On Sun, 31 Dec 2006 13:11:26 -0800 Daniel Walker wrote: > On Sun, 2006-12-31 at 12:43 -0800, Randy Dunlap wrote: > > On Sun, 31 Dec 2006 11:45:09 -0800 Daniel Walker wrote: > > > > > On Sun, 2006-12-31 at 23:04 +0800, Fengguang Wu wrote: > > > > Hi, > > > > > > > > The following messages keeps popping up when CONFIG_PROFILE_LIKELY=y: > > > > > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > init[1]: segfault at ffffffff8118c110 rip ffffffff8118c110 rsp > > > > 00007fff9a9d14d8 error 15 > > > > > > > > > > > > > Does this seem like an appropriate solution? This just reconstitutes > > > Ingo's patch by removing the unlikely calls that got added recently. > > > > How does this fix the problem? (if it does) > > What is the real cause of the problem? > > Well I tested it so I sure hope it fixes it (unless I've gone mad). I > guess we can wait for Fengguang to test it tho.
Yes, it fixed it in my testing also. > > > Maybe a comment into vsyscall.c that says to stay away from all macro's > > > and possible debug code that could be added might be helpful ? > > > > Why? > > I don't know very much about vsyscalls, but from what I've read they > actually reside in userspace. So with and "unlikely" added into that > code, and profiling on, you will end up calling do_check_likely() which > is in kernel space that's how the segfault happens. > > I imagine this goes for all debugging in kernel space, you can't add it > into a vsyscall. That's my reasoning behind adding a comment. OK, thanks. The first explanation was a bit lacking IMO, but this one begins to help. --- ~Randy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
