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swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"
commit e9696d259d0fb5d239e8c28ca41089838ea76d13 upstream.
kernel/dma/swiotlb.c:swiotlb_init gets called first and tries to
allocate a buffer for the swiotlb. It does so by calling
memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE);
If the allocation must fail, no_iotlb_memory is set.
Later during initialization swiotlb-xen comes in
(drivers/xen/swiotlb-xen.c:xen_swiotlb_init) and given that io_tlb_start
is != 0, it thinks the memory is ready to use when actually it is not.
When the swiotlb is actually needed, swiotlb_tbl_map_single gets called
and since no_iotlb_memory is set the kernel panics.
Instead, if swiotlb-xen.c:xen_swiotlb_init knew the swiotlb hadn't been
initialized, it would do the initialization itself, which might still
succeed.
Fix the panic by setting io_tlb_start to 0 on swiotlb initialization
failure, and also by setting no_iotlb_memory to false on swiotlb
initialization success.
Fixes: ac2cbab21f
("x86: Don't panic if can not alloc buffer for swiotlb")
Reported-by: Elliott Mitchell <ehem+xen@m5p.com>
Tested-by: Elliott Mitchell <ehem+xen@m5p.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
2cd21fe5bc
commit
98901bff58
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@ -230,6 +230,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
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io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
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io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
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}
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}
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io_tlb_index = 0;
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io_tlb_index = 0;
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no_iotlb_memory = false;
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if (verbose)
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if (verbose)
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swiotlb_print_info();
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swiotlb_print_info();
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@ -261,9 +262,11 @@ swiotlb_init(int verbose)
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if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
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if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
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return;
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return;
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if (io_tlb_start)
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if (io_tlb_start) {
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memblock_free_early(io_tlb_start,
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memblock_free_early(io_tlb_start,
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PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
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PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
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io_tlb_start = 0;
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}
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pr_warn("Cannot allocate buffer");
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pr_warn("Cannot allocate buffer");
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no_iotlb_memory = true;
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no_iotlb_memory = true;
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}
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}
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@ -361,6 +364,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
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io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
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io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
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}
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}
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io_tlb_index = 0;
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io_tlb_index = 0;
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no_iotlb_memory = false;
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swiotlb_print_info();
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swiotlb_print_info();
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