kernel/linux.git/sound/core/seq/seq_clientmgr.c, branch v6.12.80

ALSA: seq: Improve data consistency at polling

2025-05-29T09:02:27+00:00

[ Upstream commit e3cd33ab17c33bd8f1a9df66ec83a15dd8f7afbb ] snd_seq_poll() calls snd_seq_write_pool_allocated() that reads out a field in client->pool object, while it can be updated concurrently via ioctls, as reported by syzbot. The data race itself is harmless, as it's merely a poll() call, and the state is volatile. OTOH, the read out of poll object info from the caller side is fragile, and we can leave it better in snd_seq_pool_poll_wait() alone. A similar pattern is seen in snd_seq_kernel_client_write_poll(), too, which is called from the OSS sequencer. This patch drops the pool checks from the caller side and add the pool->lock in snd_seq_pool_poll_wait() for better data consistency. Reported-by: syzbot+2d373c9936c00d7e120c@syzkaller.appspotmail.com Closes: https://lore.kernel.org/67c88903.050a0220.15b4b9.0028.GAE@google.com Link: https://patch.msgid.link/20250307084246.29271-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: seq: Fix delivery of UMP events to group ports

2025-05-22T12:29:40+00:00

[ Upstream commit ff7b190aef6cccdb6f14d20c5753081fe6420e0b ] When an event with UMP message is sent to a UMP client, the EP port receives always no matter where the event is sent to, as it's a catch-all port. OTOH, if an event is sent to EP port, and if the event has a certain UMP Group, it should have been delivered to the associated UMP Group port, too, but this was ignored, so far. This patch addresses the behavior. Now a UMP event sent to the Endpoint port will be delivered to the subscribers of the UMP group port the event is associated with. The patch also does a bit of refactoring to simplify the code about __deliver_to_subscribers(). Fixes: 177ccf811df4 ("ALSA: seq: Support MIDI 2.0 UMP Endpoint port") Link: https://patch.msgid.link/20250511134528.6314-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: seq: Avoid module auto-load handling at event delivery

2025-03-13T12:01:52+00:00

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@syzkaller.appspotmail.com Closes: https://lore.kernel.org/67c272e5.050a0220.dc10f.0159.GAE@google.com Cc: Link: https://patch.msgid.link/20250301114530.8975-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: seq: Drop UMP events when no UMP-conversion is set

2025-02-27T12:30:17+00:00

[ Upstream commit e77aa4b2eaa7fb31b2a7a50214ecb946b2a8b0f6 ] When a destination client is a user client in the legacy MIDI mode and it sets the no-UMP-conversion flag, currently the all UMP events are still passed as-is. But this may confuse the user-space, because the event packet size is different from the legacy mode. Since we cannot handle UMP events in user clients unless it's running in the UMP client mode, we should filter out those events instead of accepting blindly. This patch addresses it by slightly adjusting the conditions for UMP event handling at the event delivery time. Fixes: 329ffe11a014 ("ALSA: seq: Allow suppressing UMP conversions") Link: https://lore.kernel.org/b77a2cd6-7b59-4eb0-a8db-22d507d3af5f@gmail.com Link: https://patch.msgid.link/20250217170034.21930-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: seq: Check UMP support for midi_version change

2025-01-09T12:33:48+00:00

commit 8765429279e7d3d68d39ace5f84af2815174bb1e upstream. When the kernel is built without UMP support but a user-space app requires the midi_version > 0, the kernel should return an error. Otherwise user-space assumes as if it were possible to deal, eventually hitting serious errors later. Fixes: 46397622a3fa ("ALSA: seq: Add UMP support") Cc: Link: https://patch.msgid.link/20241231145358.21946-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

[tree-wide] finally take no_llseek out

2024-09-27T15:18:43+00:00

no_llseek had been defined to NULL two years ago, in commit 868941b14441 ("fs: remove no_llseek") To quote that commit, At -rc1 we'll need do a mechanical removal of no_llseek - git grep -l -w no_llseek | grep -v porting.rst | while read i; do sed -i '/\/d' $i done would do it. Unfortunately, that hadn't been done. Linus, could you do that now, so that we could finally put that thing to rest? All instances are of the form .llseek = no_llseek, so it's obviously safe. Signed-off-by: Al Viro Signed-off-by: Linus Torvalds

Merge branch 'topic/seq-filter-cleanup' into for-next

2024-08-19T08:48:46+00:00

Pull ALSA sequencer cleanup. Signed-off-by: Takashi Iwai

ALSA: seq: Drop superfluous filter argument of get_event_dest_client()

2024-08-19T08:48:30+00:00

All callers of get_event_dest_clienter() pass 0 to the filter argument, and it means that the check there is utterly redundant. Drop the superfluous filter argument and its check as a code cleanup. Link: https://patch.msgid.link/20240819084757.11902-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: seq: Skip event type filtering for UMP events

2024-08-19T08:43:58+00:00

UMP events don't use the event type field, hence it's invalid to apply the filter, which may drop the events unexpectedly. Skip the event filtering for UMP events, instead. Fixes: 46397622a3fa ("ALSA: seq: Add UMP support") Cc: Link: https://patch.msgid.link/20240819084156.10286-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: seq: Print MIDI 1.0 specific port in proc output

2024-08-07T09:31:38+00:00

When a sequencer port assigned to a UMP Group that is specific to MIDI 1.0 among MIDI 2.0 client, mark it explicitly in the proc output, so that user can see it easily. This is an exceptional case where the message isn't converted to MIDI 1.0 even if the client is running in MIDI 2.0 mode. Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20240807092303.1935-6-tiwai@suse.de