂÂ psr: a00d0113

[ÂÂ 14.269374] sp : ede7fe28Â ip : ee983410Â fp : c1787f30

[ÂÂ 14.269378] r10: 00000000Â r9 : 00000000Â r8 : bf2b2258

[ÂÂ 14.269384] r7 : ee983000Â r6 : c1604c48Â r5 : ede7fe88Â r4 : edf337c0

[ÂÂ 14.269389] r3 : 00000000Â r2 : 00000000Â r1 : ede7fe88Â 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)
{
ÂÂÂÂ 310:ÂÂÂÂÂÂ e1a05001ÂÂÂÂÂÂÂ movÂÂÂÂ r5, r1
ÂÂÂÂÂÂÂ const struct efivar_operations *ops = __efivars->ops;
==>Â 314:ÂÂÂÂÂÂ e5936008ÂÂÂÂÂÂÂ ldrÂÂÂÂ 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.

Regards,

Hans






ÂÂÂÂÂÂÂ efi_status_t status;

ÂÂÂÂÂÂÂ *size = 0;
ÂÂÂÂ 318:ÂÂÂÂÂÂ e3a03000ÂÂÂÂÂÂÂ movÂÂÂÂ r3, #0
ÂÂÂÂ 31c:ÂÂÂÂÂÂ e5813000ÂÂÂÂÂÂÂ strÂÂÂÂ r3, [r1]

ÂÂÂÂÂÂÂ if (down_interruptible(&efivars_lock))
ÂÂÂÂ 320:ÂÂÂÂÂÂ ebfffffeÂÂÂÂÂÂÂ blÂÂÂÂÂ 0 <down_interruptible>
ÂÂÂÂ 324:ÂÂÂÂÂÂ e2504000ÂÂÂÂÂÂÂ subsÂÂÂ r4, r0, #0
ÂÂÂÂ 328:ÂÂÂÂÂÂ 1a000012ÂÂÂÂÂÂÂ bneÂÂÂÂ 378 <efivar_entry_size+0x80>
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ return -EINTR;
ÂÂÂÂÂÂÂ status = ops->get_variable(entry->var.VariableName,

Regards,
Arend

[ 14.269398] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none

[ 14.269404] Control: 10c5387d Table: ad16804a DAC: 00000051

[ÂÂ 14.269417] Process kworker/1:2 (pid: 114, stack limit = 0x984bfbff)

[ÂÂ 14.269423] Stack: (0xede7fe28 to 0xede80000)

[ÂÂ 14.269434] fe20:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 00000000 c1604c48 edf336e0 edf337c0 ee983000 c1604c48

[ÂÂ 14.269447] fe40: edf336e0 bf2a3ef4 edf339db c0466bcc edf339c0 edd1417c edd14008 00000000

[ÂÂ 14.269460] fe60: 006000c0 edf33b40 edf339c0 edf33250 c0f9110c edf33b40 c17db2d0 edf339c0

[ÂÂ 14.269471] fe80: 00000000 edd14008 00000000 0076006e 00610072 0000006d edf33940 00000003

[ÂÂ 14.269482] fea0: edf33980 c0923f84 edf33840 edf33940 edf33980 ede7ff1c c0f9110c c0924410

[ÂÂ 14.269492] fec0: 7fffffff d9025ae9 00000001 edf337c0 00000000 ef7b9e00 edf33804 ef7bd000

[ÂÂ 14.269512] fee0: 00000000 00000000 c1787f30 bf2a4438 ee952280 00000000 edf33800 ee952280

[ÂÂ 14.678917] ff00: ef7b9e00 edf33804 ef7bd000 c0924738 00000000 00000003 00000001 edf33940

[ÂÂ 14.678931] ff20: edf33800 c035ee0c ef7b9e00 ef7b9e18 ede7e018 ee952280 ef7b9e00 ef7b9e18

[ÂÂ 14.720757] ff40: ede7e018 c17878b8 ee952294 c1603d00 00000008 c035f130 eea99d9c ede7e000

[ÂÂ 14.720769] ff60: ee970740 c1603d00 eea99d9c eea99d80 ee970740 00000000 eea99d9c ee952280

[ÂÂ 14.720785] ff80: c035f0f0 ee911ebc 00000000 c0364418 ee970740 c03642f0 00000000 00000000

[ÂÂ 14.783682] ffa0: 00000000 00000000 00000000 c03010e8 00000000 00000000 00000000 00000000

[ÂÂ 14.783693] ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

[ÂÂ 14.783707] ffe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000

[ÂÂ 14.846132] [<c0c40718>] (efivar_entry_size) from [<bf2a3ef4>] (brcmf_fw_complete_request+0x3f8/0x8d4 [brcmfmac])

[ÂÂ 14.846253] [<bf2a3ef4>] (brcmf_fw_complete_request [brcmfmac]) from [<bf2a4438>] (brcmf_fw_request_done+0x68/0x11c [brcmfmac])

[ÂÂ 14.893363] [<bf2a4438>] (brcmf_fw_request_done [brcmfmac]) from [<c0924738>] (request_firmware_work_func+0x40/0x68)

[ÂÂ 14.893396] [<c0924738>] (request_firmware_work_func) from [<c035ee0c>] (process_one_work+0x164/0x448)

[ÂÂ 14.939206] [<c035ee0c>] (process_one_work) from [<c035f130>] (worker_thread+0x40/0x524)

[ÂÂ 14.939228] [<c035f130>] (worker_thread) from [<c0364418>] (kthread+0x128/0x158)

[ÂÂ 14.981096] [<c0364418>] (kthread) from [<c03010e8>] (ret_from_fork+0x14/0x2c)

[ÂÂ 14.981102] Exception stack(0xede7ffb0 to 0xede7fff8)

[ÂÂ 14.981112] ffa0:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 00000000 00000000 00000000 00000000

[ÂÂ 15.041390] ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

[ÂÂ 15.041399] ffe0: 00000000 00000000 00000000 00000000 00000013 00000000

[ÂÂ 15.041415] Code: e1a07000 e30102c8 e34c0177 e1a05001 (e5926008)

[ÂÂ 15.041491] ---[ end trace 06697c36d390de92 ]---