On Fri, 2011-07-15 at 16:38 +0800, MailingLists wrote: > A page could be set to read only by the kernel (supervisor in the > powerpc > literature) on the e500, and that's what the kernel do. Set > SW(supervisor > write) bit in the TLB entry to grant write permission to the kernel on > a > page. > > And further the SW bit is set according to the DIRTY flag of the PTE, > PTE.DIRTY is set in the do_page_fault(), the futex_lock_pi() disabled > page fault, the PTE.DIRTY never can be set, so do the SW bit, > unbreakable > COW occurred, infinite loop followed.
That would be it ... the SW dirty and young tracking relies on faults to fixup things in handle_pte_fault(). If the "disable page fault" thingy happens before we get there, then we have a pretty nasty bug. Note that this will hit more than just e500 (and in fact any architecture that relies on SW to do dirty and young tracking). Cheers, Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
