2010-03-31 12:19:19     Kernel Freeze maybe due to bfin_mac?

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2010-03-31 12:19:19     Kernel Freeze maybe due to bfin_mac?

Stefan Wanja (GERMANY)

Message: 87929   




I opened a new thread for an old problem because I fear that at the old thread noone looks anymore. It was this thread: https://blackfin.uclinux.org/gf/project/uclinux-dist/forum/?action=ForumBrowse&forum_id=39&thread_id=39883


Now we got us a gnICE+ debugger and now I can see a bit more.


Looking at the frozen board with bfin-elf-gdb the stack consists only of three entries (I repeated this on the bf527 EZKit a couple of times now):


    evt_timer() at /..../linux-2.6.x/arch/blackfin/include/asm/current.h:17

    bfin_mac_hard_start_xmit(skb=0x457288, dev=0x3d8b0a0) at drivers/net/bfin_mac.c:685



Looking at the memory there are zeros until 0x20400000, where the kernel begins, from there on its all 0xadadadad (or different at other times)


Looking at the registers there are only zeros except for






rets=0xd4eec <bfin_mac_hard_start_xmit+388>

pc= 0xd4eec <bfin_mac_hard_start_xmit+388>


Within bfin_mac_hard_start_xmit it stopped at the function call to blackfin_dcache_flush_range with parameter data being 0x0 (problably the value after the flush).


I don't know how the caching works, but we've had problems in the bfin_mac driver with caching before... I think there might be a bug in there.


Due to the yet unsolved older bug we (still) have WRITE_THROUGH cache policy in use as a work around, might be that the problem only occurs with that setting.


Kind Regards,






2010-03-31 17:23:47     Re: Kernel Freeze maybe due to bfin_mac?

Mike Frysinger (UNITED STATES)

Message: 87939   


dont post the same thing twice please