kernel/git/stable/linux.git/drivers/s390, branch linux-5.2.y

virtio/s390: fix race on airq_areas[]

2019-09-16T06:23:22+00:00

[ Upstream commit 4f419eb14272e0698e8c55bb5f3f266cc2a21c81 ] The access to airq_areas was racy ever since the adapter interrupts got introduced to virtio-ccw, but since commit 39c7dcb15892 ("virtio/s390: make airq summary indicators DMA") this became an issue in practice as well. Namely before that commit the airq_info that got overwritten was still functional. After that commit however the two infos share a summary_indicator, which aggravates the situation. Which means auto-online mechanism occasionally hangs the boot with virtio_blk. Signed-off-by: Halil Pasic Reported-by: Marc Hartmayer Reviewed-by: Cornelia Huck Cc: stable@vger.kernel.org Fixes: 96b14536d935 ("virtio-ccw: virtio-ccw adapter interrupt support.") Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/qeth: serialize cmd reply with concurrent timeout

2019-09-10T09:35:14+00:00

[ Upstream commit 072f79400032f74917726cf76f4248367ea2b5b8 ] Callbacks for a cmd reply run outside the protection of card->lock, to allow for additional cmds to be issued & enqueued in parallel. When qeth_send_control_data() bails out for a cmd without having received a reply (eg. due to timeout), its callback may concurrently be processing a reply that just arrived. In this case, the callback potentially accesses a stale reply->reply_param area that eg. was on-stack and has already been released. To avoid this race, add some locking so that qeth_send_control_data() can (1) wait for a concurrently running callback, and (2) zap any pending callback that still wants to run. Signed-off-by: Julian Wiedmann Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

s390/qdio: add sanity checks to the fast-requeue path

2019-08-16T08:11:04+00:00

[ Upstream commit a6ec414a4dd529eeac5c3ea51c661daba3397108 ] If the device driver were to send out a full queue's worth of SBALs, current code would end up discovering the last of those SBALs as PRIMED and erroneously skip the SIGA-w. This immediately stalls the queue. Add a check to not attempt fast-requeue in this case. While at it also make sure that the state of the previous SBAL was successfully extracted before inspecting it. Signed-off-by: Julian Wiedmann Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

vfio-ccw: Don't call cp_free if we are processing a channel program

2019-08-16T08:10:58+00:00

[ Upstream commit f4c9939433bd396d0b08e803b2b880a9d02682b9 ] There is a small window where it's possible that we could be working on an interrupt (queued in the workqueue) and setting up a channel program (i.e allocating memory, pinning pages, translating address). This can lead to allocating and freeing the channel program at the same time and can cause memory corruption. Let's not call cp_free if we are currently processing a channel program. The only way we know for sure that we don't have a thread setting up a channel program is when the state is set to VFIO_CCW_STATE_CP_PENDING. Fixes: d5afd5d135c8 ("vfio-ccw: add handling for async channel instructions") Signed-off-by: Farhan Ali Reviewed-by: Cornelia Huck Message-Id: <62e87bf67b38dc8d5760586e7c96d400db854ebe.1562854091.git.alifm@linux.ibm.com> Reviewed-by: Eric Farman Signed-off-by: Cornelia Huck Signed-off-by: Sasha Levin

vfio-ccw: Set pa_nr to 0 if memory allocation fails for pa_iova_pfn

2019-08-16T08:10:58+00:00

[ Upstream commit c1ab69268d124ebdbb3864580808188ccd3ea355 ] So we don't call try to call vfio_unpin_pages() incorrectly. Fixes: 0a19e61e6d4c ("vfio: ccw: introduce channel program interfaces") Signed-off-by: Farhan Ali Reviewed-by: Eric Farman Reviewed-by: Cornelia Huck Message-Id: <33a89467ad6369196ae6edf820cbcb1e2d8d050c.1562854091.git.alifm@linux.ibm.com> Signed-off-by: Cornelia Huck Signed-off-by: Sasha Levin

s390/dasd: fix endless loop after read unit address configuration

2019-08-06T17:08:18+00:00

commit 41995342b40c418a47603e1321256d2c4a2ed0fb upstream. After getting a storage server event that causes the DASD device driver to update its unit address configuration during a device shutdown there is the possibility of an endless loop in the device driver. In the system log there will be ongoing DASD error messages with RC: -19. The reason is that the loop starting the ruac request only terminates when the retry counter is decreased to 0. But in the sleep_on function there are early exit paths that do not decrease the retry counter. Prevent an endless loop by handling those cases separately. Remove the unnecessary do..while loop since the sleep_on function takes care of retries by itself. Fixes: 8e09f21574ea ("[S390] dasd: add hyper PAV support to DASD device driver, part 1") Cc: stable@vger.kernel.org # 2.6.25+ Signed-off-by: Stefan Haberland Reviewed-by: Jan Hoeppner Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

scsi: zfcp: fix GCC compiler warning emitted with -Wmaybe-uninitialized

2019-08-06T17:08:08+00:00

[ Upstream commit 484647088826f2f651acbda6bcf9536b8a466703 ] GCC v9 emits this warning: CC drivers/s390/scsi/zfcp_erp.o drivers/s390/scsi/zfcp_erp.c: In function 'zfcp_erp_action_enqueue': drivers/s390/scsi/zfcp_erp.c:217:26: warning: 'erp_action' may be used uninitialized in this function [-Wmaybe-uninitialized] 217 | struct zfcp_erp_action *erp_action; | ^~~~~~~~~~ This is a possible false positive case, as also documented in the GCC documentations: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wmaybe-uninitialized The actual code-sequence is like this: Various callers can invoke the function below with the argument "want" being one of: ZFCP_ERP_ACTION_REOPEN_ADAPTER, ZFCP_ERP_ACTION_REOPEN_PORT_FORCED, ZFCP_ERP_ACTION_REOPEN_PORT, or ZFCP_ERP_ACTION_REOPEN_LUN. zfcp_erp_action_enqueue(want, ...) ... need = zfcp_erp_required_act(want, ...) need = want ... maybe: need = ZFCP_ERP_ACTION_REOPEN_PORT maybe: need = ZFCP_ERP_ACTION_REOPEN_ADAPTER ... return need ... zfcp_erp_setup_act(need, ...) struct zfcp_erp_action *erp_action; // <== line 217 ... switch(need) { case ZFCP_ERP_ACTION_REOPEN_LUN: ... erp_action = &zfcp_sdev->erp_action; WARN_ON_ONCE(erp_action->port != port); // <== access ... break; case ZFCP_ERP_ACTION_REOPEN_PORT: case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED: ... erp_action = &port->erp_action; WARN_ON_ONCE(erp_action->port != port); // <== access ... break; case ZFCP_ERP_ACTION_REOPEN_ADAPTER: ... erp_action = &adapter->erp_action; WARN_ON_ONCE(erp_action->port != NULL); // <== access ... break; } ... WARN_ON_ONCE(erp_action->adapter != adapter); // <== access When zfcp_erp_setup_act() is called, 'need' will never be anything else than one of the 4 possible enumeration-names that are used in the switch-case, and 'erp_action' is initialized for every one of them, before it is used. Thus the warning is a false positive, as documented. We introduce the extra if{} in the beginning to create an extra code-flow, so the compiler can be convinced that the switch-case will never see any other value. BUG_ON()/BUG() is intentionally not used to not crash anything, should this ever happen anyway - right now it's impossible, as argued above; and it doesn't introduce a 'default:' switch-case to retain warnings should 'enum zfcp_erp_act_type' ever be extended and no explicit case be introduced. See also v5.0 commit 399b6c8bc9f7 ("scsi: zfcp: drop old default switch case which might paper over missing case"). Signed-off-by: Benjamin Block Reviewed-by: Jens Remus Reviewed-by: Steffen Maier Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

scsi: zfcp: fix request object use-after-free in send path causing wrong traces

2019-07-26T07:10:49+00:00

commit 106d45f350c7cac876844dc685845cba4ffdb70b upstream. When tracing instances where we open and close WKA ports, we also pass the request-ID of the respective FSF command. But after successfully sending the FSF command we must not use the request-object anymore, as this might result in an use-after-free (see "zfcp: fix request object use-after-free in send path causing seqno errors" ). To fix this add a new variable that caches the request-ID before sending the request. This won't change during the hand-off to the FCP channel, and so it's safe to trace this cached request-ID later, instead of using the request object. Signed-off-by: Benjamin Block Fixes: d27a7cb91960 ("zfcp: trace on request for open and close of WKA port") Cc: #2.6.38+ Reviewed-by: Steffen Maier Reviewed-by: Jens Remus Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

scsi: zfcp: fix request object use-after-free in send path causing seqno errors

2019-07-26T07:10:48+00:00

commit b76becde2b84137faa29bbc9a3b20953b5980e48 upstream. With a recent change to our send path for FSF commands we introduced a possible use-after-free of request-objects, that might further lead to zfcp crafting bad requests, which the FCP channel correctly complains about with an error (FSF_PROT_SEQ_NUMB_ERROR). This error is then handled by an adapter-wide recovery. The following sequence illustrates the possible use-after-free: Send Path: int zfcp_fsf_open_port(struct zfcp_erp_action *erp_action) { struct zfcp_fsf_req *req; ... spin_lock_irq(&qdio->req_q_lock); // ^^^^^^^^^^^^^^^^ // protects QDIO queue during sending ... req = zfcp_fsf_req_create(qdio, FSF_QTCB_OPEN_PORT_WITH_DID, SBAL_SFLAGS0_TYPE_READ, qdio->adapter->pool.erp_req); // ^^^^^^^^^^^^^^^^^^^ // allocation of the request-object ... retval = zfcp_fsf_req_send(req); ... spin_unlock_irq(&qdio->req_q_lock); return retval; } static int zfcp_fsf_req_send(struct zfcp_fsf_req *req) { struct zfcp_adapter *adapter = req->adapter; struct zfcp_qdio *qdio = adapter->qdio; ... zfcp_reqlist_add(adapter->req_list, req); // ^^^^^^^^^^^^^^^^ // add request to our driver-internal hash-table for tracking // (protected by separate lock req_list->lock) ... if (zfcp_qdio_send(qdio, &req->qdio_req)) { // ^^^^^^^^^^^^^^ // hand-off the request to FCP channel; // the request can complete at any point now ... } /* Don't increase for unsolicited status */ if (!zfcp_fsf_req_is_status_read_buffer(req)) // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ // possible use-after-free adapter->fsf_req_seq_no++; // ^^^^^^^^^^^^^^^^ // because of the use-after-free we might // miss this accounting, and as follow-up // this results in the FCP channel error // FSF_PROT_SEQ_NUMB_ERROR adapter->req_no++; return 0; } static inline bool zfcp_fsf_req_is_status_read_buffer(struct zfcp_fsf_req *req) { return req->qtcb == NULL; // ^^^^^^^^^ // possible use-after-free } Response Path: void zfcp_fsf_reqid_check(struct zfcp_qdio *qdio, int sbal_idx) { ... struct zfcp_fsf_req *fsf_req; ... for (idx = 0; idx < QDIO_MAX_ELEMENTS_PER_BUFFER; idx++) { ... fsf_req = zfcp_reqlist_find_rm(adapter->req_list, req_id); // ^^^^^^^^^^^^^^^^^^^^ // remove request from our driver-internal // hash-table (lock req_list->lock) ... zfcp_fsf_req_complete(fsf_req); } } static void zfcp_fsf_req_complete(struct zfcp_fsf_req *req) { ... if (likely(req->status & ZFCP_STATUS_FSFREQ_CLEANUP)) zfcp_fsf_req_free(req); // ^^^^^^^^^^^^^^^^^ // free memory for request-object else complete(&req->completion); // ^^^^^^^^ // completion notification for code-paths that wait // synchronous for the completion of the request; in // those the memory is freed separately } The result of the use-after-free only affects the send path, and can not lead to any data corruption. In case we miss the sequence-number accounting, because the memory was already re-purposed, the next FSF command will fail with said FCP channel error, and we will recover the whole adapter. This causes no additional errors, but it slows down traffic. There is a slight chance of the same thing happen again recursively after the adapter recovery, but so far this has not been seen. This was seen under z/VM, where the send path might run on a virtual CPU that gets scheduled away by z/VM, while the return path might still run, and so create the necessary timing. Running with KASAN can also slow down the kernel sufficiently to run into this user-after-free, and then see the report by KASAN. To fix this, simply pull the test for the sequence-number accounting in front of the hand-off to the FCP channel (this information doesn't change during hand-off), but leave the sequence-number accounting itself where it is. To make future regressions of the same kind less likely, add comments to all closely related code-paths. Signed-off-by: Benjamin Block Fixes: f9eca0227600 ("scsi: zfcp: drop duplicate fsf_command from zfcp_fsf_req which is also in QTCB header") Cc: #5.0+ Reviewed-by: Steffen Maier Reviewed-by: Jens Remus Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

s390/qdio: handle PENDING state for QEBSM devices

2019-07-26T07:10:23+00:00

[ Upstream commit 04310324c6f482921c071444833e70fe861b73d9 ] When a CQ-enabled device uses QEBSM for SBAL state inspection, get_buf_states() can return the PENDING state for an Output Queue. get_outbound_buffer_frontier() isn't prepared for this, and any PENDING buffer will permanently stall all further completion processing on this Queue. This isn't a concern for non-QEBSM devices, as get_buf_states() for such devices will manually turn PENDING buffers into EMPTY ones. Fixes: 104ea556ee7f ("qdio: support asynchronous delivery of storage blocks") Signed-off-by: Julian Wiedmann Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin