Commit-ID: 7cf7db8df0b78076eafa4ead47559344ca7b7a43 Gitweb: http://git.kernel.org/tip/7cf7db8df0b78076eafa4ead47559344ca7b7a43 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Thu, 10 Dec 2009 00:53:21 +0000 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitDate: Thu, 10 Dec 2009 23:04:11 +0100 signals: Fix more rcu assumptions 1) Remove the misleading comment in __sigqueue_alloc() which claims that holding a spinlock is equivalent to rcu_read_lock(). 2) Add a rcu_read_lock/unlock around the __task_cred() access in __sigqueue_alloc() This needs to be revisited to remove the remaining users of read_lock(&tasklist_lock) but that's outside the scope of this patch. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> LKML-Reference: <20091210004703.269843657@xxxxxxxxxxxxx> --- kernel/signal.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 7331656..f67545f 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -218,13 +218,13 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi struct user_struct *user; /* - * We won't get problems with the target's UID changing under us - * because changing it requires RCU be used, and if t != current, the - * caller must be holding the RCU readlock (by way of a spinlock) and - * we use RCU protection here + * Protect access to @t credentials. This can go away when all + * callers hold rcu read lock. */ + rcu_read_lock(); user = get_uid(__task_cred(t)->user); atomic_inc(&user->sigpending); + rcu_read_unlock(); if (override_rlimit || atomic_read(&user->sigpending) <= -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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