Static analysis says "size" is a number 0-63. So we really want to be doing the shift as a u64 and not a int type. Presumably "size" is never actually more than 31 otherwise the shift wrap would have been detected in testing. The "mask" is a u32 so we only care about the bottom 32 bits which also implies that "size" is less than 32.
This code pre-dates git. I haven't tested this change, it's to fix a static analysis warning. I can't think that shift wrapping is the correct behavior so presumably this change is harmless but it definitely changes how the code works when size is larger than 32. Signed-off-by: Dan Carpenter <[email protected]> diff --git a/sound/pci/emu10k1/io.c b/sound/pci/emu10k1/io.c index 706b4f0..fd204f3 100644 --- a/sound/pci/emu10k1/io.c +++ b/sound/pci/emu10k1/io.c @@ -46,7 +46,7 @@ unsigned int snd_emu10k1_ptr_read(struct snd_emu10k1 * emu, unsigned int reg, un size = (reg >> 24) & 0x3f; offset = (reg >> 16) & 0x1f; - mask = ((1 << size) - 1) << offset; + mask = ((1ULL << size) - 1) << offset; spin_lock_irqsave(&emu->emu_lock, flags); outl(regptr, emu->port + PTR); @@ -81,7 +81,7 @@ void snd_emu10k1_ptr_write(struct snd_emu10k1 *emu, unsigned int reg, unsigned i size = (reg >> 24) & 0x3f; offset = (reg >> 16) & 0x1f; - mask = ((1 << size) - 1) << offset; + mask = ((1ULL << size) - 1) << offset; data = (data << offset) & mask; spin_lock_irqsave(&emu->emu_lock, flags);
