[PATCH AUTOSEL 5.4 3/6] powercap: intel_rapl: fix UBSAN shift-out-of-bounds issue

[PATCH AUTOSEL 5.4 3/6] powercap: intel_rapl: fix UBSAN shift-out-of-bounds issue

[Sasha Levin]

From: Chao Qin <chao.qin@intel.com>

[ Upstream commit 2d93540014387d1c73b9ccc4d7895320df66d01b ]

When value < time_unit, the parameter of ilog2() will be zero and
the return value is -1. u64(-1) is too large for shift exponent
and then will trigger shift-out-of-bounds:

shift exponent 18446744073709551615 is too large for 32-bit type 'int'
Call Trace:
 rapl_compute_time_window_core
 rapl_write_data_raw
 set_time_window
 store_constraint_time_window_us

Signed-off-by: Chao Qin <chao.qin@intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/powercap/intel_rapl_common.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/powercap/intel_rapl_common.c b/drivers/powercap/intel_rapl_common.c
index 925b0004a0ed..d5a505f32260 100644
--- a/drivers/powercap/intel_rapl_common.c
+++ b/drivers/powercap/intel_rapl_common.c
@@ -885,6 +885,9 @@ static u64 rapl_compute_time_window_core(struct rapl_package *rp, u64 value,
 		y = value & 0x1f;
 		value = (1 << y) * (4 + f) * rp->time_unit / 4;
 	} else {
+		if (value < rp->time_unit)
+			return 0;
+
 		do_div(value, rp->time_unit);
 		y = ilog2(value);
 		f = div64_u64(4 * (value - (1 << y)), 1 << y);
-- 
2.35.1

[PATCH AUTOSEL 5.4 4/6] thermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash

[Sasha Levin]

From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

[ Upstream commit 68b99e94a4a2db6ba9b31fe0485e057b9354a640 ]

When CPU 0 is offline and intel_powerclamp is used to inject
idle, it generates kernel BUG:

BUG: using smp_processor_id() in preemptible [00000000] code: bash/15687
caller is debug_smp_processor_id+0x17/0x20
CPU: 4 PID: 15687 Comm: bash Not tainted 5.19.0-rc7+ #57
Call Trace:
<TASK>
dump_stack_lvl+0x49/0x63
dump_stack+0x10/0x16
check_preemption_disabled+0xdd/0xe0
debug_smp_processor_id+0x17/0x20
powerclamp_set_cur_state+0x7f/0xf9 [intel_powerclamp]
...
...

Here CPU 0 is the control CPU by default and changed to the current CPU,
if CPU 0 offlined. This check has to be performed under cpus_read_lock(),
hence the above warning.

Use get_cpu() instead of smp_processor_id() to avoid this BUG.

Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/thermal/intel/intel_powerclamp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c
index 53216dcbe173..5e4f32733caf 100644
--- a/drivers/thermal/intel/intel_powerclamp.c
+++ b/drivers/thermal/intel/intel_powerclamp.c
@@ -535,8 +535,10 @@ static int start_power_clamp(void)
 
 	/* prefer BSP */
 	control_cpu = 0;
-	if (!cpu_online(control_cpu))
-		control_cpu = smp_processor_id();
+	if (!cpu_online(control_cpu)) {
+		control_cpu = get_cpu();
+		put_cpu();
+	}
 
 	clamping = true;
 	schedule_delayed_work(&poll_pkg_cstate_work, 0);
-- 
2.35.1