2ef7665dfd
Target de-configuration panics at high CPU load because TPGT and WWPN can be removed on separate threads. TPGT removal requests a reset HBA on a separate thread and waits for reset complete (phase1). Due to high CPU load that HBA reset can be delayed for some time. WWPN removal does qlt_stop_phase2(). There it is believed that phase1 has already completed and thus tgt.tgt_ops is subsequently cleared. However, tgt.tgt_ops is needed to process incoming traffic and therefore this will cause one of the following panics: NIP qlt_reset+0x7c/0x220 [qla2xxx] LR qlt_reset+0x68/0x220 [qla2xxx] Call Trace: 0xc000003ffff63a78 (unreliable) qlt_handle_imm_notify+0x800/0x10c0 [qla2xxx] qlt_24xx_atio_pkt+0x208/0x590 [qla2xxx] qlt_24xx_process_atio_queue+0x33c/0x7a0 [qla2xxx] qla83xx_msix_atio_q+0x54/0x90 [qla2xxx] or NIP qlt_24xx_handle_abts+0xd0/0x2a0 [qla2xxx] LR qlt_24xx_handle_abts+0xb4/0x2a0 [qla2xxx] Call Trace: qlt_24xx_handle_abts+0x90/0x2a0 [qla2xxx] (unreliable) qlt_24xx_process_atio_queue+0x500/0x7a0 [qla2xxx] qla83xx_msix_atio_q+0x54/0x90 [qla2xxx] or NIP qlt_create_sess+0x90/0x4e0 [qla2xxx] LR qla24xx_do_nack_work+0xa8/0x180 [qla2xxx] Call Trace: 0xc0000000348fba30 (unreliable) qla24xx_do_nack_work+0xa8/0x180 [qla2xxx] qla2x00_do_work+0x674/0xbf0 [qla2xxx] qla2x00_iocb_work_fn The patch fixes the issue by serializing qlt_stop_phase1() and qlt_stop_phase2() functions to make WWPN removal wait for phase1 completion. Link: https://lore.kernel.org/r/20210415203554.27890-1-d.bogdanov@yadro.com Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com> Signed-off-by: Dmitry Bogdanov <d.bogdanov@yadro.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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.