The patch titled
Subject: mm/memory-failure: use raw_spinlock_t in struct memory_failure_cpu
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-memory-failure-use-raw_spinlock_t-in-struct-memory_failure_cpu.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-failure-use-raw_spinlock_t-in-struct-memory_failure_cpu.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Waiman Long <longman@xxxxxxxxxx>
Subject: mm/memory-failure: use raw_spinlock_t in struct memory_failure_cpu
Date: Tue, 6 Aug 2024 12:41:07 -0400
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.
Link: https://lkml.kernel.org/r/20240806164107.1044956-1-longman@xxxxxxxxxx
Fixes: ea8f5fb8a71f ("HWPoison: add memory_failure_queue()")
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-use-raw_spinlock_t-in-struct-memory_failure_cpu
+++ a/mm/memory-failure.c
@@ -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
{
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(str
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(vo
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);
}
_
Patches currently in -mm which might be from longman@xxxxxxxxxx are
padata-fix-possible-divide-by-0-panic-in-padata_mt_helper.patch
mm-memory-failure-use-raw_spinlock_t-in-struct-memory_failure_cpu.patch
watchdog-handle-the-enodev-failure-case-of-lockup_detector_delay_init-separately.patch
