On 2024/8/8 2:11, Waiman Long wrote:
> 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 and after
> put_cpu_ptr() to avoid indeterminate latency and the possibility of
> sleep with this call.
>
> Fixes: 0f383b6dc96e ("locking/spinlock: Provide RT variant")
> Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
LGTM. Thanks.
Acked-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Thanks.
.
