If a request is put on the waiting list, its submission is postponed until the session becomes ready (e.g. via `mdsc->waiting_for_map` or `session->s_waiting`). If a `CEPH_MSG_CLIENT_REPLY` happens to be received before `CEPH_MSG_MDS_MAP`, the request gets freed, and then this assertion fails: WARN_ON_ONCE(!list_empty(&req->r_wait)); This occurred on a server after the Ceph MDS connection failed, and a corrupt reply packet was received for a waiting request: libceph: mds1 (1)10.0.0.10:6801 socket error on write libceph: mds1 (1)10.0.0.10:6801 session reset ceph: mds1 closed our session ceph: mds1 reconnect start ceph: mds1 reconnect success ceph: problem parsing mds trace -5 ceph: mds parse_reply err -5 ceph: mdsc_handle_reply got corrupt reply mds1(tid:5530222) [...] ------------[ cut here ]------------ WARNING: CPU: 9 PID: 229180 at fs/ceph/mds_client.c:966 ceph_mdsc_release_request+0x17a/0x180 Modules linked in: CPU: 9 PID: 229180 Comm: kworker/9:3 Not tainted 6.1.8-cm4all1 #45 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Workqueue: ceph-msgr ceph_con_workfn RIP: 0010:ceph_mdsc_release_request+0x17a/0x180 Code: 39 d8 75 26 5b 48 89 ee 48 8b 3d f9 2d 04 02 5d e9 fb 01 c9 ff e8 56 85 ab ff eb 9c 48 8b 7f 58 e8 db 4d ff ff e9 a4 fe ff ff <0f> 0b eb d6 66 90 0f 1f 44 00 00 41 54 48 8d 86 b8 03 00 00 55 4c RSP: 0018:ffffa6f2c0e2bd20 EFLAGS: 00010287 RAX: ffff8f58b93687f8 RBX: ffff8f592f6374a8 RCX: 0000000000000aed RDX: 0000000000000ac0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff8f592f637148 R08: 0000000000000001 R09: ffffffffa901de00 R10: 0000000000000001 R11: ffffd630ad09dfc8 R12: ffff8f58b9368000 R13: ffff8f5806b33800 R14: ffff8f58894f6780 R15: 000000000054626e FS: 0000000000000000(0000) GS:ffff8f630f040000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc2926df68 CR3: 0000000218dce002 CR4: 00000000001706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> mds_dispatch+0xec5/0x1460 ? inet_recvmsg+0x4d/0xf0 ceph_con_process_message+0x6b/0x80 ceph_con_v1_try_read+0xb92/0x1400 ceph_con_workfn+0x383/0x4e0 process_one_work+0x1da/0x370 ? process_one_work+0x370/0x370 worker_thread+0x4d/0x3c0 ? process_one_work+0x370/0x370 kthread+0xbb/0xe0 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK> ---[ end trace 0000000000000000 ]--- ceph: mds1 caps renewed If we know that a request has not yet been submitted, we should ignore all responses for it, just like we ignore responses for unknown TIDs. To: ceph-devel@xxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx> --- fs/ceph/mds_client.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 27a245d959c0..fa74fdb2cbfb 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -3275,6 +3275,13 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg) } dout("handle_reply %p\n", req); + /* waiting, not yet submitted? */ + if (!list_empty(&req->r_wait)) { + pr_err("mdsc_handle_reply on waiting request tid %llu\n", tid); + mutex_unlock(&mdsc->mutex); + goto out; + } + /* correct session? */ if (req->r_session != session) { pr_err("mdsc_handle_reply got %llu on session mds%d" -- 2.39.2