Messages in this thread |  | | Subject | Re: [PATCH] Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" | From | Manfred Spraul <> | Date | Wed, 18 Dec 2019 20:25:03 +0100 |
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Hello together,
On 12/17/19 10:17 PM, Herton R. Krzesinski wrote: > On Mon, Dec 16, 2019 at 08:04:53PM +0100, Manfred Spraul wrote: >> Hi Ioanna, >> >> On 12/11/19 8:13 PM, Ioanna Alifieraki wrote: >> >>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1694779 >>> >>> Fixes: a97955844807 ("ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()") >>> Signed-off-by: Ioanna Alifieraki <ioanna-maria.alifieraki@canonical.com> >> Acked-by: Manfred Spraul <manfred@colorfullife.com> > Acked-by: Herton R. Krzesinski <herton@redhat.com>
What I forgot:
I think Cc: stable@vger.kernel.org should be added:
The change is obviously correct, it fixes a real issue.
>>> --- >>> ipc/sem.c | 6 ++---- >>> 1 file changed, 2 insertions(+), 4 deletions(-) >>> >>> diff --git a/ipc/sem.c b/ipc/sem.c >>> index ec97a7072413..fe12ea8dd2b3 100644 >>> --- a/ipc/sem.c >>> +++ b/ipc/sem.c >>> @@ -2368,11 +2368,9 @@ void exit_sem(struct task_struct *tsk) >>> ipc_assert_locked_object(&sma->sem_perm); >>> list_del(&un->list_id); >>> - /* we are the last process using this ulp, acquiring ulp->lock >>> - * isn't required. Besides that, we are also protected against >>> - * IPC_RMID as we hold sma->sem_perm lock now >>> - */ >>> + spin_lock(&ulp->lock); >>> list_del_rcu(&un->list_proc); >>> + spin_unlock(&ulp->lock); >>> /* perform adjustments registered in un */ >>> for (i = 0; i < sma->sem_nsems; i++) { >>
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