On 25/07/24 10:11, Takashi Iwai wrote:
On Thu, 25 Jul 2024 18:08:21 +0200, Gustavo A. R. Silva wrote:
On 25/07/24 09:56, Takashi Sakamoto wrote:
In a commit 1d717123bb1a ("ALSA: firewire-lib: Avoid -Wflex-array-member-not-at-end warning"), DEFINE_FLEX() macro was used to handle variable length of array for header field in struct fw_iso_packet structure. The usage of macro has a side effect that the designated initializer assigns the count of array to the given field. Therefore CIP_HEADER_QUADLETS (=2) is assigned to struct fw_iso_packet.header, while the original designated initializer assigns zero to all fields.
With CIP_NO_HEADER flag, the change causes invalid length of header in isochronous packet for 1394 OHCI IT context. This bug affects all of devices supported by ALSA fireface driver; RME Fireface 400, 800, UCX, UFX, and 802.
This commit fixes the bug by replacing it with the alternative version of macro which corresponds no initializer.
This change is incomplete. The patch I mention here[1] should also be applied.
Yes, but this can be fixed by another patch, right?
Yes, but why have two separate patches when the root cause can be addressed by a single one, which will prevent other potential issues from occurring?
The main issue in this case is the __counted_by() annotation. The DEFINE_FLEX() bug was a consequence.
-- Gustavo
At least the regression introduced by the given commit can be fixed by that. The other fix can go through Sakamoto-san's firewire tree individually.
thanks,
Takashi
BTW, there is one more line that should probably be changed in `struct fw_iso_packet` to avoid further confusions:
u16 payload_length; /* Length of indirect payload */
u16 payload_length; /* Size of indirect payload */Thanks
Gustavo
[1] https://lore.kernel.org/linux-sound/dabb394e-6c85-45a0-bc06-7a45262a9a8c@emb...
Cc: stable@vger.kernel.org Fixes: 1d717123bb1a ("ALSA: firewire-lib: Avoid -Wflex-array-member-not-at-end warning") Reported-by: Edmund Raile edmund.raile@proton.me Closes: https://lore.kernel.org/r/rrufondjeynlkx2lniot26ablsltnynfaq2gnqvbiso7ds32il... Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
sound/firewire/amdtp-stream.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c index d35d0a420ee0..1a163bbcabd7 100644 --- a/sound/firewire/amdtp-stream.c +++ b/sound/firewire/amdtp-stream.c @@ -1180,8 +1180,7 @@ static void process_rx_packets(struct fw_iso_context *context, u32 tstamp, size_ (void)fw_card_read_cycle_time(fw_parent_device(s->unit)->card, &curr_cycle_time); for (i = 0; i < packets; ++i) {
DEFINE_FLEX(struct fw_iso_packet, template, header,header_length, CIP_HEADER_QUADLETS);
DEFINE_RAW_FLEX(struct fw_iso_packet, template, header, CIP_HEADER_QUADLETS); bool sched_irq = false; build_it_pkt_header(s, desc->cycle, template,pkt_header_length,