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authorJon Paul Maloy <jon.maloy@ericsson.com>2017-05-11 20:28:15 +0200
committerDavid S. Miller <davem@davemloft.net>2017-05-11 22:19:30 -0400
commit844cf763fba654436d3a4279b6a672c196cf1901 (patch)
tree60dc21eb9e82310b9267805b12f88fa07ae9f925
parentad990dbe6d3ac3af1f5f4484b1126b9fc601e98a (diff)
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.c38
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_; \
})
/**