On Mon, Feb 20, 2017 at 05:00:17AM +0000, Horiguchi Naoya(堀口 直也) wrote: > On Tue, Feb 14, 2017 at 04:41:29PM +0100, Jan Stancek wrote: > > Hi, > > > > code below (and LTP madvise07 [1]) doesn't produce SIGBUS, > > unless I touch/prefault page before call to madvise(). > > > > Is this expected behavior? > > Thank you for reporting. > > madvise(MADV_HWPOISON) triggers page fault when called on the address > over which no page is faulted-in, so I think that SIGBUS should be > called in such case. > > But it seems that memory error handler considers such a page as "reserved > kernel page" and recovery action fails (see below.) > > [ 383.371372] Injecting memory failure for page 0x1f10 at 0x7efcdc569000 > [ 383.375678] Memory failure: 0x1f10: reserved kernel page still referenced by 1 users > [ 383.377570] Memory failure: 0x1f10: recovery action for reserved kernel page: Failed > > I'm not sure how/when this behavior was introduced, so I try to understand. I found that this is a zero page, which is not recoverable for memory error now. > IMO, the test code below looks valid to me, so no need to change. I think that what the testcase effectively does is to test whether memory handling on zero pages works or not. And the testcase's failure seems acceptable, because it's simply not-implemented yet. Maybe recovering from error on zero page is possible (because there's no data loss for memory error,) but I'm not sure that code might be simple enough and/or it's worth doing ... Thanks, Naoya Horiguchi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href
