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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Jan Beulich <jbeulich@suse.com>,
	Juergen Gross <jgross@suse.com>
Subject: [PATCH 4.4 25/35] Xen/x86: dont bail early from clear_foreign_p2m_mapping()
Date: Mon, 22 Feb 2021 13:36:21 +0100
Message-ID: <20210222121021.674569025@linuxfoundation.org> (raw)
In-Reply-To: <20210222121013.581198717@linuxfoundation.org>

From: Jan Beulich <jbeulich@suse.com>

commit a35f2ef3b7376bfd0a57f7844bd7454389aae1fc upstream.

Its sibling (set_foreign_p2m_mapping()) as well as the sibling of its
only caller (gnttab_map_refs()) don't clean up after themselves in case
of error. Higher level callers are expected to do so. However, in order
for that to really clean up any partially set up state, the operation
should not terminate upon encountering an entry in unexpected state. It
is particularly relevant to notice here that set_foreign_p2m_mapping()
would skip setting up a p2m entry if its grant mapping failed, but it
would continue to set up further p2m entries as long as their mappings
succeeded.

Arguably down the road set_foreign_p2m_mapping() may want its page state
related WARN_ON() also converted to an error return.

This is part of XSA-361.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/xen/p2m.c |   12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -763,17 +763,15 @@ int clear_foreign_p2m_mapping(struct gnt
 		unsigned long mfn = __pfn_to_mfn(page_to_pfn(pages[i]));
 		unsigned long pfn = page_to_pfn(pages[i]);
 
-		if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT)) {
+		if (mfn != INVALID_P2M_ENTRY && (mfn & FOREIGN_FRAME_BIT))
+			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+		else
 			ret = -EINVAL;
-			goto out;
-		}
-
-		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 	}
 	if (kunmap_ops)
 		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
-						kunmap_ops, count);
-out:
+						kunmap_ops, count) ?: ret;
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);



  parent reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-22 12:35 [PATCH 4.4 00/35] 4.4.258-rc1 review Greg Kroah-Hartman
2021-02-22 12:35 ` [PATCH 4.4 01/35] tracing: Do not count ftrace events in top level enable output Greg Kroah-Hartman
2021-02-22 12:35 ` [PATCH 4.4 02/35] fgraph: Initialize tracing_graph_pause at task creation Greg Kroah-Hartman
2021-02-22 12:35 ` [PATCH 4.4 03/35] af_key: relax availability checks for skb size calculation Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 04/35] iwlwifi: pcie: add a NULL check in iwl_pcie_txq_unmap Greg Kroah-Hartman
2021-02-25  6:04   ` Nobuhiro Iwamatsu
2021-02-25  8:14     ` Greg Kroah-Hartman
2021-02-25  8:47       ` Nobuhiro Iwamatsu
2021-02-22 12:36 ` [PATCH 4.4 05/35] iwlwifi: mvm: guard against device removal in reprobe Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 06/35] SUNRPC: Move simple_get_bytes and simple_get_netobj into private header Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 07/35] SUNRPC: Handle 0 length opaque XDR object data properly Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 08/35] lib/string: Add strscpy_pad() function Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 09/35] include/trace/events/writeback.h: fix -Wstringop-truncation warnings Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 10/35] memcg: fix a crash in wb_workfn when a device disappears Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 11/35] squashfs: add more sanity checks in id lookup Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 12/35] squashfs: add more sanity checks in inode lookup Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 13/35] squashfs: add more sanity checks in xattr id lookup Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 14/35] memblock: do not start bottom-up allocations with kernel_end Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 15/35] netfilter: xt_recent: Fix attempt to update deleted entry Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 16/35] h8300: fix PREEMPTION build, TI_PRE_COUNT undefined Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 17/35] usb: dwc3: ulpi: fix checkpatch warning Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 18/35] usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 19/35] net: watchdog: hold device global xmit lock during tx disable Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 20/35] vsock: fix locking in vsock_shutdown() Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 21/35] x86/build: Disable CET instrumentation in the kernel for 32-bit too Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 22/35] trace: Use -mcount-record for dynamic ftrace Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 23/35] tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcount Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 24/35] tracing: Avoid calling cc-option -mrecord-mcount for every Makefile Greg Kroah-Hartman
2021-02-22 12:36 ` Greg Kroah-Hartman [this message]
2021-02-22 12:36 ` [PATCH 4.4 26/35] Xen/x86: also check kernel mapping in set_foreign_p2m_mapping() Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 27/35] Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages() Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 28/35] Xen/gntdev: correct error checking " Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 29/35] xen/arm: dont ignore return errors from set_phys_to_machine Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 30/35] xen-blkback: dont "handle" error by BUG() Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 31/35] xen-netback: " Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 32/35] xen-scsiback: " Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 33/35] xen-blkback: fix error handling in xen_blkbk_map() Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 34/35] scsi: qla2xxx: Fix crash during driver load on big endian machines Greg Kroah-Hartman
2021-02-22 12:36 ` [PATCH 4.4 35/35] kvm: check tlbs_dirty directly Greg Kroah-Hartman
2021-02-22 18:37 ` [PATCH 4.4 00/35] 4.4.258-rc1 review Pavel Machek
2021-02-22 21:26 ` Guenter Roeck
2021-02-23 12:13 ` Naresh Kamboju
2021-02-23 21:26 ` Shuah Khan

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