@@ -2417,7 +2417,7 @@ struct memory_failure_entry {
struct memory_failure_cpu {
DECLARE_KFIFO(fifo, struct memory_failure_entry,
MEMORY_FAILURE_FIFO_SIZE);
- spinlock_t lock;
+ raw_spinlock_t lock;
struct work_struct work;
};
@@ -2443,19 +2443,21 @@ void memory_failure_queue(unsigned long pfn, int flags)
{
struct memory_failure_cpu *mf_cpu;
unsigned long proc_flags;
+ bool buffer_overflow;
struct memory_failure_entry entry = {
.pfn = pfn,
.flags = flags,
};
mf_cpu = &get_cpu_var(memory_failure_cpu);
- spin_lock_irqsave(&mf_cpu->lock, proc_flags);
- if (kfifo_put(&mf_cpu->fifo, entry))
+ raw_spin_lock_irqsave(&mf_cpu->lock, proc_flags);
+ buffer_overflow = !kfifo_put(&mf_cpu->fifo, entry);
+ if (!buffer_overflow)
schedule_work_on(smp_processor_id(), &mf_cpu->work);
- else
+ raw_spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
+ if (buffer_overflow)
pr_err("buffer overflow when queuing memory failure at %#lx\n",
pfn);
- spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
put_cpu_var(memory_failure_cpu);
}
EXPORT_SYMBOL_GPL(memory_failure_queue);
@@ -2469,9 +2471,9 @@ static void memory_failure_work_func(struct work_struct *work)
mf_cpu = container_of(work, struct memory_failure_cpu, work);
for (;;) {
- spin_lock_irqsave(&mf_cpu->lock, proc_flags);
+ raw_spin_lock_irqsave(&mf_cpu->lock, proc_flags);
gotten = kfifo_get(&mf_cpu->fifo, &entry);
- spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
+ raw_spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
if (!gotten)
break;
if (entry.flags & MF_SOFT_OFFLINE)
@@ -2501,7 +2503,7 @@ static int __init memory_failure_init(void)
for_each_possible_cpu(cpu) {
mf_cpu = &per_cpu(memory_failure_cpu, cpu);
- spin_lock_init(&mf_cpu->lock);
+ raw_spin_lock_init(&mf_cpu->lock);
INIT_KFIFO(mf_cpu->fifo);
INIT_WORK(&mf_cpu->work, memory_failure_work_func);
}
The memory_failure_cpu structure is a per-cpu structure. Access to its content requires the use of get_cpu_var() to lock in the current CPU and disable preemption. The use of a regular spinlock_t for locking purpose is fine for a non-RT kernel. Since the integration of RT spinlock support into the v5.15 kernel, a spinlock_t in a RT kernel becomes a sleeping lock and taking a sleeping lock in a preemption disabled context is illegal resulting in the following kind of warning. [12135.732244] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 [12135.732248] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 270076, name: kworker/0:0 [12135.732252] preempt_count: 1, expected: 0 [12135.732255] RCU nest depth: 2, expected: 2 : [12135.732420] Hardware name: Dell Inc. PowerEdge R640/0HG0J8, BIOS 2.10.2 02/24/2021 [12135.732423] Workqueue: kacpi_notify acpi_os_execute_deferred [12135.732433] Call Trace: [12135.732436] <TASK> [12135.732450] dump_stack_lvl+0x57/0x81 [12135.732461] __might_resched.cold+0xf4/0x12f [12135.732479] rt_spin_lock+0x4c/0x100 [12135.732491] memory_failure_queue+0x40/0xe0 [12135.732503] ghes_do_memory_failure+0x53/0x390 [12135.732516] ghes_do_proc.constprop.0+0x229/0x3e0 [12135.732575] ghes_proc+0xf9/0x1a0 [12135.732591] ghes_notify_hed+0x6a/0x150 [12135.732602] notifier_call_chain+0x43/0xb0 [12135.732626] blocking_notifier_call_chain+0x43/0x60 [12135.732637] acpi_ev_notify_dispatch+0x47/0x70 [12135.732648] acpi_os_execute_deferred+0x13/0x20 [12135.732654] process_one_work+0x41f/0x500 [12135.732695] worker_thread+0x192/0x360 [12135.732715] kthread+0x111/0x140 [12135.732733] ret_from_fork+0x29/0x50 [12135.732779] </TASK> Fix it by using a raw_spinlock_t for locking instead. Also move the pr_err() out of the lock critical section to avoid indeterminate latency of this call. Fixes: ea8f5fb8a71f ("HWPoison: add memory_failure_queue()") Signed-off-by: Waiman Long <longman@redhat.com> --- mm/memory-failure.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)