6.6-stable review patch. If anyone has any objections, please let me know.
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From: Josh Poimboeuf jpoimboe@kernel.org
[ 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 lkp@intel.com Signed-off-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Ingo Molnar mingo@kernel.org Acked-by: Mark Brown broonie@kernel.org Cc: Liam Girdwood lgirdwood@gmail.com Cc: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/r/2023abcddf3f524ba478d64339996f25dc4097d2.174285284... Closes: https://lore.kernel.org/oe-kbuild-all/202503182350.52KeHGD4-lkp@intel.com/ Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/regulator/rk808-regulator.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
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;