Re: [PATCH] Set TIF_IRET in more places

From: Ulrich Drepper (drepper@redhat.com)
Date: Mon Jan 06 2003 - 13:42:11 EST


Luca Barbieri wrote:

> 1. vfork seems to not set any TIF_ flags so a ptracer setting regs
> while a vforking task is stopped in ptrace_notify called from vfork
> would result in clobbered %ecx and %edx.

Just to be clear: the vfork syscall does not use sysenter. It's not
possible with the current implementation. The magic sysenter wrapping
code would have to recognize the syscall and handle it special by saving
the return address. From glibc's POV the %edx register would be free
but I consider this interface far to fragile.

-- 
--------------.                        ,-.            444 Castro Street
Ulrich Drepper \    ,-----------------'   \ Mountain View, CA 94041 USA
Red Hat         `--' drepper at redhat.com `---------------------------

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Tue Jan 07 2003 - 22:00:32 EST