Crash with a alignment trap issue when trying to view video files on a raspberry pi 2b

[BadlyDrawnBoy]

Crash with a alignment trap issue when trying to view video files on a raspberry pi 2b

[phillipberndt]

Does echo 3 > /proc/cpu/alignment help? (That is, asking the kernel to fix these up for you.)

If you want to fix the alignment issues that'll be some work, I didn't pay any attention to that when writing pqiv.

[BadlyDrawnBoy]

Hi,
thanks a lot for the quick reply! No, sadly it does not. I read somewhere that it may help to switch off the compiler optimization, but it has no effect. Also my initial thought that it is crashing because of the swscaler message seem to be a false route (why I messed around with compiling ffmpeg on the pi myself).

I'm okay at picking up breadcrumbs, and I know some C# on avr microcontrollers - but unfortunately I think this is probably beyond what I'm capable of. :(
Was hoping I could serve my dad with some slideshow rpi's (pictures and video) for a fair he is attending next weekend. Hmm, too bad - didn't came across an alternative yet.

root@raspberrypi:/home/service/src/pqiv# cat /proc/cpu/alignment
User:		6
System:		0 (0x0)
Skipped:	4
Half:		0
Word:		0
DWord:		0
Multi:		0
User faults:	3 (fixup+warn)

root@raspberrypi:/home/service/src/pqiv# dmesg
[14808.578385] Alignment trap: pqiv (1717) PC=0x6a8bfc68 Instr=0xf402602d Address=0x64811008 FSR 0x801
[14808.578452] Alignment trap: not handling instruction f402602d at [<6a8bfc68>]
[14808.578470] 8<--- cut here ---
[14808.581566] Unhandled fault: alignment exception (0x801) at 0x64811008
[14808.588231] pgd = 4027cbbc
[14808.591043] [64811008] *pgd=06a89835, *pte=11e6175f, *ppte=11e61c7f

[phillipberndt]

Well, if you're willing to look closer into this, we'll have to run pqiv (with debug symbols) in a debugger to see where in the code the sigbus happens. Do you know how to do that? (gdb --args ./pqiv file.mp4, r, bt once it crashes)

[BadlyDrawnBoy]

Hi, I will have a try but for now all my raspberrys are on the fair and I didn't manage to boot a virtual pi with qemu yet. I will come back to it at some point.

Schöne Grüße aus Bremen! :)