5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Josh Poimboeuf jpoimboe@kernel.org
[ Upstream commit e63d465f59011dede0a0f1d21718b59a64c3ff5c ]
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 lkp@intel.com Signed-off-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Mauro Carvalho Chehab mchehab@kernel.org Cc: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/r/bd1d504d930ae3f073b1e071bcf62cae7708773c.174285284... Closes: https://lore.kernel.org/r/202503210602.fvH5DO1i-lkp@intel.com/ Signed-off-by: Sasha Levin sashal@kernel.org --- 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 02cb48223dc67..a28cbbd9e475c 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