From e63d465f59011dede0a0f1d21718b59a64c3ff5c Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 24 Mar 2025 14:56:06 -0700 Subject: [PATCH] objtool, media: dib8000: Prevent divide-by-zero in dib8000_set_dds() If dib8000_set_dds()'s call to dib8000_read32() returns zero, the result is a divide-by-zero. Prevent that from happening. Fixes the following warning with an UBSAN kernel: drivers/media/dvb-frontends/dib8000.o: warning: objtool: dib8000_tune() falls through to next function dib8096p_cfg_DibRx() Fixes: 173a64cb3fcf ("[media] dib8000: enhancement") Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Mauro Carvalho Chehab Cc: Linus Torvalds Link: https://lore.kernel.org/r/bd1d504d930ae3f073b1e071bcf62cae7708773c.1742852847.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/r/202503210602.fvH5DO1i-lkp@intel.com/ --- drivers/media/dvb-frontends/dib8000.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/media/dvb-frontends/dib8000.c b/drivers/media/dvb-frontends/dib8000.c index 2f5165918163..cfe59c3255f7 100644 --- a/drivers/media/dvb-frontends/dib8000.c +++ b/drivers/media/dvb-frontends/dib8000.c @@ -2701,8 +2701,11 @@ static void dib8000_set_dds(struct dib8000_state *state, s32 offset_khz) u8 ratio; if (state->revision == 0x8090) { + u32 internal = dib8000_read32(state, 23) / 1000; + ratio = 4; - unit_khz_dds_val = (1<<26) / (dib8000_read32(state, 23) / 1000); + + unit_khz_dds_val = (1<<26) / (internal ?: 1); if (offset_khz < 0) dds = (1 << 26) - (abs_offset_khz * unit_khz_dds_val); else -- 2.50.1