GHSA-MF6R-PGPM-MQVQ
Vulnerability from github – Published: 2026-05-01 15:30 – Updated: 2026-05-07 18:30In the Linux kernel, the following vulnerability has been resolved:
scsi: target: tcm_loop: Drain commands in target_reset handler
tcm_loop_target_reset() violates the SCSI EH contract: it returns SUCCESS without draining any in-flight commands. The SCSI EH documentation (scsi_eh.rst) requires that when a reset handler returns SUCCESS the driver has made lower layers "forget about timed out scmds" and is ready for new commands. Every other SCSI LLD (virtio_scsi, mpt3sas, ipr, scsi_debug, mpi3mr) enforces this by draining or completing outstanding commands before returning SUCCESS.
Because tcm_loop_target_reset() doesn't drain, the SCSI EH reuses in-flight scsi_cmnd structures for recovery commands (e.g. TUR) while the target core still has async completion work queued for the old se_cmd. The memset in queuecommand zeroes se_lun and lun_ref_active, causing transport_lun_remove_cmd() to skip its percpu_ref_put(). The leaked LUN reference prevents transport_clear_lun_ref() from completing, hanging configfs LUN unlink forever in D-state:
INFO: task rm:264 blocked for more than 122 seconds. rm D 0 264 258 0x00004000 Call Trace: __schedule+0x3d0/0x8e0 schedule+0x36/0xf0 transport_clear_lun_ref+0x78/0x90 [target_core_mod] core_tpg_remove_lun+0x28/0xb0 [target_core_mod] target_fabric_port_unlink+0x50/0x60 [target_core_mod] configfs_unlink+0x156/0x1f0 [configfs] vfs_unlink+0x109/0x290 do_unlinkat+0x1d5/0x2d0
Fix this by making tcm_loop_target_reset() actually drain commands:
-
Issue TMR_LUN_RESET via tcm_loop_issue_tmr() to drain all commands that the target core knows about (those not yet CMD_T_COMPLETE).
-
Use blk_mq_tagset_busy_iter() to iterate all started requests and flush_work() on each se_cmd — this drains any deferred completion work for commands that already had CMD_T_COMPLETE set before the TMR (which the TMR skips via __target_check_io_state()). This is the same pattern used by mpi3mr, scsi_debug, and libsas to drain outstanding commands during reset.
{
"affected": [],
"aliases": [
"CVE-2026-43054"
],
"database_specific": {
"cwe_ids": [
"CWE-772"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-01T15:16:51Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: target: tcm_loop: Drain commands in target_reset handler\n\ntcm_loop_target_reset() violates the SCSI EH contract: it returns SUCCESS\nwithout draining any in-flight commands. The SCSI EH documentation\n(scsi_eh.rst) requires that when a reset handler returns SUCCESS the driver\nhas made lower layers \"forget about timed out scmds\" and is ready for new\ncommands. Every other SCSI LLD (virtio_scsi, mpt3sas, ipr, scsi_debug,\nmpi3mr) enforces this by draining or completing outstanding commands before\nreturning SUCCESS.\n\nBecause tcm_loop_target_reset() doesn\u0027t drain, the SCSI EH reuses in-flight\nscsi_cmnd structures for recovery commands (e.g. TUR) while the target core\nstill has async completion work queued for the old se_cmd. The memset in\nqueuecommand zeroes se_lun and lun_ref_active, causing\ntransport_lun_remove_cmd() to skip its percpu_ref_put(). The leaked LUN\nreference prevents transport_clear_lun_ref() from completing, hanging\nconfigfs LUN unlink forever in D-state:\n\n INFO: task rm:264 blocked for more than 122 seconds.\n rm D 0 264 258 0x00004000\n Call Trace:\n __schedule+0x3d0/0x8e0\n schedule+0x36/0xf0\n transport_clear_lun_ref+0x78/0x90 [target_core_mod]\n core_tpg_remove_lun+0x28/0xb0 [target_core_mod]\n target_fabric_port_unlink+0x50/0x60 [target_core_mod]\n configfs_unlink+0x156/0x1f0 [configfs]\n vfs_unlink+0x109/0x290\n do_unlinkat+0x1d5/0x2d0\n\nFix this by making tcm_loop_target_reset() actually drain commands:\n\n 1. Issue TMR_LUN_RESET via tcm_loop_issue_tmr() to drain all commands that\n the target core knows about (those not yet CMD_T_COMPLETE).\n\n 2. Use blk_mq_tagset_busy_iter() to iterate all started requests and\n flush_work() on each se_cmd \u2014 this drains any deferred completion work\n for commands that already had CMD_T_COMPLETE set before the TMR (which\n the TMR skips via __target_check_io_state()). This is the same pattern\n used by mpi3mr, scsi_debug, and libsas to drain outstanding commands\n during reset.",
"id": "GHSA-mf6r-pgpm-mqvq",
"modified": "2026-05-07T18:30:35Z",
"published": "2026-05-01T15:30:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43054"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/05ac3754467363558a0a54ae4bb7c89b2c9574cf"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/103f79e4949513247d763c6e7f3cbbf62017afdf"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1333eee56cdf3f0cf67c6ab4114c2c9e0a952026"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/15f5241d5a52364a7e7867b49128b0442dbcad9d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/757c43c692294cdfad31390accc0e90429b2ef8a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7cbd69aaa507b1245240a28022bf5da0f07c68d9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a836054ea81014117ec6b73529a21626a9e1f829"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
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