GHSA-QM2M-CWG6-99V6
Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 12:31In the Linux kernel, the following vulnerability has been resolved:
pds_core: fix cmd_regs access racing BAR unmap on reset
pdsc_reset_prepare() and pdsc_reset_done()'s pdsc_map_bars() error path clear/iounmap cmd_regs without devcmd_lock, and pdsc_legacy_firmware_update()'s download loop derefs cmd_regs after dropping and retaking the lock without re-checking. An FLR concurrent with a devlink flash can unmap cmd_regs under an in-flight devcmd, causing a NULL deref or a write to unmapped MMIO.
Take devcmd_lock across the BAR unmap/remap, and re-check cmd_regs in the download loop. Only the PF maps cmd_regs and runs devcmd, so skip the unmap on a VF, as pdsc_remove() and pdsc_reset_done() already do.
A reset that completes entirely within the unlocked window is not a correctness problem for the image: the device clears its update session, so a resumed download is rejected, and it verifies the staged image before writing a flash slot, reporting PDS_RC_BAD_FW rather than activating it.
pdsc_unmap_bars() also clears info_regs, intr_status and intr_ctrl. The interrupt and start/stop readers of those are quiesced before the unmap by pdsc_fw_down(), which frees the interrupts and tears down the queues. The debugfs readers are not, since those files outlive a reset; that is pre-existing and out of scope here.
{
"affected": [],
"aliases": [
"CVE-2026-98020"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-25T11:17:30Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npds_core: fix cmd_regs access racing BAR unmap on reset\n\npdsc_reset_prepare() and pdsc_reset_done()\u0027s pdsc_map_bars() error path\nclear/iounmap cmd_regs without devcmd_lock, and\npdsc_legacy_firmware_update()\u0027s download loop derefs cmd_regs after\ndropping and retaking the lock without re-checking. An FLR concurrent\nwith a devlink flash can unmap cmd_regs under an in-flight devcmd,\ncausing a NULL deref or a write to unmapped MMIO.\n\nTake devcmd_lock across the BAR unmap/remap, and re-check cmd_regs in\nthe download loop. Only the PF maps cmd_regs and runs devcmd, so skip\nthe unmap on a VF, as pdsc_remove() and pdsc_reset_done() already do.\n\nA reset that completes entirely within the unlocked window is not a\ncorrectness problem for the image: the device clears its update session,\nso a resumed download is rejected, and it verifies the staged image\nbefore writing a flash slot, reporting PDS_RC_BAD_FW rather than\nactivating it.\n\npdsc_unmap_bars() also clears info_regs, intr_status and intr_ctrl. The\ninterrupt and start/stop readers of those are quiesced before the unmap\nby pdsc_fw_down(), which frees the interrupts and tears down the queues.\nThe debugfs readers are not, since those files outlive a reset; that is\npre-existing and out of scope here.",
"id": "GHSA-qm2m-cwg6-99v6",
"modified": "2026-09-25T12:31:33Z",
"published": "2026-09-25T12:31:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98020"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/09f831bfe39de5b8026fefb3d106b5cc93272170"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2cc697565fd19b5ba2d100cdd4a20dd6d263abc2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7980325b2f71e3f65c1323c39792e2455da6fab6"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fa31bd14c5042c6315bb2182c963f03ca6e79ca4"
}
],
"schema_version": "1.4.0",
"severity": []
}
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