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authorPaolo Abeni <pabeni@redhat.com>2023-10-11 10:20:55 +0300
committerJakub Kicinski <kuba@kernel.org>2023-10-14 02:49:32 +0300
commit419ce133ab928ab5efd7b50b2ef36ddfd4eadbd2 (patch)
tree8d934593e6eaf8f7ded2c7c32e8bd0db8effccd9 /include
parent242e34500a32631f85c2b4eb6cb42a368a39e54f (diff)
downloadlinux-419ce133ab928ab5efd7b50b2ef36ddfd4eadbd2.tar.xz
tcp: allow again tcp_disconnect() when threads are waiting
As reported by Tom, .NET and applications build on top of it rely on connect(AF_UNSPEC) to async cancel pending I/O operations on TCP socket. The blamed commit below caused a regression, as such cancellation can now fail. As suggested by Eric, this change addresses the problem explicitly causing blocking I/O operation to terminate immediately (with an error) when a concurrent disconnect() is executed. Instead of tracking the number of threads blocked on a given socket, track the number of disconnect() issued on such socket. If such counter changes after a blocking operation releasing and re-acquiring the socket lock, error out the current operation. Fixes: 4faeee0cf8a5 ("tcp: deny tcp_disconnect() when threads are waiting") Reported-by: Tom Deseyn <tdeseyn@redhat.com> Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1886305 Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/f3b95e47e3dbed840960548aebaa8d954372db41.1697008693.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/net/sock.h10
1 files changed, 4 insertions, 6 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index b770261fbdaf..92f7ea62a915 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -336,7 +336,7 @@ struct sk_filter;
* @sk_cgrp_data: cgroup data for this cgroup
* @sk_memcg: this socket's memory cgroup association
* @sk_write_pending: a write to stream socket waits to start
- * @sk_wait_pending: number of threads blocked on this socket
+ * @sk_disconnects: number of disconnect operations performed on this sock
* @sk_state_change: callback to indicate change in the state of the sock
* @sk_data_ready: callback to indicate there is data to be processed
* @sk_write_space: callback to indicate there is bf sending space available
@@ -429,7 +429,7 @@ struct sock {
unsigned int sk_napi_id;
#endif
int sk_rcvbuf;
- int sk_wait_pending;
+ int sk_disconnects;
struct sk_filter __rcu *sk_filter;
union {
@@ -1189,8 +1189,7 @@ static inline void sock_rps_reset_rxhash(struct sock *sk)
}
#define sk_wait_event(__sk, __timeo, __condition, __wait) \
- ({ int __rc; \
- __sk->sk_wait_pending++; \
+ ({ int __rc, __dis = __sk->sk_disconnects; \
release_sock(__sk); \
__rc = __condition; \
if (!__rc) { \
@@ -1200,8 +1199,7 @@ static inline void sock_rps_reset_rxhash(struct sock *sk)
} \
sched_annotate_sleep(); \
lock_sock(__sk); \
- __sk->sk_wait_pending--; \
- __rc = __condition; \
+ __rc = __dis == __sk->sk_disconnects ? __condition : -EPIPE; \
__rc; \
})