> Sorry to interrupt as I am really confused here: > If it's a copyin case, has the page been mapped for the current process?
Yes. The kernel has the current process mapped to the low address range and code like get_user(), put_user() "simply" reaches down to those addresses (maybe not so simply, as the access needs to be within a STAC/CLAC section of code on modern CPUs, and the access instruction needs an entry in EXTABLE so that the page fault handler can fix it if there isn't a page mapped at the user address). > will memory_failure() find it and unmap it? if succeed, then the current will > be > signaled with correct vaddr and shift? That's a very good question. I didn't see a SIGBUS when I first wrote this code, hence all the p->mce_vaddr. But now I'm a) not sure why there wasn't a signal b) if we are to fix the problems noted by AndyL, need to make sure that there isn't a SIGBUS > Maybe the mce_vaddr is set correctly, but we may lost the correct page shift? Yes. There is a hard-coded PAGE_SHIFT for this case - which may not match the actual page size. > And for copyin case, we don't need to call set_mce_nospec()? Yes. We should. Thanks for your good questions. -Tony
