On Tue, Aug 16, 2016 at 11:22:01PM +0900, Seung-Woo Kim wrote: > From pwm_samsung_calc_tin(), there is routine to find the lowest > divider possible to generate lower frequency than requested one. > But it is always possible to generate requested frequency with > large enough modulation bits except s3c24xx, so this patch fixes > to use lowest div for the case. This patch removes following UBSAN > warning: > > UBSAN: Undefined behaviour in drivers/pwm/pwm-samsung.c:197:13 > shift exponent 32 is too large for 32-bit type 'long unsigned int' > [...] > [<c0670248>] (ubsan_epilogue) from [<c06707b4>] (__ubsan_handle_shift_out_of_bounds+0xd8/0x120) > [<c06707b4>] (__ubsan_handle_shift_out_of_bounds) from [<c0694b28>] (pwm_samsung_config+0x508/0x6a4) > [<c0694b28>] (pwm_samsung_config) from [<c069286c>] (pwm_apply_state+0x174/0x40c) > [<c069286c>] (pwm_apply_state) from [<c0b2e070>] (pwm_fan_probe+0xc8/0x488) > [<c0b2e070>] (pwm_fan_probe) from [<c07ba8b0>] (platform_drv_probe+0x70/0x150) > [...] > > Cc: Tomasz Figa <tomasz.figa@xxxxxxxxx> > Signed-off-by: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx> > --- > Changes from v1 > * Remove too complex condition, instead, just checking simple variant->bits as Krzysztof's suggestion > * Add comment from Tomasz > > The UBSAN warning from ARM is reported with the patch in following link: > https://patchwork.kernel.org/patch/9189575/ > --- > drivers/pwm/pwm-samsung.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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