| Message ID | 20240207233856.161916-1-allison.henderson@oracle.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v3,1/1] net:rds: Fix possible deadlock in rds_message_put | expand |
在 2024/2/8 7:38, allison.henderson@oracle.com 写道: > From: Allison Henderson <allison.henderson@oracle.com> > > 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) A trivial problem, Based on the file https://www.kernel.org/doc/Documentation/process/submitting-patches.rst, Fixes tag should be the following? Fixes: bdbe6fbc6a2f ("RDS: recv.c") Thanks, Zhu Yanjun > Reported-by: syzbot+f9db6ff27b9bfdcfeca0@syzkaller.appspotmail.com > Reported-by: syzbot+dcd73ff9291e6d34b3ab@syzkaller.appspotmail.com > > Signed-off-by: Allison Henderson <allison.henderson@oracle.com> > --- > net/rds/recv.c | 13 +++++++++++-- > 1 file 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); > } > > /*
On Thu, 2024-02-08 at 15:37 +0800, Zhu Yanjun wrote: > 在 2024/2/8 7:38, allison.henderson@oracle.com 写道: > > From: Allison Henderson <allison.henderson@oracle.com> > > > > 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) > > A trivial problem, > Based on the file > https://urldefense.com/v3/__https://www.kernel.org/doc/Documentation/process/submitting-patches.rst__;!!ACWV5N9M2RV99hQ!MiEeS6J7X92LD8hhF5jHl882A8vJtDEXfxPdBG3cmE7Qhsic--cSQKgEbPDF1W-i_ZXdM64n5coFpc1xEIOZWmFhoubN$ > , > Fixes tag should be the following? > > Fixes: bdbe6fbc6a2f ("RDS: recv.c") Ah, I had missed the quotations. Will update. Thanks for the review! Allison > > Thanks, > Zhu Yanjun > > > Reported-by: syzbot+f9db6ff27b9bfdcfeca0@syzkaller.appspotmail.com > > Reported-by: syzbot+dcd73ff9291e6d34b3ab@syzkaller.appspotmail.com > > > > Signed-off-by: Allison Henderson <allison.henderson@oracle.com> > > --- > > net/rds/recv.c | 13 +++++++++++-- > > 1 file 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); > > } > > > > /* >
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); } /*