| From | Steve French <> | Date | Wed, 24 Jul 2019 15:49:32 -0500 | Subject | Re: [PATCH 5.2 038/413] signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig |
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Note that this patch causes a regression (removing cifs module fails, due to unmount leaking a thread with this change).
We are testing a workaround to cifs.ko which would be needed if this patch were to be backported.
On Wed, Jul 24, 2019 at 2:26 PM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > [ Upstream commit 72abe3bcf0911d69b46c1e8bdb5612675e0ac42c ] > > The locking in force_sig_info is not prepared to deal with a task that > exits or execs (as sighand may change). The is not a locking problem > in force_sig as force_sig is only built to handle synchronous > exceptions. > > Further the function force_sig_info changes the signal state if the > signal is ignored, or blocked or if SIGNAL_UNKILLABLE will prevent the > delivery of the signal. The signal SIGKILL can not be ignored and can > not be blocked and SIGNAL_UNKILLABLE won't prevent it from being > delivered. > > So using force_sig rather than send_sig for SIGKILL is confusing > and pointless. > > Because it won't impact the sending of the signal and and because > using force_sig is wrong, replace force_sig with send_sig. > > Cc: Namjae Jeon <namjae.jeon@samsung.com> > Cc: Jeff Layton <jlayton@primarydata.com> > Cc: Steve French <smfrench@gmail.com> > Fixes: a5c3e1c725af ("Revert "cifs: No need to send SIGKILL to demux_thread during umount"") > Fixes: e7ddee9037e7 ("cifs: disable sharing session and tcon and add new TCP sharing code") > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > fs/cifs/connect.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c > index 8dd6637a3cbb..714a359c7c8d 100644 > --- a/fs/cifs/connect.c > +++ b/fs/cifs/connect.c > @@ -2631,7 +2631,7 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect) > > task = xchg(&server->tsk, NULL); > if (task) > - force_sig(SIGKILL, task); > + send_sig(SIGKILL, task, 1); > } > > static struct TCP_Server_Info * > -- > 2.20.1 > > >
-- Thanks,
Steve
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