[PATCH 5.15 114/917] soc: fsl: dpio: use the combined functions to protect critical zone

Greg Kroah-Hartman
2021-11-16T01:08:39Z

From: Meng Li <Meng.Li@windriver.com>

commit dc7e5940aad6641bd5ab33ea8b21c4b3904d989f upstream.

In orininal code, use 2 function spin_lock() and local_irq_save() to
protect the critical zone. But when enable the kernel debug config,
there are below inconsistent lock state detected.
================================
WARNING: inconsistent lock state
5.10.63-yocto-standard #1 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
lock_torture_wr/226 [HC0[0]:SC1[5]:HE1:SE0] takes:
ffff002005b2dd80 (&p->access_spinlock){+.?.}-{3:3}, at: qbman_swp_enqueue_multiple_mem_back+0x44/0x270
{SOFTIRQ-ON-W} state was registered at:
lock_acquire.part.0+0xf8/0x250
lock_acquire+0x68/0x84
_raw_spin_lock+0x68/0x90
qbman_swp_enqueue_multiple_mem_back+0x44/0x270
......
cryptomgr_test+0x38/0x60
kthread+0x158/0x164
ret_from_fork+0x10/0x38
irq event stamp: 4498
hardirqs last enabled at (4498): [<ffff800010fcf980>] _raw_spin_unlock_irqrestore+0x90/0xb0
hardirqs last disabled at (4497): [<ffff800010fcffc4>] _raw_spin_lock_irqsave+0xd4/0xe0
softirqs last enabled at (4458): [<ffff8000100108c4>] __do_softirq+0x674/0x724
softirqs last disabled at (4465): [<ffff80001005b2a4>] __irq_exit_rcu+0x190/0x19c

other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&p->access_spinlock);
<Interrupt>
lock(&p->access_spinlock);
*** DEADLOCK ***

So, in order to avoid deadlock, use the combined functions
spin_lock_irqsave/spin_unlock_irqrestore() to protect critical zone.

Fixes: 3b2abda7d28c ("soc: fsl: dpio: Replace QMAN array mode with ring mode enqueue")
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/soc/fsl/dpio/qbman-portal.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

--- a/drivers/soc/fsl/dpio/qbman-portal.c
+++ b/drivers/soc/fsl/dpio/qbman-portal.c
@@ -732,8 +732,7 @@ int qbman_swp_enqueue_multiple_mem_back(
int i, num_enqueued = 0;
unsigned long irq_flags;

- spin_lock(&s->access_spinlock);
- local_irq_save(irq_flags);
+ spin_lock_irqsave(&s->access_spinlock, irq_flags);

half_mask = (s->eqcr.pi_ci_mask>>1);
full_mask = s->eqcr.pi_ci_mask;
@@ -744,8 +743,7 @@ int qbman_swp_enqueue_multiple_mem_back(
s->eqcr.available = qm_cyc_diff(s->eqcr.pi_ring_size,
eqcr_ci, s->eqcr.ci);
if (!s->eqcr.available) {
- local_irq_restore(irq_flags);
- spin_unlock(&s->access_spinlock);
+ spin_unlock_irqrestore(&s->access_spinlock, irq_flags);
return 0;
}
}
@@ -784,8 +782,7 @@ int qbman_swp_enqueue_multiple_mem_back(
dma_wmb();
qbman_write_register(s, QBMAN_CINH_SWP_EQCR_PI,
(QB_RT_BIT)|(s->eqcr.pi)|s->eqcr.pi_vb);
- local_irq_restore(irq_flags);
- spin_unlock(&s->access_spinlock);
+ spin_unlock_irqrestore(&s->access_spinlock, irq_flags);

return num_enqueued;
}