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authorAllison Henderson <allison.henderson@oracle.com>2024-02-08 19:28:54 -0700
committerPaolo Abeni <pabeni@redhat.com>2024-02-13 10:25:30 +0100
commitf1acf1ac84d2ae97b7889b87223c1064df850069 (patch)
tree494b780f4ed692eccf50eb7e9a136bb3e31f02a6 /net
parent9f30831390ede02d9fcd54fd9ea5a585ab649f4a (diff)
net:rds: Fix possible deadlock in rds_message_put
Functions rds_still_queued and rds_clear_recv_queue lock a given socket in order to safely iterate over the incoming rds messages. However calling rds_inc_put while under this lock creates a potential deadlock. rds_inc_put may eventually call rds_message_purge, which will lock m_rs_lock. This is the incorrect locking order since m_rs_lock is meant to be locked before the socket. To fix this, we move the message item to a local list or variable that wont need rs_recv_lock protection. Then we can safely call rds_inc_put on any item stored locally after rs_recv_lock is released. Fixes: bdbe6fbc6a2f ("RDS: recv.c") Reported-by: syzbot+f9db6ff27b9bfdcfeca0@syzkaller.appspotmail.com Reported-by: syzbot+dcd73ff9291e6d34b3ab@syzkaller.appspotmail.com Signed-off-by: Allison Henderson <allison.henderson@oracle.com> Link: https://lore.kernel.org/r/20240209022854.200292-1-allison.henderson@oracle.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
-rw-r--r--net/rds/recv.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/net/rds/recv.c b/net/rds/recv.c
index c71b923764fd..5627f80013f8 100644
--- a/net/rds/recv.c
+++ b/net/rds/recv.c
@@ -425,6 +425,7 @@ static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
struct sock *sk = rds_rs_to_sk(rs);
int ret = 0;
unsigned long flags;
+ struct rds_incoming *to_drop = NULL;
write_lock_irqsave(&rs->rs_recv_lock, flags);
if (!list_empty(&inc->i_item)) {
@@ -435,11 +436,14 @@ static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
-be32_to_cpu(inc->i_hdr.h_len),
inc->i_hdr.h_dport);
list_del_init(&inc->i_item);
- rds_inc_put(inc);
+ to_drop = inc;
}
}
write_unlock_irqrestore(&rs->rs_recv_lock, flags);
+ if (to_drop)
+ rds_inc_put(to_drop);
+
rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
return ret;
}
@@ -758,16 +762,21 @@ void rds_clear_recv_queue(struct rds_sock *rs)
struct sock *sk = rds_rs_to_sk(rs);
struct rds_incoming *inc, *tmp;
unsigned long flags;
+ LIST_HEAD(to_drop);
write_lock_irqsave(&rs->rs_recv_lock, flags);
list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
-be32_to_cpu(inc->i_hdr.h_len),
inc->i_hdr.h_dport);
+ list_move(&inc->i_item, &to_drop);
+ }
+ write_unlock_irqrestore(&rs->rs_recv_lock, flags);
+
+ list_for_each_entry_safe(inc, tmp, &to_drop, i_item) {
list_del_init(&inc->i_item);
rds_inc_put(inc);
}
- write_unlock_irqrestore(&rs->rs_recv_lock, flags);
}
/*