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CVE-2026-74555

scsi: libsas: Fix HA resume deadlock and hisi_sas disk-wake race

EPSS 0.2%

Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/scsi. Debian urgency: not yet assigned.

What to do, per Debian release

Debian's own status for CVE-2026-74555 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source

ReleaseStatus VersionWhat this means
Debian 12bookwormfixedDLA-4777-1 · 2026-09-08 · text6.1.187-1Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts.
Debian 13trixiefixedDSA-6466-1 · 2026-08-25 · text6.12.105-1Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts.
Debian 14forkyfixed7.1.8-1Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts.
Debian unstablesidfixed7.1.8-1Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts.
Debian 12bookworm · linux-6.12fixedDLA-4788-1 · 2026-09-19 · text6.12.107-1~deb12u1Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts.

The vulnerability

What the bug is

Commit fbefe22811c3 ("scsi: libsas: Don't always drain event workqueue for HA resume") introduced sas_resume_ha_no_sync() to avoid a deadlock: the PHYE_RESUME_TIMEOUT handler, running on the HA event workqueue, calls sas_deform_port() -> sas_destruct_devices(), which removes SCSI devices and waits for the host to become runtime-active. But the host cannot resume until sas_resume_ha() -> sas_drain_work() returns, and the drain is blocked on that very handler. However skipping the drain reintroduces a race: hisi_sas returns from resume before all PHY UP work and libsas discovery work finish. The controller may then autosuspend while disks are still waking up. The disks issue IO to a suspended controller, the IO fails, and the disks get disabled. Fix the deadlock at its source by moving the PHYE_RESUME_TIMEOUT notification to after sas_drain_work(). By then the host resume is about to complete, so device removal through device_link no longer blocks on the resume and the cycle is broken. With the deadlock gone, restore sas_resume_ha() (the draining variant) in hisi_sas and remove sas_resume_ha_no_sync(). The reorder is safe for the other libsas consumers (isci, pm8001, aic94xx, mvsas). During suspend, sas_suspend_devices() calls sas_notify_lldd_dev_gone() for each device, which sets dev->lldd_dev to NULL. When scsi_unblock_requests re-enables I/O in resume, any I/O to a timed-out phy's disk is immediately rejected by the LLDD before reaching hardware: isci returns SAS_DEVICE_UNKNOWN (mapped to DID_BAD_TARGET), and pm8001 returns SAS_PHY_DOWN (mapped to DID_NO_CONNECT). Both complete directly via scsi_done() without entering SCSI EH. This is identical in both the old and new ordering since lldd_dev_gone runs during suspend, before resume. The reorder only affects when the PHYE_RESUME_TIMEOUT handler runs (synchronized by sas_drain_work() vs. asynchronous after resume returns), not whether I/O can reach the device. aic94xx and mvsas do not register any PM ops and never reach this code path.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
drivers/scsi/libsas/sas_init.c
include/scsi/libsas.h

What this is
HISILICON SAS ControllerMAINTAINERS section matched on drivers/scsi/hisi_sas/ · Supported
Kernel module
hisi_sas_v3_hw

Check it on the machine

grep -wE 'CONFIG_SCSI_HISI_SAS|CONFIG_SCSI_HISI_SAS_PCI' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w hisi_sas_v3_hw

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

  • bookwormMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
  • trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
  • forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
  • bookworm · linux-6.12Mnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
M
a module where it is built at all; some flavours do not build it
Build switches
CONFIG_SCSI_HISI_SAS, CONFIG_SCSI_HISI_SAS_PCI
Reads as
all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published
2026-08-15 (2 months ago)source
CVSS
no vector published, unrated
Attack vector
not published
EPSS
0.16%, higher than 4.9% of all CVEssource
CISA KEV
not listedthe KEV catalogue
Debian urgency
not yet assignedsource
Subsystem
drivers/scsi

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

IntroducedFixed inCommit
5.176.1.18309357f067122
5.176.6.151e50a6523a603
5.176.12.103c391b5899dd4
5.176.18.449e24b47ef81d
5.177.1.8b9c44a140620
5.177.23dbbbf656b85

Debian advisories

AdvisoryDateShipped toDebian
DLA-4788-12026-09-19bookworm 6.12.107-1~deb12u1tracker
DLA-4777-12026-09-08bookworm 6.1.187-1tracker
DSA-6466-12026-08-25trixie 6.12.105-1tracker

Why the CNA scored it this way

The kernel CNA published no CVSS vector and no reasoning for CVE-2026-74555, which is why it is shown as unrated rather than given an invented score. 6,405 of the 20,413 CVEs here carry reasoning; this is not one of them.