Messages in this thread | | | Date | Mon, 5 Jul 2010 11:23:13 -0700 (PDT) | From | Davide Libenzi <> | Subject | Re: [PATCH] signalfd: fill in ssi_int for posix timers and message queues |
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On Mon, 5 Jul 2010, Nathan Lynch wrote:
> Hello Davide, > > On Sat, 2010-07-03 at 12:09 -0700, Davide Libenzi wrote: > > On Fri, 2 Jul 2010, Nathan Lynch wrote: > > > > > If signalfd is used to consume a signal generated by a POSIX interval > > > timer or POSIX message queue, the ssi_int field does not reflect the > > > data (sigevent->sigev_value) supplied to timer_create(2) or > > > mq_notify(3). (The ssi_ptr field, however, is filled in.) > > > > > > This behavior differs from signalfd's treatment of sigqueue-generated > > > signals -- see the default case in signalfd_copyinfo. It also gives > > > results that differ from the case when a signal is handled > > > conventionally via a sigaction-registered handler. > > > > > > So, set signalfd_siginfo->ssi_int in the remaining cases (__SI_TIMER, > > > __SI_MESGQ) where ssi_ptr is set. > > > > > > Signed-off-by: Nathan Lynch <ntl@pobox.com> > > > --- > > > fs/signalfd.c | 2 ++ > > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > > > diff --git a/fs/signalfd.c b/fs/signalfd.c > > > index f329849..1c5a6ad 100644 > > > --- a/fs/signalfd.c > > > +++ b/fs/signalfd.c > > > @@ -88,6 +88,7 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, > > > err |= __put_user(kinfo->si_tid, &uinfo->ssi_tid); > > > err |= __put_user(kinfo->si_overrun, &uinfo->ssi_overrun); > > > err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr); > > > + err |= __put_user(kinfo->si_int, &uinfo->ssi_int); > > > break; > > > case __SI_POLL: > > > err |= __put_user(kinfo->si_band, &uinfo->ssi_band); > > > @@ -111,6 +112,7 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, > > > err |= __put_user(kinfo->si_pid, &uinfo->ssi_pid); > > > err |= __put_user(kinfo->si_uid, &uinfo->ssi_uid); > > > err |= __put_user((long) kinfo->si_ptr, &uinfo->ssi_ptr); > > > + err |= __put_user(kinfo->si_int, &uinfo->ssi_int); > > > break; > > > default: > > > > I am fine with it, but I now noticed that signalfd_copyinfo() got out of > > sync from copy_siginfo_to_user(), which should match. > > Do you mind aligning that too, as part of your patch? > > An adding a comment on the lines of the one in copy_siginfo_to_user() to > > signalfd_copyinfo() too? > > Sorry, I'm not sure I understand. Are you saying that > copy_siginfo_to_user should have analogous lines added to assign to > si_int? That's actually not necessary if I read the code correctly: in > struct siginfo, si_ptr and si_int are members of a sigval union, so > assigning to the former covers the latter. signalfd must assign both > ssi_ptr and ssi_int since they occupy different locations in > signalfd_siginfo. > > Perhaps the attached testcases make the problem (as I see it) more > clear? The final assertion fails without this patch.
Sorry, my bad. I had forgotten that siginfo had them in a union, so the different code in signalfd_copyinfo() is needed. Patch looks fine to me as is.
- Davide
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