Messages in this thread | | | Date | Tue, 31 Jul 2007 04:11:17 +0400 | From | Oleg Nesterov <> | Subject | Re: [PATCH] Use ERESTARTNOHAND if poll() is interrupted by a signal |
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On 07/30, Andrew Morton wrote: > > On Sun, 29 Jul 2007 19:05:05 +0200 > Manfred Spraul <manfred@colorfullife.com> wrote: > > > Hi Andrew, > > > > poll() returns -EINTR if a signal is pending. > > EINTR is a bad choice: it means that poll returns to user space if the > > task is stopped by SIGSTOP/SIGCONT or by the freezer. > > select() and ppoll() both use ERESTARTNOHAND, this avoids a return to > > user space for signals that are handled by the kernel. > > > > The patch switches poll() to ERESTARTNOHAND. > > Tested with FC6. Patch against 2.6.23-rc1-mm1. > > hm. Is this a fix against > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.23-rc1/2.6.23-rc1-mm1/broken-out/do_poll-return-eintr-when-signalled.patch > only, or does mainline also need fixing?
That patch doesn't (at least shouldn't) change the behaviour.
> I guess the consequences of the thing-which-this-fixes aren't huge, s I ca > queue this up for 2.6.24, after Oleg's > do_poll-return-eintr-when-signalled.patch? > > > Signed-off-by: Manfred Spraul <manfred@colorfullife.com> > > > > --- 2.6/fs/select.c 2007-07-28 20:31:51.000000000 +0200 > > +++ build-2.6/fs/select.c 2007-07-28 21:21:52.000000000 +0200 > > @@ -621,7 +621,7 @@ static int do_poll(unsigned int nfds, s > > if (!count) { > > count = wait->error; > > if (signal_pending(current)) > > - count = -EINTR; > > + count = -ERESTARTNOHAND;
I am not sure. This means we restart sys_poll() with the same timeout if there is no pending signal. I think we need ERESTART_RESTARTBLOCK logic.
Oleg.
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