Messages in this thread | | | From | <> | Subject | RE: [PATCH] swiotlb: add overflow checks to swiotlb_bounce | Date | Thu, 8 Jul 2021 09:59:56 +0900 |
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> This is a follow-up on 5f89468e2f06 ("swiotlb: manipulate orig_addr when > tlb_addr has offset") which fixed unaligned dma mappings, making sure the > following overflows are caught: > > - offset of the start of the slot within the device bigger than requested > address' offset, in other words if the base address given in > swiotlb_tbl_map_single to create the mapping (orig_addr) was after the > requested address for the sync (tlb_offset) in the same block: > > |------------------------------------------| block > <----------------------------> mapped part of the block > ^ > orig_addr > ^ > invalid tlb_addr for sync > > - if the resulting offset was bigger than the allocation size this one > could happen if the mapping was not until the end. e.g. > > |------------------------------------------| block > <---------------------> mapped part of the block > ^ ^ > orig_addr invalid tlb_addr > > Both should never happen so print a warning and bail out without trying to > adjust the sizes/offsets: the first one could try to sync from orig_addr > to whatever is left of the requested size, but the later really has > nothing to sync there... > > Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > Cc: Bumyong Lee <bumyong.lee@samsung.com>
Reviewed-by: Bumyong Lee <bumyong.lee@samsung.com
> Cc: Chanho Park <chanho61.park@samsung.com> > Cc: Christoph Hellwig <hch@lst.de> > --- > > Hi Konrad, > > here's the follow up for the swiotlb/caamjr regression I had promissed. > It doesn't really change anything, and I confirmed I don't hit either of > the warnings on our board, but it's probably best to have as either could > really happen. > > > kernel/dma/swiotlb.c | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index > e50df8d8f87e..23f8d0b168c5 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -354,13 +354,27 @@ static void swiotlb_bounce(struct device *dev, > phys_addr_t tlb_addr, size_t size > size_t alloc_size = mem->slots[index].alloc_size; > unsigned long pfn = PFN_DOWN(orig_addr); > unsigned char *vaddr = phys_to_virt(tlb_addr); > - unsigned int tlb_offset; > + unsigned int tlb_offset, orig_addr_offset; > > if (orig_addr == INVALID_PHYS_ADDR) > return; > > - tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) - > - swiotlb_align_offset(dev, orig_addr); > + tlb_offset = tlb_addr & (IO_TLB_SIZE - 1); > + orig_addr_offset = swiotlb_align_offset(dev, orig_addr); > + if (tlb_offset < orig_addr_offset) { > + dev_WARN_ONCE(dev, 1, > + "Access before mapping start detected. orig offset %u, > requested offset %u.\n", > + orig_addr_offset, tlb_offset); > + return; > + } > + > + tlb_offset -= orig_addr_offset; > + if (tlb_offset > alloc_size) { > + dev_WARN_ONCE(dev, 1, > + "Buffer overflow detected. Allocation size: %zu. > Mapping size: %zu+%u.\n", > + alloc_size, size, tlb_offset); > + return; > + } > > orig_addr += tlb_offset; > alloc_size -= tlb_offset; > -- > 2.30.2
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