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Dmitry Bogdanov
dd0a66ada0
Under huge load there is a possibility of race condition in updating se_dev_entry object in ACL removal procedure: NIP [c0080000154093d0] transport_lookup_cmd_lun+0x1f8/0x3d0 [target_core_mod] LR [c00800001542ab34] target_submit_cmd_map_sgls+0x11c/0x300 [target_core_mod] Call Trace: target_submit_cmd_map_sgls+0x11c/0x300 [target_core_mod] target_submit_cmd+0x44/0x60 [target_core_mod] tcm_qla2xxx_handle_cmd+0x88/0xe0 [tcm_qla2xxx] qlt_do_work+0x2e4/0x3d0 [qla2xxx] process_one_work+0x298/0x5c Despite usage of RCU primitives with deve->se_lun pointer, it has not become dereference-safe because deve->se_lun is updated and not synchronized with a reader. That change might be in a release function called by synchronize_rcu(). But, in fact, there is no point in setting that pointer to NULL for deleting deve. All access to deve->se_lun is already under rcu_read_lock. And either deve->se_lun is always valid or deve is not valid itself and will not be found in the list_for_*. The same applicable for deve->se_lun_acl too. So a better solution is to remove that NULLing. Link: https://lore.kernel.org/r/20220727214125.19647-2-d.bogdanov@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>
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.