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ACPI: CPPC: Make rmw_lock a raw_spin_lock

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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: 60949b7b80 ("ACPI: CPPC: Fix MASK_VAL() usage")
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://patch.msgid.link/20241028125657.1271512-1-pierre.gondois@arm.com
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Pierre Gondois 2024-10-28 13:56:56 +01:00 committed by Rafael J. Wysocki
parent 8198375843
commit 1c10941e34
2 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/acpi/cppc_acpi.c
View File

@ -867,7 +867,7 @@ 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);
@ -1087,6 +1087,7 @@ 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 = &reg_res->cpc_entry.reg;
struct cpc_desc *cpc_desc;
unsigned long flags;
size = GET_BIT_WIDTH(reg);
@ -1126,7 +1127,7 @@ 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);
@ -1141,7 +1142,7 @@ 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);
@ -1174,7 +1175,7 @@ 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;
}

2
include/acpi/cppc_acpi.h
View File

@ -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;