From e4d3386b74fba8e01280484b67ee481ece00201e Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Sun, 17 May 2026 18:51:20 +0200 Subject: [PATCH] ALSA: pcm: Don't setup bogus iov_iter for silencing At transition to the iov_iter for PCM data transfer, we blindly applied the iov_iter setup also for silencing (i.e. data = NULL), and it leads to a calculation of bogus iov_iter. Fortunately this didn't cause troubles on most of architectures but it goes wrong on RISC-V now, causing a NULL dereference. Handle the NULL data case to treat the silencing in interleaved_copy() for addressing the bug above. noninterleaved_copy() has already the NULL data handling, so it doesn't need changes. Reported-by: Jiakai Xu Closes: https://lore.kernel.org/20260515051516.3103036-1-xujiakai24@mails.ucas.ac.cn Fixes: cf393babb37a ("ALSA: pcm: Add copy ops with iov_iter") Cc: Link: https://patch.msgid.link/20260517165121.31399-1-tiwai@suse.de Signed-off-by: Takashi Iwai --- sound/core/pcm_lib.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 09c421cd9319..fe597f7d522d 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -2138,6 +2138,9 @@ static int interleaved_copy(struct snd_pcm_substream *substream, off = frames_to_bytes(runtime, off); frames = frames_to_bytes(runtime, frames); + if (!data) + return fill_silence(substream, 0, hwoff, NULL, frames); + return do_transfer(substream, 0, hwoff, data + off, frames, transfer, in_kernel); }