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[ Upstream commit12b6fcd0ea] 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:c66ac9db8d("[SCSI] target: Add LIO target core v4.0.0-rc6") Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com> Reviewed-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.