From: Josh Poimboeuf Date: Mon, 24 Mar 2025 21:56:10 +0000 (-0700) Subject: objtool, regulator: rk808: Remove potential undefined behavior in rk806_set_mode_dcdc() X-Git-Tag: v6.6.89~60 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11c16b644934675fcae949589b940a7169894c1a;p=thirdparty%2Fkernel%2Fstable.git objtool, regulator: rk808: Remove potential undefined behavior in rk806_set_mode_dcdc() [ Upstream commit 29c578c848402a34e8c8e115bf66cb6008b77062 ] If 'ctr_bit' is negative, the shift counts become negative, causing a shift of bounds and undefined behavior. Presumably that's not possible in normal operation, but the code generation isn't optimal. And undefined behavior should be avoided regardless. Improve code generation and remove the undefined behavior by converting the signed variables to unsigned. Fixes the following warning with an UBSAN kernel: vmlinux.o: warning: objtool: rk806_set_mode_dcdc() falls through to next function rk806_get_mode_dcdc() vmlinux.o: warning: objtool: .text.rk806_set_mode_dcdc: unexpected end of section Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Acked-by: Mark Brown Cc: Liam Girdwood Cc: Linus Torvalds Link: https://lore.kernel.org/r/2023abcddf3f524ba478d64339996f25dc4097d2.1742852847.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/oe-kbuild-all/202503182350.52KeHGD4-lkp@intel.com/ Signed-off-by: Sasha Levin --- diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c index 374d80dc6d17a..bec22a001a5dd 100644 --- a/drivers/regulator/rk808-regulator.c +++ b/drivers/regulator/rk808-regulator.c @@ -267,8 +267,8 @@ static const unsigned int rk817_buck1_4_ramp_table[] = { static int rk806_set_mode_dcdc(struct regulator_dev *rdev, unsigned int mode) { - int rid = rdev_get_id(rdev); - int ctr_bit, reg; + unsigned int rid = rdev_get_id(rdev); + unsigned int ctr_bit, reg; reg = RK806_POWER_FPWM_EN0 + rid / 8; ctr_bit = rid % 8;