On Fri, Feb 07, 2020 at 08:44:15PM -0800, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > > There was no protection against a corrupted struct page having an > implausible compound_head(). Sanity check that a compound page has > a head within reach of the maximum allocatable page (this will need > to be adjusted if one of the plans to allocate 1GB pages comes to > fruition). In addition, > > - Print the mapping pointer using %p insted of %px. The actual value of > the pointer can be read out of the raw page dump and using %p gives a > chance to correlate it with an earlier printk of the mapping pointer > - Print the mapping pointer from the head page, not the tail page > (the tail ->mapping pointer may be in use for other purposes, eg part > of a list_head) > - Print the order of the page for compound pages > - Dump the raw head page as well as the raw page > - Print the refcount from the head page, not the tail page > > Suggested-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Co-developed-by: John Hubbard <jhubbard@xxxxxxxxxx> > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> John, in comparison to the patch I sent earlier today, this version changes: - Reorder the things printed in the compound case so that all the information which is printed for non-compound pages is printed first - Removed inconsistent space between "compound_mapcount:" and the value - Print the refcount of the head page instead of the tail (which was the point of your patch!) - Print the mapping of the head instead of the tail - Don't dump the raw head if the page passed in was the head page
