kernel panic while building SDIO driver

[Stanislav Sedov]

> On Apr 15, 2018, at 8:01 AM, Udit agarwal <dev.madaari at gmail.com> wrote:
> 
> Hi,
> I have been trying to build the kernel (for BBB) invoking SDIO driver from
> FreeBSD latest src tree using BEAGLEBONE-MMCCAM kernconf file(Yes, I added
> that file manually). I seems like the kernel panics due to sleep
> lock(complete logs:
> https://gist.github.com/madaari/4779d75e7f1ab88369318a40cb026d9b )
> 
> mmc_dev_async(async_code=0x20, path_id=1, target_id=0, lun_id=0
> Got AC_PATH_REGISTERED -- whatever...
> mmc_dev_async(async_code=0x20, path_id=1, target_id=ffffffff,
> lun_id=ffffffff
> usbus0: 480Mbps High Speed USB v2.0
> usbus1: 480Mbps High Speed USB v2.0
> (noperiph:sdhci_slot0:0:-1:ffffffff): XPT_SCAN_{BUS,TGT,LUN}
> Kernel page fault with the following non-sleepable locks held:
> exclusive sleep mutex CAM device lock (CAM device lock) r = 0 (0xc30e1464)
> lock2
> stack backtrace:
> Fatal kernel mode data abort: 'Translation Fault (L1)' on read
> trapframe: 0xd0dc0ac0
> FSR=00000005, FAR=00000010, spsr=60000013
> r0 =00000061, r1 =00000188, r2 =d0dc0a8c, r3 =60000013
> r4 =c30e0000, r5 =c30dec40, r6 =00000000, r7 =d0dc0b68
> r8 =c086f528, r9 =c068f050, r10=00000000, r11=d0dc0d10
> r12=00000062, ssp=d0dc0b50, slr=c002b77c, pc =c002b5c0
> [ thread pid 4 tid 100048 ]
> Stopped at mmc_action+0x94: ldr r6, [r6, #0x010]
> db>
> 
> Any idea how to resolve this?
> 

It actually panicked on read fault (see L1 translation failure) on trying to read the address which isn’t mapped.  From the obstruction printed, it appears to be r6, which is 0x0 — most likely a NULL pointer dereference in the code.  What is at mmc_action+0x95 in your kernel?

--
Stas