cvs commit: src/sys/kern kern_sig.c

[David Xu]

On Saturday 21 October 2006 00:19, John Baldwin wrote:
> jhb         2006-10-20 16:19:21 UTC
>
>   FreeBSD src repository
>
>   Modified files:
>     sys/kern             kern_sig.c
>   Log:
>   Remove the check that prevented signals from being delivered to exiting
>   processes.  It was originally added back when support for Linux threads
>   (and thus shared sigacts objects) was added, but no one knows why.  My
>   guess is that at some point during the Linux threads patches, the sigacts
>   object was torn down during exit1(), so this check was added to prevent
>   a panic for that race.  However, the stuff that was actually committed to
>   the tree doesn't teardown sigacts until wait() making the above race
> moot. Re-allowing signals here lets one interrupt a NFS request during
> process teardown (such as closing descriptors) on an interruptible mount.
>
>   Requested by:   kib (long time ago)
>   MFC after:      1 week
>
>   Revision  Changes    Path
>   1.333     +1 -3      src/sys/kern/kern_sig.c
This commit opens a window that may cause memory leak, since we have
signal queue in -CURRENT now, signal queue uses memory, before this
change, the P_WEXIT will prevents new signal to be queued, after the
flag is set in kern_exit, we call signqueue_flush to free memory. I think
we should move sigqueue_flush down to a safe point where the
PROC lock is no longer unlocked or move it to a place after p_state is set
to PRS_ZOMBIE.

David Xu