Messages in this thread Patch in this message | | | Date | Thu, 8 Nov 2007 20:36:04 -0800 | From | Andrew Morton <> | Subject | Re: [patch 2/2] clone: prepare to recycle CLONE_DETACHED and CLONE_STOPPED |
| |
> On Thu, 08 Nov 2007 13:31:43 -0800 akpm@linux-foundation.org wrote: > From: Andrew Morton <akpm@linux-foundation.org> > > Ulrich says that we never used these clone flags and that nothing should be > using them. > > As we're down to only a single bit left in clone's flags argument, let's add a > warning to check that no userspace is actually using these. Hopefully we will > be able to recycle them. > > Cc: Ulrich Drepper <drepper@redhat.com> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Roland McGrath <roland@redhat.com> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > --- > > kernel/fork.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > diff -puN kernel/fork.c~clone-prepare-to-recycle-clone_detached-and-clone_stopped kernel/fork.c > --- a/kernel/fork.c~clone-prepare-to-recycle-clone_detached-and-clone_stopped > +++ a/kernel/fork.c > @@ -1420,10 +1420,18 @@ long do_fork(unsigned long clone_flags, > int trace = 0; > long nr; > > - if (unlikely(current->ptrace)) { > - trace = fork_traceflag (clone_flags); > - if (trace) > - clone_flags |= CLONE_PTRACE; > + /* > + * We hope to recycle these flags after 2.6.26 > + */ > + if (unlikely(clone_flags & (CLONE_DETACHED|CLONE_STOPPED))) { > + if (printk_ratelimit()) { > + char comm[TASK_COMM_LEN]; > + > + printk(KERN_INFO "fork(): process `%s' used deprecated " > + "clone flags 0x%lx\n", > + get_task_comm(comm, current), > + clone_flags & (CLONE_DETACHED|CLONE_STOPPED)); > + } > } > > p = copy_process(clone_flags, stack_start, regs, stack_size,
That was all screwed up. Better version:
From: Andrew Morton <akpm@linux-foundation.org>
Ulrich says that we never used these clone flags and that nothing should be using them.
As we're down to only a single bit left in clone's flags argument, let's add a warning to check that no userspace is actually using these. Hopefully we will be able to recycle them.
Roland said:
CLONE_STOPPED was previously used by some NTPL versions when under thread_db (i.e. only when being actively debugged by gdb), but not for a long time now, and it never worked reliably when it was used. Removing it seems fine to me.
Cc: Ulrich Drepper <drepper@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
kernel/fork.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff -puN kernel/fork.c~clone-prepare-to-recycle-clone_detached-and-clone_stopped kernel/fork.c --- a/kernel/fork.c~clone-prepare-to-recycle-clone_detached-and-clone_stopped +++ a/kernel/fork.c @@ -1420,6 +1420,23 @@ long do_fork(unsigned long clone_flags, int trace = 0; long nr; + /* + * We hope to recycle these flags after 2.6.26 + */ + if (unlikely(clone_flags & (CLONE_DETACHED|CLONE_STOPPED))) { + static int __read_mostly count = 100; + + if (count && printk_ratelimit()) { + char comm[TASK_COMM_LEN]; + + count--; + printk(KERN_INFO "fork(): process `%s' used deprecated " + "clone flags 0x%lx\n", + get_task_comm(comm, current), + clone_flags & (CLONE_DETACHED|CLONE_STOPPED)); + } + } + if (unlikely(current->ptrace)) { trace = fork_traceflag (clone_flags); if (trace) _ - 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/
| |