diff options
Diffstat (limited to '0035-x86-shadow-drop-replace-bogus-assertions.patch')
| -rw-r--r-- | 0035-x86-shadow-drop-replace-bogus-assertions.patch | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/0035-x86-shadow-drop-replace-bogus-assertions.patch b/0035-x86-shadow-drop-replace-bogus-assertions.patch new file mode 100644 index 0000000..55e9f62 --- /dev/null +++ b/0035-x86-shadow-drop-replace-bogus-assertions.patch @@ -0,0 +1,71 @@ +From 9fdb4f17656f74b35af0882b558e44832ff00b5f Mon Sep 17 00:00:00 2001 +From: Jan Beulich <jbeulich@suse.com> +Date: Mon, 31 Oct 2022 13:24:33 +0100 +Subject: [PATCH 35/87] x86/shadow: drop (replace) bogus assertions +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +The addition of a call to shadow_blow_tables() from shadow_teardown() +has resulted in the "no vcpus" related assertion becoming triggerable: +If domain_create() fails with at least one page successfully allocated +in the course of shadow_enable(), or if domain_create() succeeds and +the domain is then killed without ever invoking XEN_DOMCTL_max_vcpus. +Note that in-tree tests (test-resource and test-tsx) do exactly the +latter of these two. + +The assertion's comment was bogus anyway: Shadow mode has been getting +enabled before allocation of vCPU-s for quite some time. Convert the +assertion to a conditional: As long as there are no vCPU-s, there's +nothing to blow away. + +Fixes: e7aa55c0aab3 ("x86/p2m: free the paging memory pool preemptively") +Reported-by: Andrew Cooper <andrew.cooper3@citrix.com> + +A similar assertion/comment pair exists in _shadow_prealloc(); the +comment is similarly bogus, and the assertion could in principle trigger +e.g. when shadow_alloc_p2m_page() is called early enough. Replace those +at the same time by a similar early return, here indicating failure to +the caller (which will generally lead to the domain being crashed in +shadow_prealloc()). + +Signed-off-by: Jan Beulich <jbeulich@suse.com> +Acked-by: Roger Pau Monné <roger.pau@citrix.com> +Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> +master commit: a92dc2bb30ba65ae25d2f417677eb7ef9a6a0fef +master date: 2022-10-24 15:46:11 +0200 +--- + xen/arch/x86/mm/shadow/common.c | 10 ++++++---- + 1 file changed, 6 insertions(+), 4 deletions(-) + +diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c +index 3b0d781991b5..1de0139742f7 100644 +--- a/xen/arch/x86/mm/shadow/common.c ++++ b/xen/arch/x86/mm/shadow/common.c +@@ -943,8 +943,9 @@ static bool __must_check _shadow_prealloc(struct domain *d, unsigned int pages) + /* No reclaim when the domain is dying, teardown will take care of it. */ + return false; + +- /* Shouldn't have enabled shadows if we've no vcpus. */ +- ASSERT(d->vcpu && d->vcpu[0]); ++ /* Nothing to reclaim when there are no vcpus yet. */ ++ if ( !d->vcpu[0] ) ++ return false; + + /* Stage one: walk the list of pinned pages, unpinning them */ + perfc_incr(shadow_prealloc_1); +@@ -1034,8 +1035,9 @@ void shadow_blow_tables(struct domain *d) + mfn_t smfn; + int i; + +- /* Shouldn't have enabled shadows if we've no vcpus. */ +- ASSERT(d->vcpu && d->vcpu[0]); ++ /* Nothing to do when there are no vcpus yet. */ ++ if ( !d->vcpu[0] ) ++ return; + + /* Pass one: unpin all pinned pages */ + foreach_pinned_shadow(d, sp, t) +-- +2.37.4 + |