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Subject[PATCH] ACPI / CPPC: FIX KASAN global out of bounds warning
Date
Default value of pcc_subspace_idx is -1.
Make sure to check pcc_subspace_idx before using the same as array index.
This will avoid following KASAN warnings too.

[ 15.113449] ==================================================================
[ 15.116983] BUG: KASAN: global-out-of-bounds in cppc_get_perf_caps+0xf3/0x3b0
[ 15.116983] Read of size 8 at addr ffffffffb9a5c0d8 by task swapper/0/1
[ 15.116983] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc2+ #2
[ 15.116983] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.2.8 01/26/2016
[ 15.116983] Call Trace:
[ 15.116983] dump_stack+0x7c/0xbb
[ 15.116983] print_address_description+0x1df/0x290
[ 15.116983] kasan_report+0x28a/0x370
[ 15.116983] ? cppc_get_perf_caps+0xf3/0x3b0
[ 15.116983] cppc_get_perf_caps+0xf3/0x3b0
[ 15.116983] ? cpc_read+0x210/0x210
[ 15.116983] ? __rdmsr_on_cpu+0x90/0x90
[ 15.116983] ? rdmsrl_on_cpu+0xa9/0xe0
[ 15.116983] ? rdmsr_on_cpu+0x100/0x100
[ 15.116983] ? wrmsrl_on_cpu+0x9c/0xd0
[ 15.116983] ? wrmsrl_on_cpu+0x9c/0xd0
[ 15.116983] ? wrmsr_on_cpu+0xe0/0xe0
[ 15.116983] __intel_pstate_cpu_init.part.16+0x3a2/0x530
[ 15.116983] ? intel_pstate_init_cpu+0x197/0x390
[ 15.116983] ? show_no_turbo+0xe0/0xe0
[ 15.116983] ? __lockdep_init_map+0xa0/0x290
[ 15.116983] intel_pstate_cpu_init+0x30/0x60
[ 15.116983] cpufreq_online+0x155/0xac0
[ 15.116983] cpufreq_add_dev+0x9b/0xb0
[ 15.116983] subsys_interface_register+0x1ae/0x290
[ 15.116983] ? bus_unregister_notifier+0x40/0x40
[ 15.116983] ? mark_held_locks+0x83/0xb0
[ 15.116983] ? _raw_write_unlock_irqrestore+0x32/0x60
[ 15.116983] ? intel_pstate_setup+0xc/0x104
[ 15.116983] ? intel_pstate_setup+0xc/0x104
[ 15.116983] ? cpufreq_register_driver+0x1ce/0x2b0
[ 15.116983] cpufreq_register_driver+0x1ce/0x2b0
[ 15.116983] ? intel_pstate_setup+0x104/0x104
[ 15.116983] intel_pstate_register_driver+0x3a/0xa0
[ 15.116983] intel_pstate_init+0x3c4/0x434
[ 15.116983] ? intel_pstate_setup+0x104/0x104
[ 15.116983] ? intel_pstate_setup+0x104/0x104
[ 15.116983] do_one_initcall+0x9c/0x206
[ 15.116983] ? parameq+0xa0/0xa0
[ 15.116983] ? initcall_blacklisted+0x150/0x150
[ 15.116983] ? lock_downgrade+0x2c0/0x2c0
[ 15.116983] kernel_init_freeable+0x327/0x3f0
[ 15.116983] ? start_kernel+0x612/0x612
[ 15.116983] ? _raw_spin_unlock_irq+0x29/0x40
[ 15.116983] ? finish_task_switch+0xdd/0x320
[ 15.116983] ? finish_task_switch+0x8e/0x320
[ 15.116983] ? rest_init+0xd0/0xd0
[ 15.116983] kernel_init+0xf/0x11a
[ 15.116983] ? rest_init+0xd0/0xd0
[ 15.116983] ret_from_fork+0x24/0x30

[ 15.116983] The buggy address belongs to the variable:
[ 15.116983] __key.36299+0x38/0x40

[ 15.116983] Memory state around the buggy address:
[ 15.116983] ffffffffb9a5bf80: fa fa fa fa 00 fa fa fa fa fa fa fa 00 fa fa fa
[ 15.116983] ffffffffb9a5c000: fa fa fa fa 00 fa fa fa fa fa fa fa 00 fa fa fa
[ 15.116983] >ffffffffb9a5c080: fa fa fa fa 00 fa fa fa fa fa fa fa 00 00 00 00
[ 15.116983] ^
[ 15.116983] ffffffffb9a5c100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 15.116983] ffffffffb9a5c180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 15.116983] ==================================================================

Reported-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: George Cherian <george.cherian@cavium.com>
---
drivers/acpi/cppc_acpi.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index 21c2843..30e84cc 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -949,7 +949,7 @@ static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
}

*val = 0;
- if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
+ if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
vaddr = reg_res->sys_mem_vaddr;
@@ -988,7 +988,7 @@ 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;

- if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM)
+ if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
vaddr = reg_res->sys_mem_vaddr;
@@ -1035,14 +1035,15 @@ int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
*lowest_non_linear_reg, *nominal_reg;
u64 high, low, nom, min_nonlinear;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
- struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
+ struct cppc_pcc_data *pcc_ss_data;
int ret = 0, regs_in_pcc = 0;

- if (!cpc_desc) {
+ if (!cpc_desc || pcc_ss_id < 0) {
pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
return -ENODEV;
}

+ pcc_ss_data = pcc_data[pcc_ss_id];
highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
@@ -1095,15 +1096,16 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
struct cpc_register_resource *delivered_reg, *reference_reg,
*ref_perf_reg, *ctr_wrap_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
- struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
+ struct cppc_pcc_data *pcc_ss_data;
u64 delivered, reference, ref_perf, ctr_wrap_time;
int ret = 0, regs_in_pcc = 0;

- if (!cpc_desc) {
+ if (!cpc_desc || pcc_ss_id < 0) {
pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
return -ENODEV;
}

+ pcc_ss_data = pcc_data[pcc_ss_id];
delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
@@ -1172,11 +1174,12 @@ int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
int ret = 0;

- if (!cpc_desc) {
+ if (!cpc_desc || pcc_ss_id < 0) {
pr_debug("No CPC descriptor for CPU:%d\n", cpu);
return -ENODEV;
}

+ pcc_ss_data = pcc_data[pcc_ss_id];
desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];

/*
@@ -1301,7 +1304,7 @@ unsigned int cppc_get_transition_latency(int cpu_num)
struct cpc_desc *cpc_desc;
struct cpc_register_resource *desired_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
- struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
+ struct cppc_pcc_data *pcc_ss_data;

cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
if (!cpc_desc)
@@ -1311,6 +1314,10 @@ unsigned int cppc_get_transition_latency(int cpu_num)
if (!CPC_IN_PCC(desired_reg))
return CPUFREQ_ETERNAL;

+ if (pcc_ss_id < 0)
+ return CPUFREQ_ETERNAL;
+
+ pcc_ss_data = pcc_data[pcc_ss_id];
if (pcc_ss_data->pcc_mpar)
latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);

--
2.1.4
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