On Thu 23-01-20 19:10:47, Andrew Morton wrote: > On Mon, 20 Jan 2020 08:29:39 +0100 Michal Hocko <[email protected]> wrote: > > > On Mon 20-01-20 10:33:14, Pingfan Liu wrote: > > > After commit ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug"), > > > when a mem section is fully deactivated, section_mem_map still records the > > > section's start pfn, which is not used any more and will be reassigned > > > during re-added. > > > > > > In analogy with alloc/free pattern, it is better to clear all fields of > > > section_mem_map. > > > > > > Beside this, it breaks the user space tool "makedumpfile" [1], which makes > > > assumption that a hot-removed section has mem_map as NULL, instead of > > > checking directly against SECTION_MARKED_PRESENT bit. (makedumpfile will > > > be > > > better to change the assumption, and need a patch) > > > > > > The bug can be reproduced on IBM POWERVM by "drmgr -c mem -r -q 5" , > > > trigger a crash, and save vmcore by makedumpfile > > > > While makedumpfile lives very closely to the kernel and occasional > > breakage is to be expected I still believe that Fixes: ba72b4c8cf60 > > is due. > > But not a cc:stable?
Well, I wouldn't say this is really critical. makedumpfile will get its fix... But if people think it would be useful in stable I won't oppose. -- Michal Hocko SUSE Labs _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
