pm24.git/drivers/target/target_core_tmr.c, branch v6.8

scsi: target: Fix multiple LUN_RESET handling

2023-03-24T21:32:23Z

This fixes a bug where an initiator thinks a LUN_RESET has cleaned up running commands when it hasn't. The bug was added in commit 51ec502a3266 ("target: Delete tmr from list before processing"). The problem occurs when: 1. We have N I/O cmds running in the target layer spread over 2 sessions. 2. The initiator sends a LUN_RESET for each session. 3. session1's LUN_RESET loops over all the running commands from both sessions and moves them to its local drain_task_list. 4. session2's LUN_RESET does not see the LUN_RESET from session1 because the commit above has it remove itself. session2 also does not see any commands since the other reset moved them off the state lists. 5. sessions2's LUN_RESET will then complete with a successful response. 6. sessions2's inititor believes the running commands on its session are now cleaned up due to the successful response and cleans up the running commands from its side. It then restarts them. 7. The commands do eventually complete on the backend and the target starts to return aborted task statuses for them. The initiator will either throw a invalid ITT error or might accidentally lookup a new task if the ITT has been reallocated already. Fix the bug by reverting the patch, and serialize the execution of LUN_RESETs and Preempt and Aborts. Also prevent us from waiting on LUN_RESETs in core_tmr_drain_tmr_list, because it turns out the original patch fixed a bug that was not mentioned. For LUN_RESET1 core_tmr_drain_tmr_list can see a second LUN_RESET and wait on it. Then the second reset will run core_tmr_drain_tmr_list and see the first reset and wait on it resulting in a deadlock. Fixes: 51ec502a3266 ("target: Delete tmr from list before processing") Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/20230319015620.96006-8-michael.christie@oracle.com Signed-off-by: Martin K. Petersen

scsi: target: core: Fix warning on RT kernels

2023-01-14T01:24:24Z

Calling spin_lock_irqsave() does not disable the interrupts on realtime kernels, remove the warning and replace assert_spin_locked() with lockdep_assert_held(). Signed-off-by: Maurizio Lombardi Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20230110125310.55884-1-mlombard@redhat.com Signed-off-by: Martin K. Petersen

scsi: target: core: Remove from tmr_list during LUN unlink

2021-10-27T03:15:23Z

Currently TMF commands are removed from de_device.dev_tmf_list at the very end of se_cmd lifecycle. However, se_lun unlinks from se_cmd upon a command status (response) being queued in transport layer. This means that LUN and backend device can be deleted in the meantime and a panic will occur: target_tmr_work() cmd->se_tfo->queue_tm_rsp(cmd); // send abort_rsp to a wire transport_lun_remove_cmd(cmd) // unlink se_cmd from se_lun - // - // - // - <<<--- lun remove <<<--- core backend device remove - // - // - // - qlt_handle_abts_completion() tfo->free_mcmd() transport_generic_free_cmd() target_put_sess_cmd() core_tmr_release_req() { if (dev) { // backend device, can not be null spin_lock_irqsave(&dev->se_tmr_lock, flags); //<<<--- CRASH Call Trace: NIP [c000000000e1683c] _raw_spin_lock_irqsave+0x2c/0xc0 LR [c00800000e433338] core_tmr_release_req+0x40/0xa0 [target_core_mod] Call Trace: (unreliable) 0x0 target_put_sess_cmd+0x2a0/0x370 [target_core_mod] transport_generic_free_cmd+0x6c/0x1b0 [target_core_mod] tcm_qla2xxx_complete_mcmd+0x28/0x50 [tcm_qla2xxx] process_one_work+0x2c4/0x5c0 worker_thread+0x88/0x690 For the iSCSI protocol this is easily reproduced: - Send some SCSI sommand - Send Abort of that command over iSCSI - Remove LUN on target - Send next iSCSI command to acknowledge the Abort_Response - Target panics There is no need to keep the command in tmr_list until response completion, so move the removal from tmr_list from the response completion to the response queueing when the LUN is unlinked. Move the removal from state list too as it is a subject to the same race condition. Link: https://lore.kernel.org/r/20211018135753.15297-1-d.bogdanov@yadro.com Fixes: c66ac9db8d4a ("[SCSI] target: Add LIO target core v4.0.0-rc6") Reviewed-by: Roman Bolshakov Reviewed-by: Mike Christie Signed-off-by: Dmitry Bogdanov Signed-off-by: Martin K. Petersen

scsi: target: core: Flush submission work during TMR processing

2021-03-04T22:37:02Z

If a cmd is on the submission workqueue then the TMR code will miss it, and end up returning task not found or success for LUN resets. The fabric driver might then tell the initiator that the running cmds have been handled when they are about to run. This adds a flush when we are processing TMRs to make sure queued cmds do not run after returning the TMR response. Link: https://lore.kernel.org/r/20210227170006.5077-25-michael.christie@oracle.com Tested-by: Laurence Oberman Reviewed-by: Bodo Stroesser Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen

scsi: target: Make state_list per CPU

2020-11-05T03:39:38Z

Do a state_list/execute_task_lock per CPU, so we can do submissions from different CPUs without contention with each other. Note: tcm_fc was passing TARGET_SCF_USE_CPUID, but never set cpuid. The assumption is that it wanted to set the cpuid to the CPU it was submitting from so it will get this behavior with this patch. [mkp: s/printk/pr_err/ + resolve COMPARE AND WRITE patch conflict] Link: https://lore.kernel.org/r/1604257174-4524-8-git-send-email-michael.christie@oracle.com Reviewed-by: Himanshu Madhani Signed-off-by: Mike Christie Signed-off-by: Martin K. Petersen

scsi: target: Add tmr_notify backend function

2020-07-29T02:25:26Z

Target core is modified to call an optional backend callback function if a TMR is received or commands are aborted implicitly after a PR command was received. The backend function takes as parameters the se_dev, the type of the TMR, and the list of aborted commands. If no commands were aborted, an empty list is supplied. Link: https://lore.kernel.org/r/20200726153510.13077-3-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen

scsi: target: Modify core_tmr_abort_task()

2020-07-29T02:25:25Z

This patch modifies core_tmr_abort_task() to use same looping and locking scheme as core_tmr_drain_state_list() does. This frees the state_list element in se_cmd for later use by tmr notification handling. Note: __target_check_io_state() now is called with param 0 instead of dev->dev_attrib.emulate_tas, because tas is not relevant since we always get ABRT on same session like the aborted command. Link: https://lore.kernel.org/r/20200726153510.13077-2-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen

scsi: target: Initialize LUN in transport_init_se_cmd()

2020-06-10T01:57:26Z

Initialization of orig_fe_lun is moved to transport_init_se_cmd() from transport_lookup_cmd_lun(). This helps for the cases where the SCSI request fails before the call to transport_lookup_cmd_lun() so that trace_target_cmd_complete() can print the LUN information to the trace buffer. Due to this change, the lun parameter is removed from transport_lookup_cmd_lun() and transport_lookup_tmr_lun(). Link: https://lore.kernel.org/r/1591559913-8388-3-git-send-email-sudhakar.panneerselvam@oracle.com Reviewed-by: Mike Christie Signed-off-by: Sudhakar Panneerselvam Signed-off-by: Martin K. Petersen

scsi: target: convert boolean se_dev_attrib types to bool

2020-02-21T22:37:14Z

This should harden us against configfs API regressions similar to the one fixed by the previous commit. Link: https://marc.info/?l=target-devel&m=158211731505174 Signed-off-by: David Disseldorp Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman