This is a note to let you know that I've just added the patch titled
ACPI: CPPC: Make rmw_lock a raw_spin_lock
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-cppc-make-rmw_lock-a-raw_spin_lock.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2eb08ff8771115962592a1d83300c2314d5090b9
Author: Pierre Gondois <pierre.gondois@xxxxxxx>
Date: Mon Oct 28 13:56:56 2024 +0100
ACPI: CPPC: Make rmw_lock a raw_spin_lock
[ Upstream commit 1c10941e34c5fdc0357e46a25bd130d9cf40b925 ]
The following BUG was triggered:
=============================
[ BUG: Invalid wait context ]
6.12.0-rc2-XXX #406 Not tainted
-----------------------------
kworker/1:1/62 is trying to lock:
ffffff8801593030 (&cpc_ptr->rmw_lock){+.+.}-{3:3}, at: cpc_write+0xcc/0x370
other info that might help us debug this:
context-{5:5}
2 locks held by kworker/1:1/62:
#0: ffffff897ef5ec98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x50
#1: ffffff880154e238 (&sg_policy->update_lock){....}-{2:2}, at: sugov_update_shared+0x3c/0x280
stack backtrace:
CPU: 1 UID: 0 PID: 62 Comm: kworker/1:1 Not tainted 6.12.0-rc2-g9654bd3e8806 #406
Workqueue: 0x0 (events)
Call trace:
dump_backtrace+0xa4/0x130
show_stack+0x20/0x38
dump_stack_lvl+0x90/0xd0
dump_stack+0x18/0x28
__lock_acquire+0x480/0x1ad8
lock_acquire+0x114/0x310
_raw_spin_lock+0x50/0x70
cpc_write+0xcc/0x370
cppc_set_perf+0xa0/0x3a8
cppc_cpufreq_fast_switch+0x40/0xc0
cpufreq_driver_fast_switch+0x4c/0x218
sugov_update_shared+0x234/0x280
update_load_avg+0x6ec/0x7b8
dequeue_entities+0x108/0x830
dequeue_task_fair+0x58/0x408
__schedule+0x4f0/0x1070
schedule+0x54/0x130
worker_thread+0xc0/0x2e8
kthread+0x130/0x148
ret_from_fork+0x10/0x20
sugov_update_shared() locks a raw_spinlock while cpc_write() locks a
spinlock.
To have a correct wait-type order, update rmw_lock to a raw spinlock and
ensure that interrupts will be disabled on the CPU holding it.
Fixes: 60949b7b8054 ("ACPI: CPPC: Fix MASK_VAL() usage")
Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
Link: https://patch.msgid.link/20241028125657.1271512-1-pierre.gondois@xxxxxxx
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 8d14e6c705357..0e9ccedb08dab 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -813,7 +813,7 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
/* Store CPU Logical ID */
cpc_ptr->cpu_id = pr->id;
- spin_lock_init(&cpc_ptr->rmw_lock);
+ raw_spin_lock_init(&cpc_ptr->rmw_lock);
/* Parse PSD data for this CPU */
ret = acpi_get_psd(cpc_ptr, handle);
@@ -1020,6 +1020,7 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cpc_reg *reg = ®_res->cpc_entry.reg;
struct cpc_desc *cpc_desc;
+ unsigned long flags;
size = GET_BIT_WIDTH(reg);
@@ -1047,7 +1048,7 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
return -ENODEV;
}
- spin_lock(&cpc_desc->rmw_lock);
+ raw_spin_lock_irqsave(&cpc_desc->rmw_lock, flags);
switch (size) {
case 8:
prev_val = readb_relaxed(vaddr);
@@ -1062,7 +1063,7 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
prev_val = readq_relaxed(vaddr);
break;
default:
- spin_unlock(&cpc_desc->rmw_lock);
+ raw_spin_unlock_irqrestore(&cpc_desc->rmw_lock, flags);
return -EFAULT;
}
val = MASK_VAL_WRITE(reg, prev_val, val);
@@ -1095,7 +1096,7 @@ static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
}
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
- spin_unlock(&cpc_desc->rmw_lock);
+ raw_spin_unlock_irqrestore(&cpc_desc->rmw_lock, flags);
return ret_val;
}
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index 0fed87e2a8959..28179bb794b2f 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -65,7 +65,7 @@ struct cpc_desc {
int write_cmd_status;
int write_cmd_id;
/* Lock used for RMW operations in cpc_write() */
- spinlock_t rmw_lock;
+ raw_spinlock_t rmw_lock;
struct cpc_register_resource cpc_regs[MAX_CPC_REG_ENT];
struct acpi_psd_package domain_info;
struct kobject kobj;
