Re: [PATCH -next v2] ALSA: pcm: fix undefined behavior in bit shift for SNDRV_PCM_RATE_KNOT

[Takashi Iwai]

On Mon, 21 Nov 2022 12:00:44 +0100,
Baisong Zhong wrote:
> 
> Shifting signed 32-bit value by 31 bits is undefined, so changing
> significant bit to unsigned. The UBSAN warning calltrace like below:
> 
> UBSAN: shift-out-of-bounds in sound/core/pcm_native.c:2676:21
> left shift of 1 by 31 places cannot be represented in type 'int'
> ...
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x8d/0xcf
>  ubsan_epilogue+0xa/0x44
>  __ubsan_handle_shift_out_of_bounds+0x1e7/0x208
>  snd_pcm_open_substream+0x9f0/0xa90
>  snd_pcm_oss_open.part.26+0x313/0x670
>  snd_pcm_oss_open+0x30/0x40
>  soundcore_open+0x18b/0x2e0
>  chrdev_open+0xe2/0x270
>  do_dentry_open+0x2f7/0x620
>  path_openat+0xd66/0xe70
>  do_filp_open+0xe3/0x170
>  do_sys_openat2+0x357/0x4a0
>  do_sys_open+0x87/0xd0
>  do_syscall_64+0x34/0x80
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Baisong Zhong <zhongbaisong@xxxxxxxxxx>
> ---
> v2: update all SNDRV_PCM_RATE_* to 1U to keep consistent

Thanks, applied now.


Takashi