From: Peter Zijlstra <peterz@infradead.org>
To: Guangbo Cui <jckeep.cuiguangbo@gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Clark Williams <clrkwllms@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Bjorn Helgaas <bhelgaas@google.com>,
Waiman Long <longman@redhat.com>,
linux-rt-devel@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org
Subject: Re: [PATCH v4 2/2] PCI/aer_inject: Convert inject_lock to raw_spinlock_t
Date: Mon, 3 Nov 2025 20:21:20 +0100 [thread overview]
Message-ID: <20251103192120.GJ3419281@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20251102105706.7259-3-jckeep.cuiguangbo@gmail.com>
On Sun, Nov 02, 2025 at 10:57:06AM +0000, Guangbo Cui wrote:
> The AER injection path may run in interrupt-disabled context while
> holding inject_lock. On PREEMPT_RT kernels, spinlock_t becomes a
> sleeping lock, so it must not be taken while a raw_spinlock_t is held.
> Doing so violates lock ordering rules and trigger lockdep reports
> such as “Invalid wait context”.
>
> Convert inject_lock to raw_spinlock_t to ensure non-sleeping locking
> semantics. The protected list is bounded and used only for debugging,
> so raw locking will not cause latency issues.
Bounded how?
Also,
---
--- a/drivers/pci/pcie/aer_inject.c
+++ b/drivers/pci/pcie/aer_inject.c
@@ -85,12 +85,13 @@ static void aer_error_init(struct aer_er
err->pos_cap_err = pos_cap_err;
}
-/* inject_lock must be held before calling */
static struct aer_error *__find_aer_error(u32 domain, unsigned int bus,
unsigned int devfn)
{
struct aer_error *err;
+ lockdep_assert_held(&inject_lock);
+
list_for_each_entry(err, &einjected, list) {
if (domain == err->domain &&
bus == err->bus &&
@@ -100,20 +101,24 @@ static struct aer_error *__find_aer_erro
return NULL;
}
-/* inject_lock must be held before calling */
static struct aer_error *__find_aer_error_by_dev(struct pci_dev *dev)
{
- int domain = pci_domain_nr(dev->bus);
+ int domain;
+
+ lockdep_assert_held(&inject_lock);
+
+ domain = pci_domain_nr(dev->bus);
if (domain < 0)
return NULL;
return __find_aer_error(domain, dev->bus->number, dev->devfn);
}
-/* inject_lock must be held before calling */
static struct pci_ops *__find_pci_bus_ops(struct pci_bus *bus)
{
struct pci_bus_ops *bus_ops;
+ lockdep_assert_held(&inject_lock);
+
list_for_each_entry(bus_ops, &pci_bus_ops_list, list) {
if (bus_ops->bus == bus)
return bus_ops->ops;
next prev parent reply other threads:[~2025-11-03 19:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-02 10:57 [PATCH v4 0/2] PCI/aer_inject: Adjust locking for PREEMPT_RT Guangbo Cui
2025-11-02 10:57 ` [PATCH v4 1/2] PCI/aer_inject: Remove unnecessary lock in aer_inject_exit Guangbo Cui
2025-11-02 10:57 ` [PATCH v4 2/2] PCI/aer_inject: Convert inject_lock to raw_spinlock_t Guangbo Cui
2025-11-03 19:21 ` Peter Zijlstra [this message]
2025-11-03 19:27 ` Peter Zijlstra
2025-11-06 13:08 ` Guangbo Cui
2025-11-06 14:05 ` Peter Zijlstra
2025-11-11 14:39 ` Sebastian Andrzej Siewior
2025-11-03 20:02 ` Sebastian Andrzej Siewior
2025-11-03 20:29 ` Peter Zijlstra
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