Kirill Korotaev wrote: > Jes Sorensen wrote: >> If you hit this, yes I'd insert the BUG_ON in your test kernel and fix >> the code. Maybe add the BUG_ON in upstream for CONFIG_DEBUG or >> something. > I guess then all the platforms should be analyzed/patched carefully > or all the callers of virt_to_page(). > Care to create debug patch? Well you suggested a patch which just hides the problem. I suggest you change it to have the BUG_ON(). >> Which callers did you see cause this? If it was a common problem I would >> expect a lot of data corruption or crashes on ia64 systems which I >> haven't heard of. > from the patch: > pte_alloc_one() calls pgtable_quicklist_alloc() which can return NULL in > case of allocation failure. > > It was hit on OpenVZ where kernel memory is accounted and limited on > per-container basis (it is possible to DoS using page tables allocations). > In mainstream the bug can be hit if OOM killer > kills the process and __get_free_page() returns NULL which is rare, but still possible. I see, since you have it tracked down, it would be good to fix it and push a patch upstream. Unless of course Andrew or Linus thinks this is the wrong approach. Cheers, Jes - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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