This is a note to let you know that I've just added the patch titled
power: supply: da9150-fg: fix potential overflow
to the 6.13-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:
power-supply-da9150-fg-fix-potential-overflow.patch
and it can be found in the queue-6.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9929272b81698ab763bb0061c9241409f256f261
Author: Andrey Vatoropin <a.vatoropin@xxxxxxx>
Date: Thu Jan 30 09:00:34 2025 +0000
power: supply: da9150-fg: fix potential overflow
[ Upstream commit 3fb3cb4350befc4f901c54e0cb4a2a47b1302e08 ]
Size of variable sd_gain equals four bytes - DA9150_QIF_SD_GAIN_SIZE.
Size of variable shunt_val equals two bytes - DA9150_QIF_SHUNT_VAL_SIZE.
The expression sd_gain * shunt_val is currently being evaluated using
32-bit arithmetic. So during the multiplication an overflow may occur.
As the value of type 'u64' is used as storage for the eventual result, put
ULL variable at the first position of each expression in order to give the
compiler complete information about the proper arithmetic to use. According
to C99 the guaranteed width for a variable of type 'unsigned long long' >=
64 bits.
Remove the explicit cast to u64 as it is meaningless.
Just for the sake of consistency, perform the similar trick with another
expression concerning 'iavg'.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: a419b4fd9138 ("power: Add support for DA9150 Fuel-Gauge")
Signed-off-by: Andrey Vatoropin <a.vatoropin@xxxxxxx>
Link: https://lore.kernel.org/r/20250130090030.53422-1-a.vatoropin@xxxxxxx
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/power/supply/da9150-fg.c b/drivers/power/supply/da9150-fg.c
index 652c1f213af1c..4f28ef1bba1a3 100644
--- a/drivers/power/supply/da9150-fg.c
+++ b/drivers/power/supply/da9150-fg.c
@@ -247,9 +247,9 @@ static int da9150_fg_current_avg(struct da9150_fg *fg,
DA9150_QIF_SD_GAIN_SIZE);
da9150_fg_read_sync_end(fg);
- div = (u64) (sd_gain * shunt_val * 65536ULL);
+ div = 65536ULL * sd_gain * shunt_val;
do_div(div, 1000000);
- res = (u64) (iavg * 1000000ULL);
+ res = 1000000ULL * iavg;
do_div(res, div);
val->intval = (int) res;
