On Fri, May 18, 2012 at 11:05:46AM -0700, Grant Grundler wrote: > On Fri, May 18, 2012 at 10:58 AM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > ... > >?Except for that mess with multiple > > pending signals, the value we have in r28 on syscall entry doesn't > > seem to affect the syscall behaviour... ?Some HPUX compat fun? > > We stopped trying to support HPUX compat support probably 8 or so > years ago. Since HP didn't care, no one else did either. So no need > to consider it now. In any case, it doesn't look like something that might be HPUX-related - there r28 is not used for arguments or syscall number either, as far as I can tell... That's a side story, in any case; whatever the reason for restoring r28, it only masks the bug with double restarts. If you enter syscall with r28 equal to e.g. -ERESTARTNOINTR, get the same value from sys_whatever() and have a couple of pending signals, you will have syscall_restart() called twice, each time seeing regs->gr[28] == -ERESTARTNOINTR and leaving it unchanged. regs->gr[31] will be decremented by 8 on each of those calls, first time back to your syscall (correctly), then to the entry point of the first handler minus 8. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
