-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2011-07-15 15:10, Jan Kiszka wrote: > But... right now it looks like we found our primary regression: > "nucleus/shadow: shorten the uninterruptible path to secondary mode". > It opens a short windows during relax where the migrated task may be > active under both schedulers. We are currently evaluating a revert > (looks good so far), and I need to work out my theory in more > details.
Looks like this commit just made a long-standing flaw in Xenomai's interrupt handling more visible: We reschedule over the interrupt stack in the Xenomai interrupt handler tails, at least on x86-64. Not sure if other archs have interrupt stacks, the point is Xenomai's design wrongly assumes there are no such things. We were lucky so far that the values saved on this shared stack were apparently "compatible", means we were overwriting them with identical or harmless values. But that's no longer true when interrupts are hitting us in the xnpod_suspend_thread path of a relaxing shadow. Likely the only possible fix is establishing a reschedule hook for Xenomai in the interrupt exit path after the original stack is restored - - just like Linux works. Requires changes to both ipipe and Xenomai unfortunately. Jan -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk4hSDsACgkQitSsb3rl5xSmOACfbZfcNKyO9YDvPE+R5H75d0ky DX0An32BrZW+lpEnxnLLCHSQ5r8itnE9 =n6u8 -----END PGP SIGNATURE----- _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
