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| author | Ilya Dryomov <idryomov@gmail.com> | 2019-01-14 21:13:10 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-02-15 08:07:39 +0100 |
| commit | f3f0a9d17f2a6ed44e0813084efecfd9afdcb90e (patch) | |
| tree | f2ab3064e02cc6883adce68e2433366ee99e04a0 | |
| parent | 80000148ea5862674bcd7002c12e6066f497babe (diff) | |
| download | linux-f3f0a9d17f2a6ed44e0813084efecfd9afdcb90e.tar.gz linux-f3f0a9d17f2a6ed44e0813084efecfd9afdcb90e.tar.bz2 linux-f3f0a9d17f2a6ed44e0813084efecfd9afdcb90e.zip | |
libceph: avoid KEEPALIVE_PENDING races in ceph_con_keepalive()
commit 4aac9228d16458cedcfd90c7fb37211cf3653ac3 upstream.
con_fault() can transition the connection into STANDBY right after
ceph_con_keepalive() clears STANDBY in clear_standby():
libceph user thread ceph-msgr worker
ceph_con_keepalive()
mutex_lock(&con->mutex)
clear_standby(con)
mutex_unlock(&con->mutex)
mutex_lock(&con->mutex)
con_fault()
...
if KEEPALIVE_PENDING isn't set
set state to STANDBY
...
mutex_unlock(&con->mutex)
set KEEPALIVE_PENDING
set WRITE_PENDING
This triggers warnings in clear_standby() when either ceph_con_send()
or ceph_con_keepalive() get to clearing STANDBY next time.
I don't see a reason to condition queue_con() call on the previous
value of KEEPALIVE_PENDING, so move the setting of KEEPALIVE_PENDING
into the critical section -- unlike WRITE_PENDING, KEEPALIVE_PENDING
could have been a non-atomic flag.
Reported-by: syzbot+acdeb633f6211ccdf886@syzkaller.appspotmail.com
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Tested-by: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ceph/messenger.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 5a8075d9f2e7..93eb606f7628 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -3186,9 +3186,10 @@ void ceph_con_keepalive(struct ceph_connection *con) dout("con_keepalive %p\n", con); mutex_lock(&con->mutex); clear_standby(con); + con_flag_set(con, CON_FLAG_KEEPALIVE_PENDING); mutex_unlock(&con->mutex); - if (con_flag_test_and_set(con, CON_FLAG_KEEPALIVE_PENDING) == 0 && - con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0) + + if (con_flag_test_and_set(con, CON_FLAG_WRITE_PENDING) == 0) queue_con(con); } EXPORT_SYMBOL(ceph_con_keepalive); |