Patch "virtio_balloon: prevent uninitialized variable use" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    virtio_balloon: prevent uninitialized variable use

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio_balloon-prevent-uninitialized-variable-use.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From f0bb2d50dfcc519f06f901aac88502be6ff1df2c Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 28 Mar 2017 18:46:59 +0200
Subject: virtio_balloon: prevent uninitialized variable use

From: Arnd Bergmann <arnd@arndb.de>

commit f0bb2d50dfcc519f06f901aac88502be6ff1df2c upstream.

The latest gcc-7.0.1 snapshot reports a new warning:

virtio/virtio_balloon.c: In function 'update_balloon_stats':
virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized]
virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized]
virtio/virtio_balloon.c:261:56: error: 'events[18]' is used uninitialized in this function [-Werror=uninitialized]
virtio/virtio_balloon.c:262:56: error: 'events[17]' is used uninitialized in this function [-Werror=uninitialized]

This seems absolutely right, so we should add an extra check to
prevent copying uninitialized stack data into the statistics.
>>From all I can tell, this has been broken since the statistics code
was originally added in 2.6.34.

Fixes: 9564e138b1f6 ("virtio: Add memory statistics reporting to the balloon driver (V4)")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/virtio/virtio_balloon.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -239,12 +239,14 @@ static void update_balloon_stats(struct
 	all_vm_events(events);
 	si_meminfo(&i);
 
+#ifdef CONFIG_VM_EVENT_COUNTERS
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
 				pages_to_bytes(events[PSWPIN]));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT,
 				pages_to_bytes(events[PSWPOUT]));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
+#endif
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE,
 				pages_to_bytes(i.freeram));
 	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT,


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.4/kasan-rework-kconfig-settings.patch
queue-4.4/hdpvr-hide-unused-variable.patch
queue-4.4/mtd-ichxrom-maybe-uninitialized-with-gcc-4.9.patch
queue-4.4/profile-hide-unused-functions-when-config_proc_fs.patch
queue-4.4/perf-x86-shut-up-false-positive-wmaybe-uninitialized-warning.patch
queue-4.4/hwrng-exynos-use-__maybe_unused-to-hide-pm-functions.patch
queue-4.4/usb-cdc_subset-only-build-when-one-driver-is-enabled.patch
queue-4.4/ipv4-ipconfig-avoid-unused-ic_proto_used-symbol.patch
queue-4.4/revert-power-bq27xxx_battery-remove-unneeded-dependency-in-kconfig.patch
queue-4.4/go7007-add-media_camera_support-dependency.patch
queue-4.4/scsi-advansys-fix-build-warning-for-pci-n.patch
queue-4.4/ssb-mark-ssb_bus_register-as-__maybe_unused.patch
queue-4.4/tty-cyclades-cyz_interrupt-is-only-used-for-pci.patch
queue-4.4/infiniband-cxgb4-use-pr-format-string-for-printing-resources.patch
queue-4.4/video-fbdev-via-remove-possibly-unused-variables.patch
queue-4.4/binfmt_elf-compat-avoid-unused-function-warning.patch
queue-4.4/drm-gma500-remove-helper-function.patch
queue-4.4/fbdev-s6e8ax0-avoid-unused-function-warnings.patch
queue-4.4/netfilter-ipvs-avoid-unused-variable-warnings.patch
queue-4.4/idle-i7300-add-pci-dependency.patch
queue-4.4/b2c2-flexcop-avoid-unused-function-warnings.patch
queue-4.4/fbdev-auo_k190x-avoid-unused-function-warnings.patch
queue-4.4/cw1200-fix-bogus-maybe-uninitialized-warning.patch
queue-4.4/x86-build-silence-the-build-with-make-s.patch
queue-4.4/gpio-xgene-mark-pm-functions-as-__maybe_unused.patch
queue-4.4/kvm-add-x86_local_apic-dependency.patch
queue-4.4/arm-tegra-select-usb_ulpi-from-ehci-rather-than-platform.patch
queue-4.4/asoc-mediatek-add-i2c-dependency.patch
queue-4.4/reiserfs-avoid-a-wmaybe-uninitialized-warning.patch
queue-4.4/scsi-advansys-fix-uninitialized-data-access.patch
queue-4.4/mtd-sh_flctl-pass-fifo-as-physical-address.patch
queue-4.4/driver-core-use-dev-argument-in-dev_dbg_ratelimited-stub.patch
queue-4.4/modsign-hide-openssl-output-in-silent-builds.patch
queue-4.4/net-hp100-remove-unnecessary-ifdefs.patch
queue-4.4/genirq-msi-add-stubs-for-get_cached_msi_msg-pci_write_msi_msg.patch
queue-4.4/asoc-intel-kconfig-fix-build-when-acpi-is-not-enabled.patch
queue-4.4/asoc-ux500-add-module_license-tag.patch
queue-4.4/wireless-cw1200-use-__maybe_unused-to-hide-pm-functions_.patch
queue-4.4/mptfusion-hide-unused-seq_mpt_print_ioc_summary-function.patch
queue-4.4/tlan-avoid-unused-label-with-pci-n.patch
queue-4.4/usb-musb-ux500-remove-duplicate-check-for-dma_is_compatible.patch
queue-4.4/mtd-cfi-enforce-valid-geometry-configuration.patch
queue-4.4/thermal-spear-use-__maybe_unused-for-pm-functions.patch
queue-4.4/x86-microcode-amd-change-load_microcode_amd-s-param-to-bool-to-fix-preemptibility-bug.patch
queue-4.4/video-fbdev-mmp-add-module_license.patch
queue-4.4/fbdev-sis-enforce-selection-of-at-least-one-backend.patch
queue-4.4/x86-boot-avoid-warning-for-zero-filling-.bss.patch
queue-4.4/power-bq27xxx_battery-mark-some-symbols-__maybe_unused.patch
queue-4.4/scsi-mvumi-use-__maybe_unused-to-hide-pm-functions.patch
queue-4.4/usb-phy-msm-add-regulator-dependency.patch
queue-4.4/isdn-icn-remove-a-warning.patch
queue-4.4/ncr5380-shut-up-gcc-indentation-warning.patch
queue-4.4/arm64-dts-add-cooling-cells-to-cpu-nodes.patch
queue-4.4/vmxnet3-prevent-building-with-64k-pages.patch
queue-4.4/genksyms-fix-segfault-with-invalid-declarations.patch
queue-4.4/x86-platform-add-pci-dependency-for-punit_atom_debug.patch
queue-4.4/target-user-fix-cast-from-pointer-to-phys_addr_t.patch
queue-4.4/rtlwifi-fix-gcc-6-indentation-warning.patch
queue-4.4/alsa-hda-ca0132-fix-possible-null-pointer-use.patch
queue-4.4/thermal-fix-intel_soc_dts_iosf_core-dependencies.patch
queue-4.4/arm64-define-bug-instruction-without-config_bug.patch
queue-4.4/v4l-remove-media_tuner-dependency-for-video_tuner.patch
queue-4.4/tc358743-fix-register-i2c_rd-wr-functions.patch
queue-4.4/scsi-fdomain-drop-fdomain_pci_tbl-when-built-in.patch
queue-4.4/scsi-initio-remove-duplicate-module-device-table.patch
queue-4.4/netlink-fix-nla_put_-u8-u16-u32-for-kasan.patch
queue-4.4/x86-fpu-math-emu-fix-possible-uninitialized-variable-use.patch
queue-4.4/asoc-rockchip-use-__maybe_unused-to-hide-st_irq_syscfg_resume.patch
queue-4.4/staging-ste_rmi4-avoid-unused-function-warnings.patch
queue-4.4/em28xx-only-use-mt9v011-if-camera-support-is-enabled.patch
queue-4.4/pwc-hide-unused-label.patch
queue-4.4/input-tca8418_keypad-hide-gcc-4.9-wmaybe-uninitialized-warning.patch
queue-4.4/fbdev-sm712fb-avoid-unused-function-warnings.patch
queue-4.4/isdn-sc-work-around-type-mismatch-warning.patch
queue-4.4/tty-hvc_xen-hide-xen_console_remove-when-unused.patch
queue-4.4/virtio_balloon-prevent-uninitialized-variable-use.patch
queue-4.4/drm-nouveau-hide-gcc-4.9-wmaybe-uninitialized.patch
queue-4.4/dell-wmi-dell-laptop-depends-dmi.patch
queue-4.4/x86-add-multiuser-dependency-for-kvm.patch
queue-4.4/md-avoid-warning-for-32-bit-sector_t.patch
queue-4.4/isdn-eicon-reduce-stack-size-of-sig_ind-function.patch