Re: [PATCH v2 0/4] ALSA: compress: fix buffer handling and state validation

[Takashi Iwai <tiwai@suse.de>]

On Mon, 19 Oct 2026 16:45:29 +0200,
Peter Ujfalusi wrote:
> 
> Hi,
> 
> Changes since v1:
> - patch 1: do not free the old buffer in snd_compr_allocate_buffer().
>   SET_PARAMS can only be repeated in OPEN state after ops->set_params()
>   has failed, so release the framework-owned buffer on that error path
>   instead. The buffer is allocated once per successful SET_PARAMS and is
>   never replaced (Vinod, Takashi)
> - patch 2: reworded the commit message: the buffer is set up once and the
>   next_track path does not re-allocate it. The geometry check is kept
>   because ops->set_params() would otherwise receive buffer parameters
>   that do not match the buffer in use. tinycompress always passes the
>   open-time fragment_size/fragments on next_track, so existing users are
>   not affected (Vinod)
> - patches 3 and 4: added Acked-by from Vinod
> 
> The compress offload core has several edge cases in buffer management
> and state validation.
> 
> A SET_PARAMS that the driver rejects leaves the framework-owned buffer
> allocated while the stream stays in the OPEN state, so a following
> SET_PARAMS overwrites the pointer and leaks the buffer. During gapless
> playback, SET_PARAMS can also change the buffer geometry while the byte
> counters still refer to the current buffer. Separately, SET_METADATA can
> reach the driver before SET_PARAMS, and the origin_seqno task lookup can
> restart a task that is still ACTIVE.
> 
> Address these cases by:
> - releasing the framework-owned buffer when ops->set_params() fails, so
>   the buffer is allocated once per successful SET_PARAMS;
> - not re-allocating the buffer on the gapless next_track path and
>   rejecting a buffer geometry change there;
> - rejecting SET_METADATA while the stream is OPEN; and
> - allowing origin_seqno to reuse IDLE or FINISHED tasks, but not ACTIVE
>   ones.
> 
> Regards,
> Peter
> ---
> Peter Ujfalusi (4):
>   ALSA: compress: fix buffer leak on failed SET_PARAMS
>   ALSA: compress: reject buffer geometry change on gapless next_track
>   ALSA: compress: add missing OPEN-state gate to SET_METADATA
>   ALSA: compress: reject restarting an ACTIVE task via origin_seqno

Applied all four patches now.  Thanks.


Takashi