commit 3ce120b16cc548472f80cf8644f90eda958cf1b6 upstream.
It appears that hardened gentoo enables "-fstack-check" by default for
gcc.
That doesn't work _at_all_ for the kernel, because the kernel stack
doesn't act like a user stack at all: it's much smaller, and it doesn't
auto-expand on use. So the extra "probe one page below the stack" code
generated by -fstack-check just breaks the kernel in horrible ways,
causing infinite double faults etc.
[ I have to say, that the particular code gcc generates looks very
stupid even for user space where it works, but that's a separate
issue. ]
Reported-and-tested-by: Alexander Tsoy <alexander@tsoy.me>
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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Merge upstream tag 'v3.10.84' into LA.BR.1.3.3
This merge brings us up-to-date as of upstream tag v3.10.84
* tag 'v3.10.84' (317 commits):
Linux 3.10.84
fs: Fix S_NOSEC handling
KVM: x86: make vapics_in_nmi_mode atomic
MIPS: Fix KVM guest fixmap address
x86/PCI: Use host bridge _CRS info on Foxconn K8M890-8237A
powerpc/perf: Fix book3s kernel to userspace backtraces
arm: KVM: force execution of HCPTR access on VM exit
Revert "crypto: talitos - convert to use be16_add_cpu()"
crypto: talitos - avoid memleak in talitos_alg_alloc()
sctp: Fix race between OOTB responce and route removal
packet: avoid out of bounds read in round robin fanout
packet: read num_members once in packet_rcv_fanout()
bridge: fix br_stp_set_bridge_priority race conditions
bridge: fix multicast router rlist endless loop
sparc: Use GFP_ATOMIC in ldc_alloc_exp_dring() as it can be called in softirq context
Linux 3.10.83
bus: mvebu: pass the coherency availability information at init time
KVM: nSVM: Check for NRIPS support before updating control field
ARM: clk-imx6q: refine sata's parent
d_walk() might skip too much
ipv6: update ip6_rt_last_gc every time GC is run
ipv6: prevent fib6_run_gc() contention
xfrm: Increase the garbage collector threshold
Btrfs: make xattr replace operations atomic
x86/microcode/intel: Guard against stack overflow in the loader
fs: take i_mutex during prepare_binprm for set[ug]id executables
hpsa: add missing pci_set_master in kdump path
hpsa: refine the pci enable/disable handling
sb_edac: Fix erroneous bytes->gigabytes conversion
ACPICA: Utilities: Cleanup to remove useless ACPI_PRINTF/FORMAT_xxx helpers.
ACPICA: Utilities: Cleanup to convert physical address printing formats.
__ptrace_may_access() should not deny sub-threads
include/linux/sched.h: don't use task->pid/tgid in same_thread_group/has_group_leader_pid
netfilter: Zero the tuple in nfnl_cthelper_parse_tuple()
netfilter: nfnetlink_cthelper: Remove 'const' and '&' to avoid warnings
config: Enable NEED_DMA_MAP_STATE by default when SWIOTLB is selected
get rid of s_files and files_lock
fput: turn "list_head delayed_fput_list" into llist_head
Linux 3.10.82
lpfc: Add iotag memory barrier
pipe: iovec: Fix memory corruption when retrying atomic copy as non-atomic
drm/mgag200: Reject non-character-cell-aligned mode widths
tracing: Have filter check for balanced ops
crypto: caam - fix RNG buffer cache alignment
Linux 3.10.81
btrfs: cleanup orphans while looking up default subvolume
btrfs: incorrect handling for fiemap_fill_next_extent return
cfg80211: wext: clear sinfo struct before calling driver
mm/memory_hotplug.c: set zone->wait_table to null after freeing it
drm/i915: Fix DDC probe for passive adapters
pata_octeon_cf: fix broken build
ozwpan: unchecked signed subtraction leads to DoS
ozwpan: divide-by-zero leading to panic
ozwpan: Use proper check to prevent heap overflow
MIPS: Fix enabling of DEBUG_STACKOVERFLOW
ring-buffer-benchmark: Fix the wrong sched_priority of producer
USB: serial: ftdi_sio: Add support for a Motion Tracker Development Board
USB: cp210x: add ID for HubZ dual ZigBee and Z-Wave dongle
block: fix ext_dev_lock lockdep report
Input: elantech - fix detection of touchpads where the revision matches a known rate
ALSA: usb-audio: add MAYA44 USB+ mixer control names
ALSA: usb-audio: Add mic volume fix quirk for Logitech Quickcam Fusion
ALSA: hda/realtek - Add a fixup for another Acer Aspire 9420
iio: adis16400: Compute the scan mask from channel indices
iio: adis16400: Use != channel indices for the two voltage channels
iio: adis16400: Report pressure channel scale
xen: netback: read hotplug script once at start of day.
udp: fix behavior of wrong checksums
net_sched: invoke ->attach() after setting dev->qdisc
unix/caif: sk_socket can disappear when state is unlocked
net: dp83640: fix broken calibration routine.
bridge: fix parsing of MLDv2 reports
ipv4: Avoid crashing in ip_error
net: phy: Allow EEE for all RGMII variants
Linux 3.10.80
fs/binfmt_elf.c:load_elf_binary(): return -EINVAL on zero-length mappings
vfs: read file_handle only once in handle_to_path
ACPI / init: Fix the ordering of acpi_reserve_resources()
Input: elantech - fix semi-mt protocol for v3 HW
rtlwifi: rtl8192cu: Fix kernel deadlock
md/raid5: don't record new size if resize_stripes fails.
svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures
ARM: fix missing syscall trace exit
ARM: dts: imx27: only map 4 Kbyte for fec registers
crypto: s390/ghash - Fix incorrect ghash icv buffer handling.
rt2x00: add new rt2800usb device DWA 130
libata: Ignore spurious PHY event on LPM policy change
libata: Add helper to determine when PHY events should be ignored
ext4: check for zero length extent explicitly
ext4: convert write_begin methods to stable_page_writes semantics
mmc: atmel-mci: fix bad variable type for clkdiv
powerpc: Align TOC to 256 bytes
usb: gadget: configfs: Fix interfaces array NULL-termination
usb-storage: Add NO_WP_DETECT quirk for Lacie 059f:0651 devices
USB: cp210x: add ID for KCF Technologies PRN device
USB: pl2303: Remove support for Samsung I330
USB: visor: Match I330 phone more precisely
xhci: gracefully handle xhci_irq dead device
xhci: Solve full event ring by increasing TRBS_PER_SEGMENT to 256
xhci: fix isoc endpoint dequeue from advancing too far on transaction error
target/pscsi: Don't leak scsi_host if hba is VIRTUAL_HOST
ASoC: wm8994: correct BCLK DIV 348 to 384
ASoC: wm8960: fix "RINPUT3" audio route error
ASoC: mc13783: Fix wrong mask value used in mc13xxx_reg_rmw() calls
ALSA: hda - Add headphone quirk for Lifebook E752
ALSA: hda - Add Conexant codecs CX20721, CX20722, CX20723 and CX20724
d_walk() might skip too much
lib: Fix strnlen_user() to not touch memory after specified maximum
hwmon: (ntc_thermistor) Ensure iio channel is of type IIO_VOLTAGE
libceph: request a new osdmap if lingering request maps to no osd
lguest: fix out-by-one error in address checking.
fs, omfs: add NULL terminator in the end up the token list
KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with shadow pages
net: socket: Fix the wrong returns for recvmsg and sendmsg
kernel: use the gnu89 standard explicitly
staging, rtl8192e, LLVMLinux: Remove unused inline prototype
staging: rtl8712, rtl8712: avoid lots of build warnings
staging, rtl8192e, LLVMLinux: Change extern inline to static inline
drm/i915: Fix declaration of intel_gmbus_{is_forced_bit/is_port_falid}
staging: wlags49_h2: fix extern inline functions
Linux 3.10.79
ACPICA: Utilities: Cleanup to enforce ACPI_PHYSADDR_TO_PTR()/ACPI_PTR_TO_PHYSADDR().
ACPICA: Tables: Change acpi_find_root_pointer() to use acpi_physical_address.
revert "softirq: Add support for triggering softirq work on softirqs"
sound/oss: fix deadlock in sequencer_ioctl(SNDCTL_SEQ_OUTOFBAND)
mmc: card: Don't access RPMB partitions for normal read/write
pinctrl: Don't just pretend to protect pinctrl_maps, do it for real
drm/i915: Add missing MacBook Pro models with dual channel LVDS
ARM: mvebu: armada-xp-openblocks-ax3-4: Disable internal RTC
ARM: dts: imx23-olinuxino: Fix dr_mode of usb0
ARM: dts: imx28: Fix AUART4 TX-DMA interrupt name
ARM: dts: imx25: Add #pwm-cells to pwm4
gpio: sysfs: fix memory leaks and device hotplug
gpio: unregister gpiochip device before removing it
xen/console: Update console event channel on resume
mm/memory-failure: call shake_page() when error hits thp tail page
nilfs2: fix sanity check of btree level in nilfs_btree_root_broken()
ocfs2: dlm: fix race between purge and get lock resource
Linux 3.10.78
ARC: signal handling robustify
UBI: fix soft lockup in ubi_check_volume()
Drivers: hv: vmbus: Don't wait after requesting offers
ARM: dts: dove: Fix uart[23] reg property
staging: panel: fix lcd type
usb: gadget: printer: enqueue printer's response for setup request
usb: host: oxu210hp: use new USB_RESUME_TIMEOUT
3w-sas: fix command completion race
3w-9xxx: fix command completion race
3w-xxxx: fix command completion race
ext4: fix data corruption caused by unwritten and delayed extents
rbd: end I/O the entire obj_request on error
serial: of-serial: Remove device_type = "serial" registration
ALSA: hda - Fix mute-LED fixed mode
ALSA: emu10k1: Emu10k2 32 bit DMA mode
ALSA: emu10k1: Fix card shortname string buffer overflow
ALSA: emux: Fix mutex deadlock in OSS emulation
ALSA: emux: Fix mutex deadlock at unloading
ipv4: Missing sk_nulls_node_init() in ping_unhash().
Linux 3.10.77
s390: Fix build error
nosave: consolidate __nosave_{begin,end} in <asm/sections.h>
memstick: mspro_block: add missing curly braces
C6x: time: Ensure consistency in __init
wl18xx: show rx_frames_per_rates as an array as it really is
lib: memzero_explicit: use barrier instead of OPTIMIZER_HIDE_VAR
e1000: add dummy allocator to fix race condition between mtu change and netpoll
ksoftirqd: Enable IRQs and call cond_resched() before poking RCU
RCU pathwalk breakage when running into a symlink overmounting something
drm/i915: cope with large i2c transfers
drm/radeon: fix doublescan modes (v2)
i2c: core: Export bus recovery functions
IB/mlx4: Fix WQE LSO segment calculation
IB/core: don't disallow registering region starting at 0x0
IB/core: disallow registering 0-sized memory region
stk1160: Make sure current buffer is released
mvsas: fix panic on expander attached SATA devices
Drivers: hv: vmbus: Fix a bug in the error path in vmbus_open()
xtensa: provide __NR_sync_file_range2 instead of __NR_sync_file_range
xtensa: xtfpga: fix hardware lockup caused by LCD driver
ACPICA: Utilities: split IO address types from data type models.
drivers: parport: Kconfig: exclude arm64 for PARPORT_PC
scsi: storvsc: Fix a bug in copy_from_bounce_buffer()
UBI: fix check for "too many bytes"
UBI: initialize LEB number variable
UBI: fix out of bounds write
UBI: account for bitflips in both the VID header and data
tools/power turbostat: Use $(CURDIR) instead of $(PWD) and add support for O= option in Makefile
powerpc/perf: Cap 64bit userspace backtraces to PERF_MAX_STACK_DEPTH
ext4: make fsync to sync parent dir in no-journal for real this time
arm64: kernel: compiling issue, need delete read_current_timer()
video: vgacon: Don't build on arm64
console: Disable VGA text console support on cris
drivers: parport: Kconfig: exclude h8300 for PARPORT_PC
parport: disable PC-style parallel port support on cris
rtlwifi: rtl8192cu: Add new device ID
rtlwifi: rtl8192cu: Add new USB ID
ptrace: fix race between ptrace_resume() and wait_task_stopped()
fs/binfmt_elf.c: fix bug in loading of PIE binaries
Input: elantech - fix absolute mode setting on some ASUS laptops
ALSA: emu10k1: don't deadlock in proc-functions
usb: core: hub: use new USB_RESUME_TIMEOUT
usb: host: sl811: use new USB_RESUME_TIMEOUT
usb: host: xhci: use new USB_RESUME_TIMEOUT
usb: host: isp116x: use new USB_RESUME_TIMEOUT
usb: host: r8a66597: use new USB_RESUME_TIMEOUT
usb: define a generic USB_RESUME_TIMEOUT macro
usb: phy: Find the right match in devm_usb_phy_match
ARM: S3C64XX: Use fixed IRQ bases to avoid conflicts on Cragganmore
ARM: 8320/1: fix integer overflow in ELF_ET_DYN_BASE
power_supply: lp8788-charger: Fix leaked power supply on probe fail
ring-buffer: Replace this_cpu_*() with __this_cpu_*()
spi: spidev: fix possible arithmetic overflow for multi-transfer message
cdc-wdm: fix endianness bug in debug statements
MIPS: Hibernate: flush TLB entries earlier
KVM: use slowpath for cross page cached accesses
s390/hibernate: fix save and restore of kernel text section
KVM: s390: Zero out current VMDB of STSI before including level3 data.
usb: gadget: composite: enable BESL support
Btrfs: fix inode eviction infinite loop after cloning into it
Btrfs: fix log tree corruption when fs mounted with -o discard
tcp: avoid looping in tcp_send_fin()
tcp: fix possible deadlock in tcp_send_fin()
ip_forward: Drop frames with attached skb->sk
Linux 3.10.76
dcache: Fix locking bugs in backported "deal with deadlock in d_walk()"
arc: mm: Fix build failure
sb_edac: avoid INTERNAL ERROR message in EDAC with unspecified channel
x86: mm: move mmap_sem unlock from mm_fault_error() to caller
vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than SIGBUS
vm: add VM_FAULT_SIGSEGV handling support
deal with deadlock in d_walk()
move d_rcu from overlapping d_child to overlapping d_alias
kconfig: Fix warning "‘jump’ may be used uninitialized"
KVM: x86: SYSENTER emulation is broken
netfilter: conntrack: disable generic tracking for known protocols
Bluetooth: Ignore isochronous endpoints for Intel USB bootloader
Bluetooth: Add support for Intel bootloader devices
Bluetooth: btusb: Add IMC Networks (Broadcom based)
Bluetooth: Add firmware update for Atheros 0cf3:311f
Bluetooth: Enable Atheros 0cf3:311e for firmware upload
mm: Fix NULL pointer dereference in madvise(MADV_WILLNEED) support
splice: Apply generic position and size checks to each write
jfs: fix readdir regression
serial: 8250_dw: Fix deadlock in LCR workaround
benet: Call dev_kfree_skby_any instead of kfree_skb.
ixgb: Call dev_kfree_skby_any instead of dev_kfree_skb.
tg3: Call dev_kfree_skby_any instead of dev_kfree_skb.
bnx2: Call dev_kfree_skby_any instead of dev_kfree_skb.
r8169: Call dev_kfree_skby_any instead of dev_kfree_skb.
8139too: Call dev_kfree_skby_any instead of dev_kfree_skb.
8139cp: Call dev_kfree_skby_any instead of kfree_skb.
tcp: tcp_make_synack() should clear skb->tstamp
tcp: fix FRTO undo on cumulative ACK of SACKed range
ipv6: Don't reduce hop limit for an interface
tcp: prevent fetching dst twice in early demux code
remove extra definitions of U32_MAX
conditionally define U32_MAX
Linux 3.10.75
pagemap: do not leak physical addresses to non-privileged userspace
console: Fix console name size mismatch
IB/mlx4: Saturate RoCE port PMA counters in case of overflow
kernel.h: define u8, s8, u32, etc. limits
net: llc: use correct size for sysctl timeout entries
net: rds: use correct size for max unacked packets and bytes
ipc: fix compat msgrcv with negative msgtyp
core, nfqueue, openvswitch: fix compilation warning
media: s5p-mfc: fix mmap support for 64bit arch
iscsi target: fix oops when adding reject pdu
ocfs2: _really_ sync the right range
be2iscsi: Fix kernel panic when device initialization fails
cifs: fix use-after-free bug in find_writable_file
usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers
cpuidle: ACPI: do not overwrite name and description of C0
dmaengine: omap-dma: Fix memory leak when terminating running transfer
iio: imu: Use iio_trigger_get for indio_dev->trig assignment
iio: inv_mpu6050: Clear timestamps fifo while resetting hardware fifo
Defer processing of REQ_PREEMPT requests for blocked devices
USB: ftdi_sio: Use jtag quirk for SNAP Connect E10
USB: ftdi_sio: Added custom PID for Synapse Wireless product
radeon: Do not directly dereference pointers to BIOS area.
writeback: fix possible underflow in write bandwidth calculation
writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth()
mm/memory hotplug: postpone the reset of obsolete pgdat
nbd: fix possible memory leak
iwlwifi: dvm: run INIT firmware again upon .start()
IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic
IB/core: Avoid leakage from kernel to user space
tcp: Fix crash in TCP Fast Open
selinux: fix sel_write_enforce broken return value
ALSA: hda - Fix headphone pin config for Lifebook T731
ALSA: usb - Creative USB X-Fi Pro SB1095 volume knob support
ALSA: hda - Add one more node in the EAPD supporting candidate list
Linux 3.10.74
net: ethernet: pcnet32: Setup the SRAM and NOUFLO on Am79C97{3, 5}
powerpc/mpc85xx: Add ranges to etsec2 nodes
hfsplus: fix B-tree corruption after insertion at position 0
dm: hold suspend_lock while suspending device during device deletion
vt6655: RFbSetPower fix missing rate RATE_12M
perf: Fix irq_work 'tail' recursion
Revert "iwlwifi: mvm: fix failure path when power_update fails in add_interface"
mac80211: drop unencrypted frames in mesh fwding
mac80211: disable u-APSD queues by default
nl80211: ignore HT/VHT capabilities without QoS/WMM
tcm_qla2xxx: Fix incorrect use of __transport_register_session
tcm_fc: missing curly braces in ft_invl_hw_context()
ASoC: wm8955: Fix wrong value references for boolean kctl
ASoC: adav80x: Fix wrong value references for boolean kctl
ASoC: ak4641: Fix wrong value references for boolean kctl
ASoC: wm8904: Fix wrong value references for boolean kctl
ASoC: wm8903: Fix wrong value references for boolean kctl
ASoC: wm2000: Fix wrong value references for boolean kctl
ASoC: wm8731: Fix wrong value references for boolean kctl
ASoC: tas5086: Fix wrong value references for boolean kctl
ASoC: wm8960: Fix wrong value references for boolean kctl
ASoC: cs4271: Fix wrong value references for boolean kctl
ASoC: sgtl5000: remove useless register write clearing CHRGPUMP_POWERUP
Change-Id: Ib7976ee2c7224e39074157e28db4158db40b00db
Signed-off-by: Kaushal Kumar <kaushalk@codeaurora.org>
Current button press detection method is relying on button
press interrupt with a wait event insdie mechanical insertion
handler. However, though Codec hardware raises button press
interrupt status bit, the handler will not get invoked because
mechanical insertion interrupt handler does not return
IRQ_HANDLED. So the wait-event always gets timedout assuming
that there is no button press interrupt. This would cause delayed
button press detection and it will result into HEADSET detection
first followed by HEADPHONE when a valid 3-pole headphone cable
is inserted into the headset jack. Move the wait-event outside
the interrupt context to a workqueue to handle the button press
interrupts properly.
Change-Id: I49b71c2d326f45b7be91b7d470f60c487e69dedc
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>
commit 51b97e354ba9fce1890cf38ecc754aa49677fc89 upstream.
Sasha Levin reports:
"gcc5 changes the default standard to c11, which makes kernel build
unhappy
Explicitly define the kernel standard to be gnu89 which should keep
everything working exactly like it was before gcc5"
There are multiple small issues with the new default, but the biggest
issue seems to be that the old - and very useful - GNU extension to
allow a cast in front of an initializer has gone away.
Patch updated by Kirill:
"I'm pretty sure all gcc versions you can build kernel with supports
-std=gnu89. cc-option is redunrant.
We also need to adjust HOSTCFLAGS otherwise allmodconfig fails for me"
Note by Andrew Pinski:
"Yes it was reported and both problems relating to this extension has
been added to gnu99 and gnu11. Though there are other issues with the
kernel dealing with extern inline have different semantics between
gnu89 and gnu99/11"
End result: we may be able to move up to a newer stdc model eventually,
but right now the newer models have some annoying deficiencies, so the
traditional "gnu89" model ends up being the preferred one.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Singed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kernel Address sanitizer (KASan) is a dynamic memory error detector. It
provides fast and comprehensive solution for finding use-after-free and
out-of-bounds bugs.
KASAN uses compile-time instrumentation for checking every memory access,
therefore GCC > v4.9.2 required. v4.9.2 almost works, but has issues with
putting symbol aliases into the wrong section, which breaks kasan
instrumentation of globals.
This patch only adds infrastructure for kernel address sanitizer. It's
not available for use yet. The idea and some code was borrowed from [1].
Basic idea:
The main idea of KASAN is to use shadow memory to record whether each byte
of memory is safe to access or not, and use compiler's instrumentation to
check the shadow memory on each memory access.
Address sanitizer uses 1/8 of the memory addressable in kernel for shadow
memory and uses direct mapping with a scale and offset to translate a
memory address to its corresponding shadow address.
Here is function to translate address to corresponding shadow address:
unsigned long kasan_mem_to_shadow(unsigned long addr)
{
return (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET;
}
where KASAN_SHADOW_SCALE_SHIFT = 3.
So for every 8 bytes there is one corresponding byte of shadow memory.
The following encoding used for each shadow byte: 0 means that all 8 bytes
of the corresponding memory region are valid for access; k (1 <= k <= 7)
means that the first k bytes are valid for access, and other (8 - k) bytes
are not; Any negative value indicates that the entire 8-bytes are
inaccessible. Different negative values used to distinguish between
different kinds of inaccessible memory (redzones, freed memory) (see
mm/kasan/kasan.h).
To be able to detect accesses to bad memory we need a special compiler.
Such compiler inserts a specific function calls (__asan_load*(addr),
__asan_store*(addr)) before each memory access of size 1, 2, 4, 8 or 16.
These functions check whether memory region is valid to access or not by
checking corresponding shadow memory. If access is not valid an error
printed.
Historical background of the address sanitizer from Dmitry Vyukov:
"We've developed the set of tools, AddressSanitizer (Asan),
ThreadSanitizer and MemorySanitizer, for user space. We actively use
them for testing inside of Google (continuous testing, fuzzing,
running prod services). To date the tools have found more than 10'000
scary bugs in Chromium, Google internal codebase and various
open-source projects (Firefox, OpenSSL, gcc, clang, ffmpeg, MySQL and
lots of others): [2] [3] [4].
The tools are part of both gcc and clang compilers.
We have not yet done massive testing under the Kernel AddressSanitizer
(it's kind of chicken and egg problem, you need it to be upstream to
start applying it extensively). To date it has found about 50 bugs.
Bugs that we've found in upstream kernel are listed in [5].
We've also found ~20 bugs in out internal version of the kernel. Also
people from Samsung and Oracle have found some.
[...]
As others noted, the main feature of AddressSanitizer is its
performance due to inline compiler instrumentation and simple linear
shadow memory. User-space Asan has ~2x slowdown on computational
programs and ~2x memory consumption increase. Taking into account that
kernel usually consumes only small fraction of CPU and memory when
running real user-space programs, I would expect that kernel Asan will
have ~10-30% slowdown and similar memory consumption increase (when we
finish all tuning).
I agree that Asan can well replace kmemcheck. We have plans to start
working on Kernel MemorySanitizer that finds uses of unitialized
memory. Asan+Msan will provide feature-parity with kmemcheck. As
others noted, Asan will unlikely replace debug slab and pagealloc that
can be enabled at runtime. Asan uses compiler instrumentation, so even
if it is disabled, it still incurs visible overheads.
Asan technology is easily portable to other architectures. Compiler
instrumentation is fully portable. Runtime has some arch-dependent
parts like shadow mapping and atomic operation interception. They are
relatively easy to port."
Comparison with other debugging features:
========================================
KMEMCHECK:
- KASan can do almost everything that kmemcheck can. KASan uses
compile-time instrumentation, which makes it significantly faster than
kmemcheck. The only advantage of kmemcheck over KASan is detection of
uninitialized memory reads.
Some brief performance testing showed that kasan could be
x500-x600 times faster than kmemcheck:
$ netperf -l 30
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost (127.0.0.1) port 0 AF_INET
Recv Send Send
Socket Socket Message Elapsed
Size Size Size Time Throughput
bytes bytes bytes secs. 10^6bits/sec
no debug: 87380 16384 16384 30.00 41624.72
kasan inline: 87380 16384 16384 30.00 12870.54
kasan outline: 87380 16384 16384 30.00 10586.39
kmemcheck: 87380 16384 16384 30.03 20.23
- Also kmemcheck couldn't work on several CPUs. It always sets
number of CPUs to 1. KASan doesn't have such limitation.
DEBUG_PAGEALLOC:
- KASan is slower than DEBUG_PAGEALLOC, but KASan works on sub-page
granularity level, so it able to find more bugs.
SLUB_DEBUG (poisoning, redzones):
- SLUB_DEBUG has lower overhead than KASan.
- SLUB_DEBUG in most cases are not able to detect bad reads,
KASan able to detect both reads and writes.
- In some cases (e.g. redzone overwritten) SLUB_DEBUG detect
bugs only on allocation/freeing of object. KASan catch
bugs right before it will happen, so we always know exact
place of first bad read/write.
[1] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
[2] https://code.google.com/p/address-sanitizer/wiki/FoundBugs
[3] https://code.google.com/p/thread-sanitizer/wiki/FoundBugs
[4] https://code.google.com/p/memory-sanitizer/wiki/FoundBugs
[5] https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel#Trophies
Based on work by Andrey Konovalov.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Cc: Yuri Gribov <tetra2005@gmail.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[tsoni@codeaurora.org: trivial merge conflicts]
Git-commit: 0b24becc810dc3be6e3f94103a866f214c282394
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Change-Id: If62dffc8bb54d92654f221f5b365ed3f1a07fd3a
Signed-off-by: David Keitel <dkeitel@codeaurora.org>
Linus Torvalds
Willy Tarreau
Luca Stefani
LuK1337
Greg Kroah-Hartman
Kaushal Kumar
Phani Kumar Uppalapati
Kirill A. Shutemov
Andrey Ryabinin
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