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ALSA: seq: Remove arbitrary prioq insertion limit

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The sequencer priority queue insertion path uses a hardcoded traversal
limit of 10000 entries.  The value is intended to catch a corrupted list,
but it also becomes a real limit for valid queues.

The event pool limit is per client, while a sequencer queue can be shared
by multiple clients.  A queue can therefore legitimately contain more than
10000 events.  In that case, inserting an event that has to be placed past
the arbitrary limit fails with -EINVAL.

Use the queue's own cell count as the traversal bound instead.  This keeps
the protection against inconsistent list accounting or cyclic lists without
rejecting valid large queues.

Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260525-alsa-seq-prioq-limit-v1-1-16c348df5ff7@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Cássio Gabriel 2026-05-25 11:16:09 -03:00 committed by Takashi Iwai
parent 5d1d092b8d
commit 3fcc84f1f8
1 changed files with 8 additions and 6 deletions
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14
sound/core/seq/seq_prioq.c
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@ -132,7 +132,7 @@ int snd_seq_prioq_cell_in(struct snd_seq_prioq * f,
struct snd_seq_event_cell * cell)
{
struct snd_seq_event_cell *cur, *prev;
int count;
int remaining;
int prior;
if (snd_BUG_ON(!f || !cell))
@ -162,10 +162,16 @@ int snd_seq_prioq_cell_in(struct snd_seq_prioq * f,
prev = NULL; /* previous cell */
cur = f->head; /* cursor */
count = 10000; /* FIXME: enough big, isn't it? */
remaining = f->cells;
while (cur != NULL) {
/* compare timestamps */
int rel = compare_timestamp_rel(&cell->event, &cur->event);
if (remaining-- <= 0) {
pr_err("ALSA: seq: inconsistent prioq cell count\n");
return -EINVAL;
}
if (rel < 0)
/* new cell has earlier schedule time, */
break;
@ -176,10 +182,6 @@ int snd_seq_prioq_cell_in(struct snd_seq_prioq * f,
/* move cursor to next cell */
prev = cur;
cur = cur->next;
if (! --count) {
pr_err("ALSA: seq: cannot find a pointer.. infinite loop?\n");
return -EINVAL;
}
}
/* insert it before cursor */