Al Viro [Mon, 15 Apr 2019 23:45:26 +0000 (19:45 -0400)]
gfs2: switch to ->free_inode()
... and use GFS2_I() to get the containing gfs2_inode by inode;
yes, we can feed the address of the first member of structure
to kmem_cache_free(), but let's do it in an obviously safe way.
Al Viro [Wed, 10 Apr 2019 18:43:44 +0000 (14:43 -0400)]
new inode method: ->free_inode()
A lot of ->destroy_inode() instances end with call_rcu() of a callback
that does RCU-delayed part of freeing. Introduce a new method for
doing just that, with saner signature.
Rules:
->destroy_inode ->free_inode
f g immediate call of f(),
RCU-delayed call of g()
f NULL immediate call of f(),
no RCU-delayed calls
NULL g RCU-delayed call of g()
NULL NULL RCU-delayed default freeing
IOW, NULL ->free_inode gives the same behaviour as now.
Note that NULL, NULL is equivalent to NULL, free_inode_nonrcu; we could
mandate the latter form, but that would have very little benefit beyond
making rules a bit more symmetric. It would break backwards compatibility,
require extra boilerplate and expected semantics for (NULL, NULL) pair
would have no use whatsoever...
Al Viro [Wed, 10 Apr 2019 18:04:34 +0000 (14:04 -0400)]
apparmorfs: fix use-after-free on symlink traversal
symlink body shouldn't be freed without an RCU delay. Switch apparmorfs
to ->destroy_inode() and use of call_rcu(); free both the inode and symlink
body in the callback.
Al Viro [Wed, 10 Apr 2019 18:03:45 +0000 (14:03 -0400)]
securityfs: fix use-after-free on symlink traversal
symlink body shouldn't be freed without an RCU delay. Switch securityfs
to ->destroy_inode() and use of call_rcu(); free both the inode and symlink
body in the callback.
Merge tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull ARM SoC fixes from Olof Johansson:
"A collection of fixes from the last few weeks. Most of them are
smaller tweaks and fixes to DT and hardware descriptions for boards.
Some of the more significant ones are:
- eMMC and RGMII stability tweaks for rk3288
- DDC fixes for Rock PI 4
- Audio fixes for two TI am335x eval boards
- D_CAN clock fix for am335x
- Compilation fixes for clang
- !HOTPLUG_CPU compilation fix for one of the new platforms this
release (milbeaut)
- A revert of a gpio fix for nomadik that instead was fixed in the
gpio subsystem
- Whitespace fix for the DT JSON schema (no tabs allowed)"
* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (25 commits)
ARM: milbeaut: fix build with !CONFIG_HOTPLUG_CPU
ARM: iop: don't use using 64-bit DMA masks
ARM: orion: don't use using 64-bit DMA masks
Revert "ARM: dts: nomadik: Fix polarity of SPI CS"
dt-bindings: cpu: Fix JSON schema
arm/mach-at91/pm : fix possible object reference leak
ARM: dts: at91: Fix typo in ISC_D0 on PC9
ARM: dts: Fix dcan clkctrl clock for am3
reset: meson-audio-arb: Fix missing .owner setting of reset_controller_dev
dt-bindings: reset: meson-g12a: Add missing USB2 PHY resets
ARM: dts: rockchip: Remove #address/#size-cells from rk3288-veyron gpio-keys
ARM: dts: rockchip: Remove #address/#size-cells from rk3288 mipi_dsi
ARM: dts: rockchip: Fix gpu opp node names for rk3288
ARM: dts: am335x-evmsk: Correct the regulators for the audio codec
ARM: dts: am335x-evm: Correct the regulators for the audio codec
ARM: OMAP2+: add missing of_node_put after of_device_is_available
ARM: OMAP1: ams-delta: Fix broken GPIO ID allocation
arm64: dts: stratix10: add the sysmgr-syscon property from the gmac's
arm64: dts: rockchip: fix rk3328 sdmmc0 write errors
arm64: dts: rockchip: fix rk3328 rgmii high tx error rate
...
Merge tag 'for-linus-20190407' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- Fixups for the pf/pcd queue handling (YueHaibing)
- Revert of the three direct issue changes as they have been proven to
cause an issue with dm-mpath (Bart)
- Plug rq_count reset fix (Dongli)
- io_uring double free in fileset registration error handling (me)
- Make null_blk handle bad numa node passed in (John)
- BFQ ifdef fix (Konstantin)
- Flush queue leak fix (Shenghui)
- Plug trace fix (Yufen)
* tag 'for-linus-20190407' of git://git.kernel.dk/linux-block:
xsysace: Fix error handling in ace_setup
null_blk: prevent crash from bad home_node value
block: Revert v5.0 blk_mq_request_issue_directly() changes
paride/pcd: Fix potential NULL pointer dereference and mem leak
blk-mq: do not reset plug->rq_count before the list is sorted
paride/pf: Fix potential NULL pointer dereference
io_uring: fix double free in case of fileset regitration failure
blk-mq: add trace block plug and unplug for multiple queues
block: use blk_free_flush_queue() to free hctx->fq in blk_mq_init_hctx
block/bfq: fix ifdef for CONFIG_BFQ_GROUP_IOSCHED=y
Arnd Bergmann [Wed, 13 Mar 2019 21:19:16 +0000 (22:19 +0100)]
ARM: milbeaut: fix build with !CONFIG_HOTPLUG_CPU
When HOTPLUG_CPU is disabled, some fields in the smp operations
are not available or needed:
arch/arm/mach-milbeaut/platsmp.c:90:3: error: field designator 'cpu_die' does not refer to any field in type
'struct smp_operations'
.cpu_die = m10v_cpu_die,
^
arch/arm/mach-milbeaut/platsmp.c:91:3: error: field designator 'cpu_kill' does not refer to any field in type
'struct smp_operations'
.cpu_kill = m10v_cpu_kill,
^
Hide them in an #ifdef like the other platforms do.
Fixes: 9fb29c734f9e ("ARM: milbeaut: Add basic support for Milbeaut m10v SoC") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Olof Johansson <olof@lixom.net>
can you please revert this patch. It was the wrong solution to the
wrong problem, and I must have acted in stress. Andrey fixed the
real bug in a proper way in these commits:
Olof Johansson [Sun, 7 Apr 2019 22:16:38 +0000 (15:16 -0700)]
Merge tag 'omap-for-v5.1/fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into arm/fixes
Fixes for omaps for v5.1-rc cycle
Few small fixes for omap variants:
- Fix ams-delta gpio IDs
- Add missing of_node_put for omapdss platform init code
- Fix unconfigured audio regulators for two am335x boards
- Fix use of wrong offset for am335x d_can clocks
* tag 'omap-for-v5.1/fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: dts: Fix dcan clkctrl clock for am3
ARM: dts: am335x-evmsk: Correct the regulators for the audio codec
ARM: dts: am335x-evm: Correct the regulators for the audio codec
ARM: OMAP2+: add missing of_node_put after of_device_is_available
ARM: OMAP1: ams-delta: Fix broken GPIO ID allocation
Olof Johansson [Sun, 7 Apr 2019 22:16:09 +0000 (15:16 -0700)]
Merge tag 'at91-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux into arm/fixes
AT91 fixes for 5.1
- fix a typo in sama5d2 pinmuxing which concerns the ISC data 0 signal
- fix a kobject reference leak
* tag 'at91-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
arm/mach-at91/pm : fix possible object reference leak
ARM: dts: at91: Fix typo in ISC_D0 on PC9
Olof Johansson [Sun, 7 Apr 2019 22:15:31 +0000 (15:15 -0700)]
Merge tag 'v5.1-rockchip-dtfixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip into arm/fixes
Fixes for dtc warnings, fixes for ethernet transfers on rk3328,
sd-card related fixes on both rk3328 ans rk3288-tinker and a
regulator fix on rock64 and making ddc actually work on the
Rock PI 4 due to missing the ddc bus.
* tag 'v5.1-rockchip-dtfixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
ARM: dts: rockchip: Remove #address/#size-cells from rk3288-veyron gpio-keys
ARM: dts: rockchip: Remove #address/#size-cells from rk3288 mipi_dsi
ARM: dts: rockchip: Fix gpu opp node names for rk3288
arm64: dts: rockchip: fix rk3328 sdmmc0 write errors
arm64: dts: rockchip: fix rk3328 rgmii high tx error rate
ARM: dts: rockchip: Fix SD card detection on rk3288-tinker
arm64: dts: rockchip: Fix vcc_host1_5v GPIO polarity on rk3328-rock64
ARM: dts: rockchip: fix rk3288 cpu opp node reference
arm64: dts: rockchip: add DDC bus on Rock Pi 4
arm64: dts: rockchip: fix rk3328-roc-cc gmac2io tx/rx_delay
Olof Johansson [Sun, 7 Apr 2019 22:14:30 +0000 (15:14 -0700)]
Merge tag 'stratix10_fix_for_v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux into arm/fixes
arm64: dts: stratix10: fix emac loading warning
- Add missing "altr,sysmgr-syscon" property to all gmac nodes
* tag 'stratix10_fix_for_v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux:
arm64: dts: stratix10: add the sysmgr-syscon property from the gmac's
Olof Johansson [Sun, 7 Apr 2019 22:14:00 +0000 (15:14 -0700)]
Merge tag 'reset-fixes-for-v5.1' of git://git.pengutronix.de/pza/linux into arm/fixes
Reset controller fixes for v5.1
This tag adds missing USB PHY reset lines to the Meson G12A reset
controller header and fixes the Meson Audio ARB driver to prevent
module unloading while it is in use.
* tag 'reset-fixes-for-v5.1' of git://git.pengutronix.de/pza/linux:
reset: meson-audio-arb: Fix missing .owner setting of reset_controller_dev
dt-bindings: reset: meson-g12a: Add missing USB2 PHY resets
Maxime Ripard [Mon, 18 Mar 2019 10:05:21 +0000 (11:05 +0100)]
dt-bindings: cpu: Fix JSON schema
Commit fd73403a4862 ("dt-bindings: arm: Add SMP enable-method for
Milbeaut") added support for a new cpu enable-method, but did so using
tabulations to ident. This is however invalid in the syntax, and resulted
in a failure when trying to use that schemas for validation.
Use spaces instead of tabs to indent to fix this.
Fixes: fd73403a4862 ("dt-bindings: arm: Add SMP enable-method for Milbeaut") Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Reviewed-by: Rob Herring <robh@kernel.org> Acked-by: Sugaya Taichi <sugaya.taichi@socionext.com> Signed-off-by: Olof Johansson <olof@lixom.net>
Merge tag 'for-linus-5.1b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"One minor fix and a small cleanup for the xen privcmd driver"
* tag 'for-linus-5.1b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: Prevent buffer overflow in privcmd ioctl
xen: use struct_size() helper in kzalloc()
Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"Five small fixes. Four in three drivers: qedi, lpfc and storvsc. The
final one is labelled core, but merely adds a dh rdac entry for Lenovo
systems"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: lpfc: Fix missing wakeups on abort threads
scsi: storvsc: Reduce default ring buffer size to 128 Kbytes
scsi: storvsc: Fix calculation of sub-channel count
scsi: core: add new RDAC LENOVO/DE_Series device
scsi: qedi: remove declaration of nvm_image from stack
Merge branch 'parisc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc fixes from Helge Deller:
"A 32-bit boot regression fix introduced in the merge window, a QEMU
detection fix and two fixes by Sven regarding ptrace & kprobes"
* 'parisc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: Detect QEMU earlier in boot process
parisc: also set iaoq_b in instruction_pointer_set()
parisc: regs_return_value() should return gpr28
Revert: parisc: Use F_EXTEND() macro in iosapic code
While adding LASI support to QEMU, I noticed that the QEMU detection in
the kernel happens much too late. For example, when a LASI chip is found
by the kernel, it registers the LASI LED driver as well. But when we
run on QEMU it makes sense to avoid spending unnecessary CPU cycles, so
we need to access the running_on_QEMU flag earlier than before.
This patch now makes the QEMU detection the fist task of the Linux
kernel by moving it to where the kernel enters the C-coding.
Sven Schnelle [Thu, 4 Apr 2019 16:16:04 +0000 (18:16 +0200)]
parisc: also set iaoq_b in instruction_pointer_set()
When setting the instruction pointer on PA-RISC we also need
to set the back of the instruction queue to the new offset, otherwise
we will execute on instruction from the new location, and jumping
back to the old location stored in iaoq_b.
Sven Schnelle [Thu, 4 Apr 2019 16:16:03 +0000 (18:16 +0200)]
parisc: regs_return_value() should return gpr28
While working on kretprobes for PA-RISC I was wondering while the
kprobes sanity test always fails on kretprobes. This is caused by
returning gpr20 instead of gpr28.
Kirill Smelkov [Tue, 26 Mar 2019 22:20:43 +0000 (22:20 +0000)]
fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock
Commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per POSIX") added
locking for file.f_pos access and in particular made concurrent read and
write not possible - now both those functions take f_pos lock for the
whole run, and so if e.g. a read is blocked waiting for data, write will
deadlock waiting for that read to complete.
This caused regression for stream-like files where previously read and
write could run simultaneously, but after that patch could not do so
anymore. See e.g. commit 581d21a2d02a ("xenbus: fix deadlock on writes
to /proc/xen/xenbus") which fixes such regression for particular case of
/proc/xen/xenbus.
The patch that added f_pos lock in 2014 did so to guarantee POSIX thread
safety for read/write/lseek and added the locking to file descriptors of
all regular files. In 2014 that thread-safety problem was not new as it
was already discussed earlier in 2006.
However even though 2006'th version of Linus's patch was adding f_pos
locking "only for files that are marked seekable with FMODE_LSEEK (thus
avoiding the stream-like objects like pipes and sockets)", the 2014
version - the one that actually made it into the tree as 9c225f2655e3 -
is doing so irregardless of whether a file is seekable or not.
The reason that it did so is, probably, that there are many files that
are marked non-seekable, but e.g. their read implementation actually
depends on knowing current position to correctly handle the read. Some
examples:
Despite that, many nonseekable_open users implement read and write with
pure stream semantics - they don't depend on passed ppos at all. And for
those cases where read could wait for something inside, it creates a
situation similar to xenbus - the write could be never made to go until
read is done, and read is waiting for some, potentially external, event,
for potentially unbounded time -> deadlock.
Besides xenbus, there are 14 such places in the kernel that I've found
with semantic patch (see below):
drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write()
drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write()
drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write()
drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write()
net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write()
drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write()
drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write()
drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write()
net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write()
drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write()
drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write()
drivers/input/misc/uinput.c:400:1-17: ERROR: uinput_fops: .read() can deadlock .write()
drivers/infiniband/core/user_mad.c:985:7-23: ERROR: umad_fops: .read() can deadlock .write()
drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write()
In addition to the cases above another regression caused by f_pos
locking is that now FUSE filesystems that implement open with
FOPEN_NONSEEKABLE flag, can no longer implement bidirectional
stream-like files - for the same reason as above e.g. read can deadlock
write locking on file.f_pos in the kernel.
FUSE's FOPEN_NONSEEKABLE was added in 2008 in a7c1b990f715 ("fuse:
implement nonseekable open") to support OSSPD. OSSPD implements /dev/dsp
in userspace with FOPEN_NONSEEKABLE flag, with corresponding read and
write routines not depending on current position at all, and with both
read and write being potentially blocking operations:
Corresponding libfuse example/test also describes FOPEN_NONSEEKABLE as
"somewhat pipe-like files ..." with read handler not using offset.
However that test implements only read without write and cannot exercise
the deadlock scenario:
I've actually hit the read vs write deadlock for real while implementing
my FUSE filesystem where there is /head/watch file, for which open
creates separate bidirectional socket-like stream in between filesystem
and its user with both read and write being later performed
simultaneously. And there it is semantically not easy to split the
stream into two separate read-only and write-only channels:
1. We can't change nonseekable_open to include &~FMODE_ATOMIC_POS -
doing so would break many in-kernel nonseekable_open users which
actually use ppos in read/write handlers.
2. Add stream_open() to kernel to open stream-like non-seekable file
descriptors. Read and write on such file descriptors would never use
nor change ppos. And with that property on stream-like files read and
write will be running without taking f_pos lock - i.e. read and write
could be running simultaneously.
3. With semantic patch search and convert to stream_open all in-kernel
nonseekable_open users for which read and write actually do not
depend on ppos and where there is no other methods in file_operations
which assume @offset access.
4. Add FOPEN_STREAM to fs/fuse/ and open in-kernel file-descriptors via
steam_open if that bit is present in filesystem open reply.
It was tempting to change fs/fuse/ open handler to use stream_open
instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but
grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
and in particular GVFS which actually uses offset in its read and
write handlers
so if we would do such a change it will break a real user.
5. Add stream_open and FOPEN_STREAM handling to stable kernels starting
from v3.14+ (the kernel where 9c225f2655 first appeared).
This will allow to patch OSSPD and other FUSE filesystems that
provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE
in their open handler and this way avoid the deadlock on all kernel
versions. This should work because fs/fuse/ ignores unknown open
flags returned from a filesystem and so passing FOPEN_STREAM to a
kernel that is not aware of this flag cannot hurt. In turn the kernel
that is not aware of FOPEN_STREAM will be < v3.14 where just
FOPEN_NONSEEKABLE is sufficient to implement streams without read vs
write deadlock.
This patch adds stream_open, converts /proc/xen/xenbus to it and adds
semantic patch to automatically locate in-kernel places that are either
required to be converted due to read vs write deadlock, or that are just
safe to be converted because read and write do not use ppos and there
are no other funky methods in file_operations.
Regarding semantic patch I've verified each generated change manually -
that it is correct to convert - and each other nonseekable_open instance
left - that it is either not correct to convert there, or that it is not
converted due to current stream_open.cocci limitations.
The script also does not convert files that should be valid to convert,
but that currently have .llseek = noop_llseek or generic_file_llseek for
unknown reason despite file being opened with nonseekable_open (e.g.
drivers/input/mousedev.c)
Guenter Roeck [Tue, 19 Feb 2019 16:49:56 +0000 (08:49 -0800)]
xsysace: Fix error handling in ace_setup
If xace hardware reports a bad version number, the error handling code
in ace_setup() calls put_disk(), followed by queue cleanup. However, since
the disk data structure has the queue pointer set, put_disk() also
cleans and releases the queue. This results in blk_cleanup_queue()
accessing an already released data structure, which in turn may result
in a crash such as the following.
Fix the problem by setting the disk queue pointer to NULL before calling
put_disk(). A more comprehensive fix might be to rearrange the code
to check the hardware version before initializing data structures,
but I don't know if this would have undesirable side effects, and
it would increase the complexity of backporting the fix to older kernels.
Fixes: 74489a91dd43a ("Add support for Xilinx SystemACE CompactFlash interface") Acked-by: Michal Simek <michal.simek@xilinx.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Jens Axboe <axboe@kernel.dk>
John Pittman [Fri, 5 Apr 2019 21:42:45 +0000 (17:42 -0400)]
null_blk: prevent crash from bad home_node value
At module load, if the selected home_node value is greater than
the available numa nodes, the system will crash in
__alloc_pages_nodemask() due to a bad paging request. Prevent this
user error crash by detecting the bad value, logging an error, and
setting g_home_node back to the default of NUMA_NO_NODE.
Signed-off-by: John Pittman <jpittman@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge tag 'rtc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
Pull RTC fixes from Alexandre Belloni:
- Various alarm fixes for da9063, cros-ec and sh
- sd3078 manufacturer name fix as this was introduced this cycle
* tag 'rtc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
rtc: da9063: set uie_unsupported when relevant
rtc: sd3078: fix manufacturer name
rtc: sh: Fix invalid alarm warning for non-enabled alarm
rtc: cros-ec: Fail suspend/resume if wake IRQ can't be configured
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kernel/sysctl.c: fix out-of-bounds access when setting file-max
mm/util.c: fix strndup_user() comment
sh: fix multiple function definition build errors
MAINTAINERS: add maintainer and replacing reviewer ARM/NUVOTON NPCM
MAINTAINERS: fix bad pattern in ARM/NUVOTON NPCM
mm: writeback: use exact memcg dirty counts
psi: clarify the units used in pressure files
mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()
hugetlbfs: fix memory leak for resv_map
mm: fix vm_fault_t cast in VM_FAULT_GET_HINDEX()
lib/lzo: fix bugs for very short or empty input
include/linux/bitrev.h: fix constant bitrev
kmemleak: powerpc: skip scanning holes in the .bss section
lib/string.c: implement a basic bcmp
Will Deacon [Sat, 6 Apr 2019 01:39:38 +0000 (18:39 -0700)]
kernel/sysctl.c: fix out-of-bounds access when setting file-max
Commit 32a5ad9c2285 ("sysctl: handle overflow for file-max") hooked up
min/max values for the file-max sysctl parameter via the .extra1 and
.extra2 fields in the corresponding struct ctl_table entry.
Unfortunately, the minimum value points at the global 'zero' variable,
which is an int. This results in a KASAN splat when accessed as a long
by proc_doulongvec_minmax on 64-bit architectures:
| BUG: KASAN: global-out-of-bounds in __do_proc_doulongvec_minmax+0x5d8/0x6a0
| Read of size 8 at addr ffff2000133d1c20 by task systemd/1
|
| CPU: 0 PID: 1 Comm: systemd Not tainted 5.1.0-rc3-00012-g40b114779944 #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0x0/0x228
| show_stack+0x14/0x20
| dump_stack+0xe8/0x124
| print_address_description+0x60/0x258
| kasan_report+0x140/0x1a0
| __asan_report_load8_noabort+0x18/0x20
| __do_proc_doulongvec_minmax+0x5d8/0x6a0
| proc_doulongvec_minmax+0x4c/0x78
| proc_sys_call_handler.isra.19+0x144/0x1d8
| proc_sys_write+0x34/0x58
| __vfs_write+0x54/0xe8
| vfs_write+0x124/0x3c0
| ksys_write+0xbc/0x168
| __arm64_sys_write+0x68/0x98
| el0_svc_common+0x100/0x258
| el0_svc_handler+0x48/0xc0
| el0_svc+0x8/0xc
|
| The buggy address belongs to the variable:
| zero+0x0/0x40
|
| Memory state around the buggy address:
| ffff2000133d1b00: 00 00 00 00 00 00 00 00 fa fa fa fa 04 fa fa fa
| ffff2000133d1b80: fa fa fa fa 04 fa fa fa fa fa fa fa 04 fa fa fa
| >ffff2000133d1c00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00
| ^
| ffff2000133d1c80: fa fa fa fa 00 fa fa fa fa fa fa fa 00 00 00 00
| ffff2000133d1d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Fix the splat by introducing a unsigned long 'zero_ul' and using that
instead.
Link: http://lkml.kernel.org/r/20190403153409.17307-1-will.deacon@arm.com Fixes: 32a5ad9c2285 ("sysctl: handle overflow for file-max") Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Christian Brauner <christian@brauner.io> Cc: Kees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matteo Croce <mcroce@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrew Morton [Sat, 6 Apr 2019 01:39:34 +0000 (18:39 -0700)]
mm/util.c: fix strndup_user() comment
The kerneldoc misdescribes strndup_user()'s return value.
Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Timur Tabi <timur@freescale.com> Cc: Mihai Caraman <mihai.caraman@freescale.com> Cc: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Sat, 6 Apr 2019 01:39:30 +0000 (18:39 -0700)]
sh: fix multiple function definition build errors
Many of the sh CPU-types have their own plat_irq_setup() and
arch_init_clk_ops() functions, so these same (empty) functions in
arch/sh/boards/of-generic.c are not needed and cause build errors.
If there is some case where these empty functions are needed, they can
be retained by marking them as "__weak" while at the same time making
builds that do not need them succeed.
Fixes these build errors:
arch/sh/boards/of-generic.o: In function `plat_irq_setup':
(.init.text+0x134): multiple definition of `plat_irq_setup'
arch/sh/kernel/cpu/sh2/setup-sh7619.o:(.init.text+0x30): first defined here
arch/sh/boards/of-generic.o: In function `arch_init_clk_ops':
(.init.text+0x118): multiple definition of `arch_init_clk_ops'
arch/sh/kernel/cpu/sh2/clock-sh7619.o:(.init.text+0x0): first defined here
Link: http://lkml.kernel.org/r/9ee4e0c5-f100-86a2-bd4d-1d3287ceab31@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: kbuild test robot <lkp@intel.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the process of upstreaming architecture support for ARM/NUVOTON NPCM
include/dt-bindings/clock/nuvoton,npcm7xx-clks.h was renamed
include/dt-bindings/clock/nuvoton,npcm7xx-clock.h without updating
MAINTAINERS. This updates the MAINTAINERS pattern to match the new name
of this file.
Link: http://lkml.kernel.org/r/20190328235752.334462-1-tmaimon77@gmail.com Fixes: 6a498e06ba22 ("MAINTAINERS: Add entry for the Nuvoton NPCM architecture") Signed-off-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com> Reported-by: Joe Perches <joe@perches.com> Reviewed-by: Benjamin Fair <benjaminfair@google.com> Cc: Avi Fishman <avifishman70@gmail.com> Cc: Mukesh Ojha <mojha@codeaurora.org> Cc: Nancy Yuen <yuenn@google.com> Cc: Patrick Venture <venture@google.com> Cc: Tali Perry <tali.perry1@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit a983b5ebee57 ("mm: memcontrol: fix excessive complexity in
memory.stat reporting") memcg dirty and writeback counters are managed
as:
1) per-memcg per-cpu values in range of [-32..32]
2) per-memcg atomic counter
When a per-cpu counter cannot fit in [-32..32] it's flushed to the
atomic. Stat readers only check the atomic. Thus readers such as
balance_dirty_pages() may see a nontrivial error margin: 32 pages per
cpu.
Assuming 100 cpus:
4k x86 page_size: 13 MiB error per memcg
64k ppc page_size: 200 MiB error per memcg
Considering that dirty+writeback are used together for some decisions the
errors double.
This inaccuracy can lead to undeserved oom kills. One nasty case is
when all per-cpu counters hold positive values offsetting an atomic
negative value (i.e. per_cpu[*]=32, atomic=n_cpu*-32).
balance_dirty_pages() only consults the atomic and does not consider
throttling the next n_cpu*32 dirty pages. If the file_lru is in the
13..200 MiB range then there's absolutely no dirty throttling, which
burdens vmscan with only dirty+writeback pages thus resorting to oom
kill.
It could be argued that tiny containers are not supported, but it's more
subtle. It's the amount the space available for file lru that matters.
If a container has memory.max-200MiB of non reclaimable memory, then it
will also suffer such oom kills on a 100 cpu machine.
The following test reliably ooms without this patch. This patch avoids
oom kills.
$ cat test
mount -t cgroup2 none /dev/cgroup
cd /dev/cgroup
echo +io +memory > cgroup.subtree_control
mkdir test
cd test
echo 10M > memory.max
(echo $BASHPID > cgroup.procs && exec /memcg-writeback-stress /foo)
(echo $BASHPID > cgroup.procs && exec dd if=/dev/zero of=/foo bs=2M count=100)
$ cat memcg-writeback-stress.c
/*
* Dirty pages from all but one cpu.
* Clean pages from the non dirtying cpu.
* This is to stress per cpu counter imbalance.
* On a 100 cpu machine:
* - per memcg per cpu dirty count is 32 pages for each of 99 cpus
* - per memcg atomic is -99*32 pages
* - thus the complete dirty limit: sum of all counters 0
* - balance_dirty_pages() only sees atomic count -99*32 pages, which
* it max()s to 0.
* - So a workload can dirty -99*32 pages before balance_dirty_pages()
* cares.
*/
#define _GNU_SOURCE
#include <err.h>
#include <fcntl.h>
#include <sched.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/sysinfo.h>
#include <sys/types.h>
#include <unistd.h>
CPU_ZERO(&affinity);
CPU_SET(cpu, &affinity);
if (sched_setaffinity(0, sizeof(affinity), &affinity))
err(1, "sched_setaffinity");
}
static void dirty_on(int output_fd, int cpu)
{
int i, wrote;
set_affinity(cpu);
for (i = 0; i < 32; i++) {
for (wrote = 0; wrote < bufSize; ) {
int ret = write(output_fd, buf+wrote, bufSize-wrote);
if (ret == -1)
err(1, "write");
wrote += ret;
}
}
}
int main(int argc, char **argv)
{
int cpu, flush_cpu = 1, output_fd;
const char *output;
for (cpu = 0; cpu < get_nprocs(); cpu++) {
if (cpu != flush_cpu)
dirty_on(output_fd, cpu);
}
set_affinity(flush_cpu);
if (fsync(output_fd))
err(1, "fsync(%s)", output);
if (close(output_fd))
err(1, "close(%s)", output);
free(buf);
}
Make balance_dirty_pages() and wb_over_bg_thresh() work harder to
collect exact per memcg counters. This avoids the aforementioned oom
kills.
This does not affect the overhead of memory.stat, which still reads the
single atomic counter.
Why not use percpu_counter? memcg already handles cpus going offline, so
no need for that overhead from percpu_counter. And the percpu_counter
spinlocks are more heavyweight than is required.
It probably also makes sense to use exact dirty and writeback counters
in memcg oom reports. But that is saved for later.
Link: http://lkml.kernel.org/r/20190329174609.164344-1-gthelen@google.com Signed-off-by: Greg Thelen <gthelen@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> [4.16+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Waiman Long [Sat, 6 Apr 2019 01:39:14 +0000 (18:39 -0700)]
psi: clarify the units used in pressure files
The output of the PSI files show a bunch of numbers with no unit. The
psi.txt documentation file also does not indicate what units are used.
One can only find out by looking at the source code. The units are
percentage for the averages and useconds for the total. Make the
information easier to find by documenting the units in psi.txt.
Link: http://lkml.kernel.org/r/20190402193810.3450-1-longman@redhat.com Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Sat, 6 Apr 2019 01:39:06 +0000 (18:39 -0700)]
hugetlbfs: fix memory leak for resv_map
When mknod is used to create a block special file in hugetlbfs, it will
allocate an inode and kmalloc a 'struct resv_map' via resv_map_alloc().
inode->i_mapping->private_data will point the newly allocated resv_map.
However, when the device special file is opened bd_acquire() will set
inode->i_mapping to bd_inode->i_mapping. Thus the pointer to the
allocated resv_map is lost and the structure is leaked.
Programs to reproduce:
mount -t hugetlbfs nodev hugetlbfs
mknod hugetlbfs/dev b 0 0
exec 30<> hugetlbfs/dev
umount hugetlbfs/
resv_map structures are only needed for inodes which can have associated
page allocations. To fix the leak, only allocate resv_map for those
inodes which could possibly be associated with page allocations.
Link: http://lkml.kernel.org/r/20190401213101.16476-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reported-by: Yufen Yu <yuyufen@huawei.com> Suggested-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Rodgman [Sat, 6 Apr 2019 01:38:58 +0000 (18:38 -0700)]
lib/lzo: fix bugs for very short or empty input
For very short input data (0 - 1 bytes), lzo-rle was not behaving
correctly. Fix this behaviour and update documentation accordingly.
For zero-length input, lzo v0 outputs an end-of-stream marker only,
which was misinterpreted by lzo-rle as a bitstream version number.
Ensure bitstream versions > 0 require a minimum stream length of 5.
Also fixes a bug in handling the tail for very short inputs when a
bitstream version is present.
clang points out with hundreds of warnings that the bitrev macros have a
problem with constant input:
drivers/hwmon/sht15.c:187:11: error: variable '__x' is uninitialized when used within its own initialization
[-Werror,-Wuninitialized]
u8 crc = bitrev8(data->val_status & 0x0F);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/bitrev.h:102:21: note: expanded from macro 'bitrev8'
__constant_bitrev8(__x) : \
~~~~~~~~~~~~~~~~~~~^~~~
include/linux/bitrev.h:67:11: note: expanded from macro '__constant_bitrev8'
u8 __x = x; \
~~~ ^
Both the bitrev and the __constant_bitrev macros use an internal
variable named __x, which goes horribly wrong when passing one to the
other.
The obvious fix is to rename one of the variables, so this adds an extra
'_'.
It seems we got away with this because
- there are only a few drivers using bitrev macros
- usually there are no constant arguments to those
- when they are constant, they tend to be either 0 or (unsigned)-1
(drivers/isdn/i4l/isdnhdlc.o, drivers/iio/amplifiers/ad8366.c) and
give the correct result by pure chance.
In fact, the only driver that I could find that gets different results
with this is drivers/net/wan/slic_ds26522.c, which in turn is a driver
for fairly rare hardware (adding the maintainer to Cc for testing).
Link: http://lkml.kernel.org/r/20190322140503.123580-1-arnd@arndb.de Fixes: 556d2f055bf6 ("ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Cc: Zhao Qiang <qiang.zhao@nxp.com> Cc: Yalin Wang <yalin.wang@sonymobile.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kmemleak: powerpc: skip scanning holes in the .bss section
Commit 2d4f567103ff ("KVM: PPC: Introduce kvm_tmp framework") adds
kvm_tmp[] into the .bss section and then free the rest of unused spaces
back to the page allocator.
With DEBUG_PAGEALLOC=y, it will unmap those pages from kernel. As the
result, kmemleak scan will trigger a panic when it scans the .bss
section with unmapped pages.
This patch creates dedicated kmemleak objects for the .data, .bss and
potentially .data..ro_after_init sections to allow partial freeing via
the kmemleak_free_part() in the powerpc kvm_free_tmp() function.
Link: http://lkml.kernel.org/r/20190321171917.62049-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Qian Cai <cai@lca.pw> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Qian Cai <cai@lca.pw> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Avi Kivity <avi@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A recent optimization in Clang (r355672) lowers comparisons of the
return value of memcmp against zero to comparisons of the return value
of bcmp against zero. This helps some platforms that implement bcmp
more efficiently than memcmp. glibc simply aliases bcmp to memcmp, but
an optimized implementation is in the works.
This results in linkage failures for all targets with Clang due to the
undefined symbol. For now, just implement bcmp as a tailcail to memcmp
to unbreak the build. This routine can be further optimized in the
future.
Other ideas discussed:
* A weak alias was discussed, but breaks for architectures that define
their own implementations of memcmp since aliases to declarations are
not permitted (only definitions). Arch-specific memcmp
implementations typically declare memcmp in C headers, but implement
them in assembly.
* -ffreestanding also is used sporadically throughout the kernel.
* -fno-builtin-bcmp doesn't work when doing LTO.
Link: https://bugs.llvm.org/show_bug.cgi?id=41035 Link: https://code.woboq.org/userspace/glibc/string/memcmp.c.html#bcmp Link: https://github.com/llvm/llvm-project/commit/8e16d73346f8091461319a7dfc4ddd18eedcff13 Link: https://github.com/ClangBuiltLinux/linux/issues/416 Link: http://lkml.kernel.org/r/20190313211335.165605-1-ndesaulniers@google.com Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Reported-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Suggested-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: James Y Knight <jyknight@google.com> Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge tag 'for-5.1/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper fixes from Mike Snitzer:
- Two queue_limits stacking fixes: disable discards if underlying
driver does. And propagate BDI_CAP_STABLE_WRITES to fix sporadic
checksum errors.
- Fix that reverts a DM core limit that wasn't needed given that
dm-crypt was already updated to impose an equivalent limit.
- Fix dm-init to properly establish 'const' for __initconst array.
- Fix deadlock in DM integrity target that occurs when overlapping IO
is being issued to it. And two smaller fixes to the DM integrity
target.
* tag 'for-5.1/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm integrity: fix deadlock with overlapping I/O
dm: disable DISCARD if the underlying storage no longer supports it
dm table: propagate BDI_CAP_STABLE_WRITES to fix sporadic checksum errors
dm: revert 8f50e358153d ("dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE")
dm init: fix const confusion for dm_allowed_targets array
dm integrity: make dm_integrity_init and dm_integrity_exit static
dm integrity: change memcmp to strncmp in dm_integrity_ctr
Merge tag 'vfio-v5.1-rc4' of git://github.com/awilliam/linux-vfio
Pull VFIO fixes from Alex Williamson:
- Fix clang printk format errors (Louis Taylor)
- Declare structure static to fix sparse warning (Wang Hai)
- Limit user DMA mappings per container (CVE-2019-3882) (Alex
Williamson)
* tag 'vfio-v5.1-rc4' of git://github.com/awilliam/linux-vfio:
vfio/type1: Limit DMA mappings per container
vfio/spapr_tce: Make symbol 'tce_iommu_driver_ops' static
vfio/pci: use correct format characters
Merge tag 'trace-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull syscall-get-arguments cleanup and fixes from Steven Rostedt:
"Andy Lutomirski approached me to tell me that the
syscall_get_arguments() implementation in x86 was horrible and gcc
certainly gets it wrong.
He said that since the tracepoints only pass in 0 and 6 for i and n
repectively, it should be optimized for that case. Inspecting the
kernel, I discovered that all users pass in 0 for i and only one file
passing in something other than 6 for the number of arguments. That
code happens to be my own code used for the special syscall tracing.
That can easily be converted to just using 0 and 6 as well, and only
copying what is needed. Which is probably the faster path anyway for
that case.
Along the way, a couple of real fixes came from this as the
syscall_get_arguments() function was incorrect for csky and riscv.
x86 has been optimized to for the new interface that removes the
variable number of arguments, but the other architectures could still
use some loving and take more advantage of the simpler interface"
* tag 'trace-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
syscalls: Remove start and number from syscall_set_arguments() args
syscalls: Remove start and number from syscall_get_arguments() args
csky: Fix syscall_get_arguments() and syscall_set_arguments()
riscv: Fix syscall_get_arguments() and syscall_set_arguments()
tracing/syscalls: Pass in hardcoded 6 into syscall_get_arguments()
ptrace: Remove maxargs from task_current_syscall()
dm-integrity will deadlock if overlapping I/O is issued to it, the bug
was introduced by commit 724376a04d1a ("dm integrity: implement fair
range locks"). Users rarely use overlapping I/O so this bug went
undetected until now.
Fix this bug by correcting, likely cut-n-paste, typos in
ranges_overlap() and also remove a flawed ranges_overlap() check in
remove_range_unlocked(). This condition could leave unprocessed bios
hanging on wait_list forever.
Cc: stable@vger.kernel.org # v4.19+ Fixes: 724376a04d1a ("dm integrity: implement fair range locks") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Marc Orr [Tue, 2 Apr 2019 06:56:00 +0000 (23:56 -0700)]
KVM: x86: nVMX: fix x2APIC VTPR read intercept
Referring to the "VIRTUALIZING MSR-BASED APIC ACCESSES" chapter of the
SDM, when "virtualize x2APIC mode" is 1 and "APIC-register
virtualization" is 0, a RDMSR of 808H should return the VTPR from the
virtual APIC page.
However, for nested, KVM currently fails to disable the read intercept
for this MSR. This means that a RDMSR exit takes precedence over
"virtualize x2APIC mode", and KVM passes through L1's TPR to L2,
instead of sourcing the value from L2's virtual APIC page.
This patch fixes the issue by disabling the read intercept, in VMCS02,
for the VTPR when "APIC-register virtualization" is 0.
The issue described above and fix prescribed here, were verified with
a related patch in kvm-unit-tests titled "Test VMX's virtualize x2APIC
mode w/ nested".
Signed-off-by: Marc Orr <marcorr@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Fixes: c992384bde84f ("KVM: vmx: speed up MSR bitmap merge") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Marc Orr [Tue, 2 Apr 2019 06:55:59 +0000 (23:55 -0700)]
KVM: x86: nVMX: close leak of L0's x2APIC MSRs (CVE-2019-3887)
The nested_vmx_prepare_msr_bitmap() function doesn't directly guard the
x2APIC MSR intercepts with the "virtualize x2APIC mode" MSR. As a
result, we discovered the potential for a buggy or malicious L1 to get
access to L0's x2APIC MSRs, via an L2, as follows.
1. L1 executes WRMSR(IA32_SPEC_CTRL, 1). This causes the spec_ctrl
variable, in nested_vmx_prepare_msr_bitmap() to become true.
2. L1 disables "virtualize x2APIC mode" in VMCS12.
3. L1 enables "APIC-register virtualization" in VMCS12.
Now, KVM will set VMCS02's x2APIC MSR intercepts from VMCS12, and then
set "virtualize x2APIC mode" to 0 in VMCS02. Oops.
This patch closes the leak by explicitly guarding VMCS02's x2APIC MSR
intercepts with VMCS12's "virtualize x2APIC mode" control.
The scenario outlined above and fix prescribed here, were verified with
a related patch in kvm-unit-tests titled "Add leak scenario to
virt_x2apic_mode_test".
Note, it looks like this issue may have been introduced inadvertently
during a merge---see 15303ba5d1cd.
Signed-off-by: Marc Orr <marcorr@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>