Daniel Jordan <[email protected]> writes: > On Tue, Feb 26, 2019 at 02:49:05PM +0800, Huang, Ying wrote: >> Do you have time to take a look at this patch? > > Hi Ying, is this handling all places where swapoff might cause a task to read > invalid data? For example, why don't other reads of swap_map (for example > swp_swapcount, page_swapcount, swap_entry_free) need to be synchronized like > this?
I have checked these places. They are safe because there are some locks (like page lock, page table lock, etc.) held to prevent swapoff. I found another place in the kernel that is unsafe: the mincore. I have a patch for that and will post it (in fact again) after this one is merged. Best Regards, Huang, Ying
