This is a note to let you know that I've just added the patch titled ALSA: memalloc.h - fix wrong truncation of dma_addr_t to the 3.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-memalloc.h-fix-wrong-truncation-of-dma_addr_t.patch and it can be found in the queue-3.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 932e9dec380c67ec15ac3eb073bb55797d8b4801 Mon Sep 17 00:00:00 2001 From: Stefano Panella <stefano.panella@xxxxxxxxxx> Date: Tue, 10 Dec 2013 14:20:28 +0000 Subject: ALSA: memalloc.h - fix wrong truncation of dma_addr_t From: Stefano Panella <stefano.panella@xxxxxxxxxx> commit 932e9dec380c67ec15ac3eb073bb55797d8b4801 upstream. When running a 32bit kernel the hda_intel driver is still reporting a 64bit dma_mask if the HW supports it. >From sound/pci/hda/hda_intel.c: /* allow 64bit DMA address if supported by H/W */ if ((gcap & ICH6_GCAP_64OK) && !pci_set_dma_mask(pci, DMA_BIT_MASK(64))) pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(64)); else { pci_set_dma_mask(pci, DMA_BIT_MASK(32)); pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(32)); } which means when there is a call to dma_alloc_coherent from snd_malloc_dev_pages a machine address bigger than 32bit can be returned. This can be true in particular if running the 32bit kernel as a pv dom0 under the Xen Hypervisor or PAE on bare metal. The problem is that when calling setup_bdle to program the BLE the dma_addr_t returned from the dma_alloc_coherent is wrongly truncated from snd_sgbuf_get_addr if running a 32bit kernel: static inline dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset) { struct snd_sg_buf *sgbuf = dmab->private_data; dma_addr_t addr = sgbuf->table[offset >> PAGE_SHIFT].addr; addr &= PAGE_MASK; return addr + offset % PAGE_SIZE; } where PAGE_MASK in a 32bit kernel is zeroing the upper 32bit af addr. Without this patch the HW will fetch the 32bit truncated address, which is not the one obtained from dma_alloc_coherent and will result to a non working audio but can corrupt host memory at a random location. The current patch apply to v3.13-rc3-74-g6c843f5 Signed-off-by: Stefano Panella <stefano.panella@xxxxxxxxxx> Reviewed-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/sound/memalloc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/sound/memalloc.h +++ b/include/sound/memalloc.h @@ -103,7 +103,7 @@ static inline dma_addr_t snd_sgbuf_get_a { struct snd_sg_buf *sgbuf = dmab->private_data; dma_addr_t addr = sgbuf->table[offset >> PAGE_SHIFT].addr; - addr &= PAGE_MASK; + addr &= ~((dma_addr_t)PAGE_SIZE - 1); return addr + offset % PAGE_SIZE; } Patches currently in stable-queue which might be from stefano.panella@xxxxxxxxxx are queue-3.12/alsa-memalloc.h-fix-wrong-truncation-of-dma_addr_t.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html