From: Chao Qin <chao.qin@intel.com>
Date: Tue, 20 Sep 2022 06:08:26 +0000 (+0800)
Subject: powercap: intel_rapl: fix UBSAN shift-out-of-bounds issue
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=139bbbd01114433b80fe59f5e1330615aadf9752;p=linux.git

powercap: intel_rapl: fix UBSAN shift-out-of-bounds issue

[ 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>
---

diff --git a/drivers/powercap/intel_rapl_common.c b/drivers/powercap/intel_rapl_common.c
index c87d4687aa671..9dfc053878fda 100644
--- a/drivers/powercap/intel_rapl_common.c
+++ b/drivers/powercap/intel_rapl_common.c
@@ -938,6 +938,9 @@ 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);