Fiasco.OC: null-pointer dereference?

Leslie Zhai lesliezhai at
Thu Jun 8 04:18:00 CEST 2017

Hi Matthias,

Thank you so much for your pretty cool 

Jean taught me about how to debug L4Re using jdb in qemu it 
used a on purpose bug (null ptr deref) to crash Ned, then L4Re thrown: 
unhandled write page fault at 0x0 pc=0x100398d, and addr2line ... -e ned 
-a 100398d to indicate the root cause line.

But how to find out the root cause if unclear that which components 
bring in the issue? just like Jean investigated why 
framebuffer-example-x86 failed to work, actually it is not init process 
issue, but Fiasco `_quota` member of a thread is not correctly 
initialized. 0001-Fix-invalid-initialization-in-new.patch is awesome! 
how to debug deepinto it? it might be easy to a maintainer of Fiasco 
kernel, but it is really magic to me :)

The same story is how to debug L4Linux? please 
give me some advice, thanks a lot!

Leslie Zhai - a LLVM hacker

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