kernel/linux.git/drivers/s390, branch v4.19.16

scsi: zfcp: fix posting too many status read buffers leading to adapter shutdown

2019-01-13T08:51:03+00:00

commit 60a161b7e5b2a252ff0d4c622266a7d8da1120ce upstream. Suppose adapter (open) recovery is between opened QDIO queues and before (the end of) initial posting of status read buffers (SRBs). This time window can be seconds long due to FSF_PROT_HOST_CONNECTION_INITIALIZING causing by design looping with exponential increase sleeps in the function performing exchange config data during recovery [zfcp_erp_adapter_strat_fsf_xconf()]. Recovery triggered by local link up. Suppose an event occurs for which the FCP channel would send an unsolicited notification to zfcp by means of a previously posted SRB. We saw it with local cable pull (link down) in multi-initiator zoning with multiple NPIV-enabled subchannels of the same shared FCP channel. As soon as zfcp_erp_adapter_strategy_open_fsf() starts posting the initial status read buffers from within the adapter's ERP thread, the channel does send an unsolicited notification. Since v2.6.27 commit d26ab06ede83 ("[SCSI] zfcp: receiving an unsolicted status can lead to I/O stall"), zfcp_fsf_status_read_handler() schedules adapter->stat_work to re-fill the just consumed SRB from a work item. Now the ERP thread and the work item post SRBs in parallel. Both contexts call the helper function zfcp_status_read_refill(). The tracking of missing (to be posted / re-filled) SRBs is not thread-safe due to separate atomic_read() and atomic_dec(), in order to depend on posting success. Hence, both contexts can see atomic_read(&adapter->stat_miss) == 1. One of the two contexts posts one too many SRB. Zfcp gets QDIO_ERROR_SLSB_STATE on the output queue (trace tag "qdireq1") leading to zfcp_erp_adapter_shutdown() in zfcp_qdio_handler_error(). An obvious and seemingly clean fix would be to schedule stat_work from the ERP thread and wait for it to finish. This would serialize all SRB re-fills. However, we already have another work item wait on the ERP thread: adapter->scan_work runs zfcp_fc_scan_ports() which calls zfcp_fc_eval_gpn_ft(). The latter calls zfcp_erp_wait() to wait for all the open port recoveries during zfcp auto port scan, but in fact it waits for any pending recovery including an adapter recovery. This approach leads to a deadlock. [see also v3.19 commit 18f87a67e6d6 ("zfcp: auto port scan resiliency"); v2.6.37 commit d3e1088d6873 ("[SCSI] zfcp: No ERP escalation on gpn_ft eval"); v2.6.28 commit fca55b6fb587 ("[SCSI] zfcp: fix deadlock between wq triggered port scan and ERP") fixing v2.6.27 commit c57a39a45a76 ("[SCSI] zfcp: wait until adapter is finished with ERP during auto-port"); v2.6.27 commit cc8c282963bd ("[SCSI] zfcp: Automatically attach remote ports")] Instead make the accounting of missing SRBs atomic for parallel execution in both the ERP thread and adapter->stat_work. Signed-off-by: Steffen Maier Fixes: d26ab06ede83 ("[SCSI] zfcp: receiving an unsolicted status can lead to I/O stall") Cc: #2.6.27+ Reviewed-by: Jens Remus Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

s390/cio: Fix cleanup when unsupported IDA format is used

2018-12-17T08:24:31+00:00

[ Upstream commit b89e242eee8d4cd8261d8d821c62c5d1efc454d0 ] Direct returns from within a loop are rude, but it doesn't mean it gets to avoid releasing the memory acquired beforehand. Signed-off-by: Eric Farman Message-Id: <20181109023937.96105-3-farman@linux.ibm.com> Reviewed-by: Farhan Ali Reviewed-by: Pierre Morel Acked-by: Halil Pasic Signed-off-by: Cornelia Huck Signed-off-by: Sasha Levin

s390/cio: Fix cleanup of pfn_array alloc failure

2018-12-17T08:24:31+00:00

[ Upstream commit 806212f91c874b24cf9eb4a9f180323671b6c5ed ] If pfn_array_alloc fails somehow, we need to release the pfn_array_table that was malloc'd earlier. Signed-off-by: Eric Farman Message-Id: <20181109023937.96105-2-farman@linux.ibm.com> Acked-by: Halil Pasic Signed-off-by: Cornelia Huck Signed-off-by: Sasha Levin

virtio/s390: fix race in ccw_io_helper()

2018-12-13T08:16:18+00:00

commit 78b1a52e05c9db11d293342e8d6d8a230a04b4e7 upstream. While ccw_io_helper() seems like intended to be exclusive in a sense that it is supposed to facilitate I/O for at most one thread at any given time, there is actually nothing ensuring that threads won't pile up at vcdev->wait_q. If they do, all threads get woken up and see the status that belongs to some other request than their own. This can lead to bugs. For an example see: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1788432 This race normally does not cause any problems. The operations provided by struct virtio_config_ops are usually invoked in a well defined sequence, normally don't fail, and are normally used quite infrequent too. Yet, if some of the these operations are directly triggered via sysfs attributes, like in the case described by the referenced bug, userspace is given an opportunity to force races by increasing the frequency of the given operations. Let us fix the problem by ensuring, that for each device, we finish processing the previous request before starting with a new one. Signed-off-by: Halil Pasic Reported-by: Colin Ian King Cc: stable@vger.kernel.org Message-Id: <20180925121309.58524-3-pasic@linux.ibm.com> Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio/s390: avoid race on vcdev->config

2018-12-13T08:16:18+00:00

commit 2448a299ec416a80f699940a86f4a6d9a4f643b1 upstream. Currently we have a race on vcdev->config in virtio_ccw_get_config() and in virtio_ccw_set_config(). This normally does not cause problems, as these are usually infrequent operations. However, for some devices writing to/reading from the config space can be triggered through sysfs attributes. For these, userspace can force the race by increasing the frequency. Signed-off-by: Halil Pasic Cc: stable@vger.kernel.org Message-Id: <20180925121309.58524-2-pasic@linux.ibm.com> Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

s390/ism: clear dmbe_mask bit before SMC IRQ handling

2018-12-13T08:16:11+00:00

[ Upstream commit 007b656851ed7f94ba0fa358ac3e5d7705da6846 ] SMC-D stress workload showed connection stalls. Since the firmware decides to skip raising an interrupt if the SBA DMBE mask bit is still set, this SBA DMBE mask bit should be cleared before the IRQ handling in the SMC code runs. Otherwise there are small windows possible with missing interrupts for incoming data. SMC-D currently does not care about the old value of the SBA DMBE mask. Acked-by: Sebastian Ott Signed-off-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

s390/qeth: fix length check in SNMP processing

2018-12-05T18:31:59+00:00

[ Upstream commit 9a764c1e59684c0358e16ccaafd870629f2cfe67 ] The response for a SNMP request can consist of multiple parts, which the cmd callback stages into a kernel buffer until all parts have been received. If the callback detects that the staging buffer provides insufficient space, it bails out with error. This processing is buggy for the first part of the response - while it initially checks for a length of 'data_len', it later copies an additional amount of 'offsetof(struct qeth_snmp_cmd, data)' bytes. Fix the calculation of 'data_len' for the first part of the response. This also nicely cleans up the memcpy code. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Julian Wiedmann Reviewed-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

s390/qeth: unregister netdevice only when registered

2018-11-27T15:13:03+00:00

[ Upstream commit 30356d08159d7899438e94503ae322a8b881e205 ] qeth only registers its netdevice when the qeth device is first set online. Thus a device that has never been set online will trigger a WARN ("network todo 'hsi%d' but state 0") in unregister_netdev() when removed. Fix this by protecting the unregister step, just like we already protect against repeated registering of the netdevice. Fixes: d3d1b205e89f ("s390/qeth: allocate netdevice early") Reported-by: Karsten Graul Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

s390/qeth: fix HiperSockets sniffer

2018-11-27T15:13:03+00:00

[ Upstream commit bd74a7f9cc033cf4d405788f80292268987dc0c5 ] Sniffing mode for L3 HiperSockets requires that no IP addresses are registered with the HW. The preferred way to achieve this is for userspace to delete all the IPs on the interface. But qeth is expected to also tolerate a configuration where that is not the case, by skipping the IP registration when in sniffer mode. Since commit 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback") reworked the IP registration logic in the L3 subdriver, this no longer works. When the qeth device is set online, qeth_l3_recover_ip() now unconditionally registers all unicast addresses from our internal IP table. While we could fix this particular problem by skipping qeth_l3_recover_ip() on a sniffer device, the more future-proof change is to skip the IP address registration at the lowest level. This way we a) catch any future code path that attempts to register an IP address without considering the sniffer scenario, and b) continue to build up our internal IP table, so that if sniffer mode is switched off later we can operate just like normal. Fixes: 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

Merge tag 's390-4.19-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2018-10-10T06:44:35+00:00

Martin writes: "s390 fixes for 4.19-rc8 Four more patches for 4.19: - Fix resume after suspend-to-disk if resume-CPU != suspend-CPU - Fix vfio-ccw check for pinned pages - Two patches to avoid a usercopy-whitelist warning in vfio-ccw" * tag 's390-4.19-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/cio: Fix how vfio-ccw checks pinned pages s390/cio: Refactor alloc of ccw_io_region s390/cio: Convert ccw_io_region to pointer s390/hibernate: fix error handling when suspend cpu != resume cpu