From: Takashi Iwai <tiwai@xxxxxxx> commit c9ce148ea753bef66686460fa3cec6641cdfbb9f upstream. snd_seq_client_use_ptr() is supposed to return the snd_seq_client object for the given client ID, and it tries to handle the module auto-loading when no matching object is found. Although the module handling is performed only conditionally with "!in_interrupt()", this condition may be fragile, e.g. when the code is called from the ALSA timer callback where the spinlock is temporarily disabled while the irq is disabled. Then his doesn't fit well and spews the error about sleep from invalid context, as complained recently by syzbot. Also, in general, handling the module-loading at each time if no matching object is found is really an overkill. It can be still useful when performed at the top-level ioctl or proc reads, but it shouldn't be done at event delivery at all. For addressing the issues above, this patch disables the module handling in snd_seq_client_use_ptr() in normal cases like event deliveries, but allow only in limited and safe situations. A new function client_load_and_use_ptr() is used for the cases where the module loading can be done safely, instead. Reported-by: syzbot+4cb9fad083898f54c517@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://lore.kernel.org/67c272e5.050a0220.dc10f.0159.GAE@xxxxxxxxxx Cc: <stable@xxxxxxxxxxxxxxx> Link: https://patch.msgid.link/20250301114530.8975-1-tiwai@xxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/core/seq/seq_clientmgr.c | 46 ++++++++++++++++++++++++++--------------- 1 file changed, 30 insertions(+), 16 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -106,7 +106,7 @@ static struct snd_seq_client *clientptr( return clienttab[clientid]; } -struct snd_seq_client *snd_seq_client_use_ptr(int clientid) +static struct snd_seq_client *client_use_ptr(int clientid, bool load_module) { unsigned long flags; struct snd_seq_client *client; @@ -126,7 +126,7 @@ struct snd_seq_client *snd_seq_client_us } spin_unlock_irqrestore(&clients_lock, flags); #ifdef CONFIG_MODULES - if (!in_interrupt()) { + if (load_module) { static DECLARE_BITMAP(client_requested, SNDRV_SEQ_GLOBAL_CLIENTS); static DECLARE_BITMAP(card_requested, SNDRV_CARDS); @@ -168,6 +168,20 @@ struct snd_seq_client *snd_seq_client_us return client; } +/* get snd_seq_client object for the given id quickly */ +struct snd_seq_client *snd_seq_client_use_ptr(int clientid) +{ + return client_use_ptr(clientid, false); +} + +/* get snd_seq_client object for the given id; + * if not found, retry after loading the modules + */ +static struct snd_seq_client *client_load_and_use_ptr(int clientid) +{ + return client_use_ptr(clientid, IS_ENABLED(CONFIG_MODULES)); +} + /* Take refcount and perform ioctl_mutex lock on the given client; * used only for OSS sequencer * Unlock via snd_seq_client_ioctl_unlock() below @@ -176,7 +190,7 @@ bool snd_seq_client_ioctl_lock(int clien { struct snd_seq_client *client; - client = snd_seq_client_use_ptr(clientid); + client = client_load_and_use_ptr(clientid); if (!client) return false; mutex_lock(&client->ioctl_mutex); @@ -1200,7 +1214,7 @@ static int snd_seq_ioctl_running_mode(st int err = 0; /* requested client number */ - cptr = snd_seq_client_use_ptr(info->client); + cptr = client_load_and_use_ptr(info->client); if (cptr == NULL) return -ENOENT; /* don't change !!! */ @@ -1262,7 +1276,7 @@ static int snd_seq_ioctl_get_client_info struct snd_seq_client *cptr; /* requested client number */ - cptr = snd_seq_client_use_ptr(client_info->client); + cptr = client_load_and_use_ptr(client_info->client); if (cptr == NULL) return -ENOENT; /* don't change !!! */ @@ -1397,7 +1411,7 @@ static int snd_seq_ioctl_get_port_info(s struct snd_seq_client *cptr; struct snd_seq_client_port *port; - cptr = snd_seq_client_use_ptr(info->addr.client); + cptr = client_load_and_use_ptr(info->addr.client); if (cptr == NULL) return -ENXIO; @@ -1501,10 +1515,10 @@ static int snd_seq_ioctl_subscribe_port( struct snd_seq_client *receiver = NULL, *sender = NULL; struct snd_seq_client_port *sport = NULL, *dport = NULL; - receiver = snd_seq_client_use_ptr(subs->dest.client); + receiver = client_load_and_use_ptr(subs->dest.client); if (!receiver) goto __end; - sender = snd_seq_client_use_ptr(subs->sender.client); + sender = client_load_and_use_ptr(subs->sender.client); if (!sender) goto __end; sport = snd_seq_port_use_ptr(sender, subs->sender.port); @@ -1865,7 +1879,7 @@ static int snd_seq_ioctl_get_client_pool struct snd_seq_client_pool *info = arg; struct snd_seq_client *cptr; - cptr = snd_seq_client_use_ptr(info->client); + cptr = client_load_and_use_ptr(info->client); if (cptr == NULL) return -ENOENT; memset(info, 0, sizeof(*info)); @@ -1969,7 +1983,7 @@ static int snd_seq_ioctl_get_subscriptio struct snd_seq_client_port *sport = NULL; result = -EINVAL; - sender = snd_seq_client_use_ptr(subs->sender.client); + sender = client_load_and_use_ptr(subs->sender.client); if (!sender) goto __end; sport = snd_seq_port_use_ptr(sender, subs->sender.port); @@ -2000,7 +2014,7 @@ static int snd_seq_ioctl_query_subs(stru struct list_head *p; int i; - cptr = snd_seq_client_use_ptr(subs->root.client); + cptr = client_load_and_use_ptr(subs->root.client); if (!cptr) goto __end; port = snd_seq_port_use_ptr(cptr, subs->root.port); @@ -2067,7 +2081,7 @@ static int snd_seq_ioctl_query_next_clie if (info->client < 0) info->client = 0; for (; info->client < SNDRV_SEQ_MAX_CLIENTS; info->client++) { - cptr = snd_seq_client_use_ptr(info->client); + cptr = client_load_and_use_ptr(info->client); if (cptr) break; /* found */ } @@ -2090,7 +2104,7 @@ static int snd_seq_ioctl_query_next_port struct snd_seq_client *cptr; struct snd_seq_client_port *port = NULL; - cptr = snd_seq_client_use_ptr(info->addr.client); + cptr = client_load_and_use_ptr(info->addr.client); if (cptr == NULL) return -ENXIO; @@ -2187,7 +2201,7 @@ static int snd_seq_ioctl_client_ump_info size = sizeof(struct snd_ump_endpoint_info); else size = sizeof(struct snd_ump_block_info); - cptr = snd_seq_client_use_ptr(client); + cptr = client_load_and_use_ptr(client); if (!cptr) return -ENOENT; @@ -2459,7 +2473,7 @@ int snd_seq_kernel_client_enqueue(int cl if (check_event_type_and_length(ev)) return -EINVAL; - cptr = snd_seq_client_use_ptr(client); + cptr = client_load_and_use_ptr(client); if (cptr == NULL) return -EINVAL; @@ -2686,7 +2700,7 @@ void snd_seq_info_clients_read(struct sn /* list the client table */ for (c = 0; c < SNDRV_SEQ_MAX_CLIENTS; c++) { - client = snd_seq_client_use_ptr(c); + client = client_load_and_use_ptr(c); if (client == NULL) continue; if (client->type == NO_CLIENT) { Patches currently in stable-queue which might be from tiwai@xxxxxxx are queue-6.6/alsa-seq-avoid-module-auto-load-handling-at-event-delivery.patch queue-6.6/alsa-hda-realtek-update-alc222-depop-optimize.patch queue-6.6/alsa-hda-realtek-add-supported-mic-mute-led-for-lenovo-platform.patch queue-6.6/alsa-hda-intel-add-dell-alc3271-to-power_save-denylist.patch
