published December 8, 2025
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: mcq: Fix &hwq->cq_lock deadlock issue
When ufshcd_err_handler() is executed, CQ event interrupt can enter waiting
for the same lock. This can happen in ufshcd_handle_mcq_cq_events() and
also in ufs_mtk_mcq_intr(). The following warning message will be generated
when &hwq->cq_lock is used in IRQ context with IRQ enabled. Use
ufshcd_mcq_poll_cqe_lock() with spin_lock_irqsave instead of spin_lock to
resolve the deadlock issue.
[name:lockdep&]WARNING: inconsistent lock state
[name:lockdep&]--------------------------------
[name:lockdep&]inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[name:lockdep&]kworker/u16:4/260 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffffff8028444600 (&hwq->cq_lock){?.-.}-{2:2}, at:
ufshcd_mcq_poll_cqe_lock+0x30/0xe0
[name:lockdep&]{IN-HARDIRQ-W} state was registered at:
lock_acquire+0x17c/0x33c
_raw_spin_lock+0x5c/0x7c
ufshcd_mcq_poll_cqe_lock+0x30/0xe0
ufs_mtk_mcq_intr+0x60/0x1bc [ufs_mediatek_mod]
__handle_irq_event_percpu+0x140/0x3ec
handle_irq_event+0x50/0xd8
handle_fasteoi_irq+0x148/0x2b0
generic_handle_domain_irq+0x4c/0x6c
gic_handle_irq+0x58/0x134
call_on_irq_stack+0x40/0x74
do_interrupt_handler+0x84/0xe4
el1_interrupt+0x3c/0x78
<snip>
Possible unsafe locking scenario:
CPU0
----
lock(&hwq->cq_lock);
<Interrupt>
lock(&hwq->cq_lock);
*** DEADLOCK ***
2 locks held by kworker/u16:4/260:
[name:lockdep&]
stack backtrace:
CPU: 7 PID: 260 Comm: kworker/u16:4 Tainted: G S W OE
6.1.17-mainline-android14-2-g277223301adb #1
Workqueue: ufs_eh_wq_0 ufshcd_err_handler
Call trace:
dump_backtrace+0x10c/0x160
show_stack+0x20/0x30
dump_stack_lvl+0x98/0xd8
dump_stack+0x20/0x60
print_usage_bug+0x584/0x76c
mark_lock_irq+0x488/0x510
mark_lock+0x1ec/0x25c
__lock_acquire+0x4d8/0xffc
lock_acquire+0x17c/0x33c
_raw_spin_lock+0x5c/0x7c
ufshcd_mcq_poll_cqe_lock+0x30/0xe0
ufshcd_poll+0x68/0x1b0
ufshcd_transfer_req_compl+0x9c/0xc8
ufshcd_err_handler+0x3bc/0xea0
process_one_work+0x2f4/0x7e8
worker_thread+0x234/0x450
kthread+0x110/0x134
ret_from_fork+0x10/0x20