Gleb Chesnokov
2d7183ce83
When every valid fallback tag is occupied, find_first_zero_bit returns tag_num. The old loop calls test_and_set_bit before checking that sentinel. If the bit was clear, it even exits the loop without checking the range and uses tag_num as an index into tgt_cmd_map. For word-aligned pool sizes this touches a word beyond the bitmap. For other sizes it can claim padding in the last word. Both cases can return an out-of-range command-map entry and let memset overwrite memory beyond the map. Manual review found this bounds bug while auditing the fallback allocation flagged by Coccinelle null/kmerr.cocci. No separate analyzer diagnostic reported the invalid bitmap or command-map access. Check the sentinel before test_and_set_bit and return -ENOENT when no tag is available. Preserve the retry when another allocator wins the bit. Expose the helper to the QLA KUnit suite in qla2x00tgt.ko. Add KUnit cases for exhausted pools at word and non-word boundaries, an empty pool, unchanged guard words and reuse of the final valid tag. A spare guard word makes the old invalid access observable without needing an actual out-of-bounds access in the test fixture.
Overview
This is the source code repository of the SCST project. SCST is a collection of Linux kernel drivers that implement SCSI target functionality. The SCST project includes:
- The SCST core in the scst/ subdirectory.
- A tool for loading, saving and modifying the SCST configuration in directory scstadmin/.
- Several SCSI target drivers in the directories iscsi-scst/, qla2x00t-32gbit/, qla2x00t/, srpt/, scst_local/ and fcst/.
- User space programs in the usr/ subdirectory, e.g. fileio_tgt.
- Various documentation in the doc/ subdirectory.
Documentation
- Building and installing SCST.
- Build options: Clang, cross-compilation, and kernel module signing.
- Configuration and administration: targets, devices,
LUNs, and
/etc/scst.conf. - Core and device handlers: operating modes, module parameters, and sysfs configuration.
- Target drivers: iSCSI, iSER, QLogic Fibre Channel, SRP, FCoE, and local loopback.
- Performance tuning.
- Clustered persistent reservations: synchronization through DLM.
- T10 protection information: data integrity modes and configuration.
- Developer references: architecture and userspace handler interface (SGML sources), and sysfs interface rules.
- Contributing: code style, commit conventions, local checks, and guides to KUnit and component testing.
Current master packages
Prebuilt x86_64 packages from the latest successfully published master
build are available in the rolling
master-rpm prerelease.
These are development snapshots, not SCST releases.
The snapshot contains RPM bundles for selected Rocky Linux and Oracle Linux
UEK kernels. It also contains Ubuntu LTS bundles with scst-dkms, scstadmin
and iscsi-scst binary packages and their Debian source package files. Exact
distribution releases and RPM kernel versions are included in the asset names.
Every .tar.gz bundle has a matching .sha256 file. The complete snapshot is
replaced after each successful package workflow for the current master
commit.
QLogic target driver
Two QLogic target drivers are included in the SCST project.
The default driver is located in the qla2x00t-32gbit directory. It is the newer one.
May anyone wish to switch back to the older driver that only supported up to
16 Gb/s adapters, it is located in qla2x00t directory. To make use of the
older driver build scst with environment variable QLA_32GBIT=no set.
Vladislav Bolkhovitin vst@vlnb.net, http://scst.sourceforge.net
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