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| author | Jon Paul Maloy <jon.maloy@ericsson.com> | 2017-05-11 21:28:15 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-05-12 05:19:30 +0300 |
| commit | 844cf763fba654436d3a4279b6a672c196cf1901 (patch) | |
| tree | 60dc21eb9e82310b9267805b12f88fa07ae9f925 | |
| parent | ad990dbe6d3ac3af1f5f4484b1126b9fc601e98a (diff) | |
| download | linux-844cf763fba654436d3a4279b6a672c196cf1901.tar.xz | |
tipc: make macro tipc_wait_for_cond() smp safe
The macro tipc_wait_for_cond() is embedding the macro sk_wait_event()
to fulfil its task. The latter, in turn, is evaluating the stated
condition outside the socket lock context. This is problematic if
the condition is accessing non-trivial data structures which may be
altered by incoming interrupts, as is the case with the cong_links()
linked list, used by socket to keep track of the current set of
congested links. We sometimes see crashes when this list is accessed
by a condition function at the same time as a SOCK_WAKEUP interrupt
is removing an element from the list.
We fix this by expanding selected parts of sk_wait_event() into the
outer macro, while ensuring that all evaluations of a given condition
are performed under socket lock protection.
Fixes: commit 365ad353c256 ("tipc: reduce risk of user starvation during link congestion")
Reviewed-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/tipc/socket.c | 38 |
1 files changed, 19 insertions, 19 deletions
diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 0d4f2f455a7c..1b92b72e812f 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -362,25 +362,25 @@ static int tipc_sk_sock_err(struct socket *sock, long *timeout) return 0; } -#define tipc_wait_for_cond(sock_, timeout_, condition_) \ -({ \ - int rc_ = 0; \ - int done_ = 0; \ - \ - while (!(condition_) && !done_) { \ - struct sock *sk_ = sock->sk; \ - DEFINE_WAIT_FUNC(wait_, woken_wake_function); \ - \ - rc_ = tipc_sk_sock_err(sock_, timeout_); \ - if (rc_) \ - break; \ - prepare_to_wait(sk_sleep(sk_), &wait_, \ - TASK_INTERRUPTIBLE); \ - done_ = sk_wait_event(sk_, timeout_, \ - (condition_), &wait_); \ - remove_wait_queue(sk_sleep(sk_), &wait_); \ - } \ - rc_; \ +#define tipc_wait_for_cond(sock_, timeo_, condition_) \ +({ \ + struct sock *sk_; \ + int rc_; \ + \ + while ((rc_ = !(condition_))) { \ + DEFINE_WAIT_FUNC(wait_, woken_wake_function); \ + sk_ = (sock_)->sk; \ + rc_ = tipc_sk_sock_err((sock_), timeo_); \ + if (rc_) \ + break; \ + prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE); \ + release_sock(sk_); \ + *(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \ + sched_annotate_sleep(); \ + lock_sock(sk_); \ + remove_wait_queue(sk_sleep(sk_), &wait_); \ + } \ + rc_; \ }) /** |