6.6-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit d2913a07d9037fe7aed4b7e680684163eaed6bc4 upstream.
A driver might allow the mmap access before initializing its runtime->dma_area properly. Add a proper NULL check before passing to virt_to_page() for avoiding a panic.
Reported-by: syzbot+4bf62a7b1d0f4fdb7ae2@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20241120141104.7060-1-tiwai@suse.de Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- sound/core/pcm_native.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -3794,9 +3794,11 @@ static vm_fault_t snd_pcm_mmap_data_faul return VM_FAULT_SIGBUS; if (substream->ops->page) page = substream->ops->page(substream, offset); - else if (!snd_pcm_get_dma_buf(substream)) + else if (!snd_pcm_get_dma_buf(substream)) { + if (WARN_ON_ONCE(!runtime->dma_area)) + return VM_FAULT_SIGBUS; page = virt_to_page(runtime->dma_area + offset); - else + } else page = snd_sgbuf_get_page(snd_pcm_get_dma_buf(substream), offset); if (!page) return VM_FAULT_SIGBUS;