Subject: CVE-2021-47271: usb: cdnsp: Fix deadlock issue in cdnsp_thread_irq_handler

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

usb: cdnsp: Fix deadlock issue in cdnsp_thread_irq_handler

Patch fixes the following critical issue caused by deadlock which has been
detected during testing NCM class:

smp: csd: Detected non-responsive CSD lock (#1) on CPU#0
smp:     csd: CSD lock (#1) unresponsive.
....
RIP: 0010:native_queued_spin_lock_slowpath+0x61/0x1d0
RSP: 0018:ffffbc494011cde0 EFLAGS: 00000002
RAX: 0000000000000101 RBX: ffff9ee8116b4a68 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9ee8116b4658
RBP: ffffbc494011cde0 R08: 0000000000000001 R09: 0000000000000000
R10: ffff9ee8116b4670 R11: 0000000000000000 R12: ffff9ee8116b4658
R13: ffff9ee8116b4670 R14: 0000000000000246 R15: ffff9ee8116b4658
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7bcc41a830 CR3: 000000007a612003 CR4: 00000000001706e0
Call Trace:
 <IRQ>
 do_raw_spin_lock+0xc0/0xd0
 _raw_spin_lock_irqsave+0x95/0xa0
 cdnsp_gadget_ep_queue.cold+0x88/0x107 [cdnsp_udc_pci]
 usb_ep_queue+0x35/0x110
 eth_start_xmit+0x220/0x3d0 [u_ether]
 ncm_tx_timeout+0x34/0x40 [usb_f_ncm]
 ? ncm_free_inst+0x50/0x50 [usb_f_ncm]
 __hrtimer_run_queues+0xac/0x440
 hrtimer_run_softirq+0x8c/0xb0
 __do_softirq+0xcf/0x428
 asm_call_irq_on_stack+0x12/0x20
 </IRQ>
 do_softirq_own_stack+0x61/0x70
 irq_exit_rcu+0xc1/0xd0
 sysvec_apic_timer_interrupt+0x52/0xb0
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:do_raw_spin_trylock+0x18/0x40
RSP: 0018:ffffbc494138bda8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff9ee8116b4658 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff9ee8116b4658
RBP: ffffbc494138bda8 R08: 0000000000000001 R09: 0000000000000000
R10: ffff9ee8116b4670 R11: 0000000000000000 R12: ffff9ee8116b4658
R13: ffff9ee8116b4670 R14: ffff9ee7b5c73d80 R15: ffff9ee8116b4000
 _raw_spin_lock+0x3d/0x70
 ? cdnsp_thread_irq_handler.cold+0x32/0x112c [cdnsp_udc_pci]
 cdnsp_thread_irq_handler.cold+0x32/0x112c [cdnsp_udc_pci]
 ? cdnsp_remove_request+0x1f0/0x1f0 [cdnsp_udc_pci]
 ? cdnsp_thread_irq_handler+0x5/0xa0 [cdnsp_udc_pci]
 ? irq_thread+0xa0/0x1c0
 irq_thread_fn+0x28/0x60
 irq_thread+0x105/0x1c0
 ? __kthread_parkme+0x42/0x90
 ? irq_forced_thread_fn+0x90/0x90
 ? wake_threads_waitq+0x30/0x30
 ? irq_thread_check_affinity+0xe0/0xe0
 kthread+0x12a/0x160
 ? kthread_park+0x90/0x90
 ret_from_fork+0x22/0x30

The root cause of issue is spin_lock/spin_unlock instruction instead
spin_lock_irqsave/spin_lock_irqrestore in cdnsp_thread_irq_handler
function.

The Linux kernel CVE team has assigned CVE-2021-47271 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.12 with commit 3d82904559f4 and fixed in 5.12.11 with commit ae746b6f4ce6
	Issue introduced in 5.12 with commit 3d82904559f4 and fixed in 5.13 with commit a9aecef198fa

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2021-47271
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/usb/cdns3/cdnsp-ring.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/ae746b6f4ce619cf4032fd798a232b010907a397
	https://git.kernel.org/stable/c/a9aecef198faae3240921b707bc09b602e966fce