49 lines
1.7 KiB
Diff
49 lines
1.7 KiB
Diff
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memory: fix XENMEM_exchange error handling
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assign_pages() can fail due to the domain getting killed in parallel,
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which should not result in a hypervisor crash.
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Also delete a redundant put_gfn() - all relevant paths leading to the
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"fail" label already do this (and there are also paths where it was
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plain wrong). All of the put_gfn()-s got introduced by 51032ca058
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("Modify naming of queries into the p2m"), including the otherwise
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unneeded initializer for k (with even a kind of misleading comment -
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the compiler warning could actually have served as a hint that the use
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is wrong).
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This is XSA-159.
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Acked-by: Ian Campbell <ian.campbell@citrix.com>
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Index: xen-4.6.0-testing/xen/common/memory.c
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===================================================================
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--- xen-4.6.0-testing.orig/xen/common/memory.c
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+++ xen-4.6.0-testing/xen/common/memory.c
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@@ -328,7 +328,7 @@ static long memory_exchange(XEN_GUEST_HA
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PAGE_LIST_HEAD(out_chunk_list);
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unsigned long in_chunk_order, out_chunk_order;
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xen_pfn_t gpfn, gmfn, mfn;
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- unsigned long i, j, k = 0; /* gcc ... */
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+ unsigned long i, j, k;
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unsigned int memflags = 0;
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long rc = 0;
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struct domain *d;
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@@ -566,11 +566,12 @@ static long memory_exchange(XEN_GUEST_HA
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fail:
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/* Reassign any input pages we managed to steal. */
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while ( (page = page_list_remove_head(&in_chunk_list)) )
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- {
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- put_gfn(d, gmfn + k--);
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if ( assign_pages(d, page, 0, MEMF_no_refcount) )
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- BUG();
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- }
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+ {
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+ BUG_ON(!d->is_dying);
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+ if ( test_and_clear_bit(_PGC_allocated, &page->count_info) )
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+ put_page(page);
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+ }
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dying:
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rcu_unlock_domain(d);
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