CVE-2026-64103scsi: isci: Fix use-after-free in device removal path

Official description

In the Linux kernel, the following vulnerability has been resolved: scsi: isci: Fix use-after-free in device removal path The ISCI completion tasklet is initialized in isci_host_alloc() (drivers/scsi/isci/init.c:496) and scheduled from both MSI-X and legacy interrupt handlers (drivers/scsi/isci/host.c:223,613). isci_host_deinit() stops the controller and waits for stop completion, but it never kills completion_tasklet before teardown continues. A top-of-function tasklet_kill() is not sufficient here: interrupts are only disabled when isci_host_stop_complete() runs, so until wait_for_stop() returns the IRQ handlers can still requeue the tasklet. The tasklet callback also re-enables interrupts after draining completions, so killing the tasklet before the source is quiesced leaves the same race open. Once wait_for_stop() returns, no further IRQ-driven scheduling can occur. Kill completion_tasklet there so teardown cannot race a queued tasklet running on a dead ihost. On remove or unload, the stale callback can otherwise dereference ihost and touch ihost->smu_registers after the host lifetime ends. A UML + KASAN analogue reproduced the failure class both with no tasklet_kill() and with tasklet_kill() placed before source quiesce, and stayed clean once the kill happened after quiescing the scheduling source. This mirrors commit f6ab594672d4 ("scsi: aic94xx: fix use-after-free in device removal path"), but ISCI needs the kill after wait_for_stop().

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/1412995e10c74644b47f242aea6e4f3d4180e806
• https://git.kernel.org/stable/c/a83d3e4daba40d49324cec1c51ed261e1ea48cf1
• https://git.kernel.org/stable/c/ab2266601a875982f2d2033f41e070a6d5e615e2
• https://git.kernel.org/stable/c/309c6058622d080fe8c2fab87c30da82d834d989
• https://git.kernel.org/stable/c/cb9e72c50e6c81a5903f27e0b397ce8525d7539b
• https://git.kernel.org/stable/c/b9ff8631006233ba246828ac70409d2cb2da38d3
• https://git.kernel.org/stable/c/6d40f2f103bb30f52f3dbadbe2c3fdf274a9763c
• https://git.kernel.org/stable/c/b52a8d52c3125ec9a93106ed816582368de34426