Pull x86 spectre fixes from Borislav Petkov:
- Mitigate Spectre v2-type Branch History Buffer attacks on machines
which support eIBRS, i.e., the hardware-assisted speculation
restriction after it has been shown that such machines are vulnerable
even with the hardware mitigation.
- Do not use the default LFENCE-based Spectre v2 mitigation on AMD as
it is insufficient to mitigate such attacks. Instead, switch to
retpolines on all AMD by default.
- Update the docs and add some warnings for the obviously vulnerable
cmdline configurations.
* tag 'x86_bugs_for_v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT
x86/speculation: Warn about Spectre v2 LFENCE mitigation
x86/speculation: Update link to AMD speculation whitepaper
x86/speculation: Use generic retpoline by default on AMD
x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting
Documentation/hw-vuln: Update spectre doc
x86/speculation: Add eIBRS + Retpoline options
x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE
The following warning may appear while setting a CPU down:
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #20!!!
The IRQ_POLL_SOFTIRQ vector can be raised during the hotplug cpu_down()
path after ksoftirqd is parked and before the CPU actually dies. However
this is handled afterward at the CPUHP_IRQ_POLL_DEAD stage where the
queue gets migrated.
Hence this warning can be considered spurious and the vector can join
the "hotplug-safe" list.
Reported-and-tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
RCU_SOFTIRQ used to be special in that it could be raised on purpose
within the idle path to prevent from stopping the tick. Some code still
prevents from unnecessary warnings related to this specific behaviour
while entering in dynticks-idle mode.
However the nohz layout has changed quite a bit in ten years, and the
removal of CONFIG_RCU_FAST_NO_HZ has been the final straw to this
safe-conduct. Now the RCU_SOFTIRQ vector is expected to be raised from
sane places.
A remaining corner case is admitted though when the vector is invoked
in fragile hotplug path.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Hardware specific features may be able to calculate a crc64, so provide
a framework for drivers to register their implementation. If nothing is
registered, fallback to the generic table lookup implementation. The
implementation is modeled after the crct10dif equivalent.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20220303201312.3255347-7-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The NVM Express specification extended data integrity fields to 64 bits
using the Rocksoft parameters. Add the poly to the crc64 table
generation, and provide a generic library routine implementing the
algorithm.
The Rocksoft 64-bit CRC model parameters are as follows:
Poly: 0xAD93D23594C93659
Initial value: 0xFFFFFFFFFFFFFFFF
Reflected Input: True
Reflected Output: True
Xor Final: 0xFFFFFFFFFFFFFFFF
Since this model used reflected bits, the implementation generates the
reflected table so the result is ordered consistently.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220303201312.3255347-6-kbusch@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* for-5.18/drivers: (51 commits)
bcache: fixup multiple threads crash
bcache: fixup bcache_dev_sectors_dirty_add() multithreaded CPU false sharing
floppy: use memcpy_{to,from}_bvec
drbd: use bvec_kmap_local in recv_dless_read
drbd: use bvec_kmap_local in drbd_csum_bio
bcache: use bvec_kmap_local in bio_csum
nvdimm-btt: use bvec_kmap_local in btt_rw_integrity
nvdimm-blk: use bvec_kmap_local in nd_blk_rw_integrity
zram: use memcpy_from_bvec in zram_bvec_write
zram: use memcpy_to_bvec in zram_bvec_read
aoe: use bvec_kmap_local in bvcpy
iss-simdisk: use bvec_kmap_local in simdisk_submit_bio
nvme: check that EUI/GUID/UUID are globally unique
nvme: check for duplicate identifiers earlier
nvme: fix the check for duplicate unique identifiers
nvme: cleanup __nvme_check_ids
nvme: remove nssa from struct nvme_ctrl
nvme: explicitly set non-error for directives
nvme: expose cntrltype and dctype through sysfs
nvme: send uevent on connection up
...
Pull virtio fixes from Michael Tsirkin:
"Some last minute fixes that took a while to get ready. Not
regressions, but they look safe and seem to be worth to have"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
tools/virtio: handle fallout from folio work
tools/virtio: fix virtio_test execution
vhost: remove avail_event arg from vhost_update_avail_event()
virtio: drop default for virtio-mem
vdpa: fix use-after-free on vp_vdpa_remove
virtio-blk: Remove BUG_ON() in virtio_queue_rq()
virtio-blk: Don't use MAX_DISCARD_SEGMENTS if max_discard_seg is zero
vhost: fix hung thread due to erroneous iotlb entries
vduse: Fix returning wrong type in vduse_domain_alloc_iova()
vdpa/mlx5: add validation for VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command
vdpa/mlx5: should verify CTRL_VQ feature exists for MQ
vdpa: factor out vdpa_set_features_unlocked for vdpa internal use
virtio_console: break out of buf poll on remove
virtio: document virtio_reset_device
virtio: acknowledge all features before access
virtio: unexport virtio_finalize_features
Unfortunately, we ended up merging an old version of the patch "fix info
leak with DMA_FROM_DEVICE" instead of merging the latest one. Christoph
(the swiotlb maintainer), he asked me to create an incremental fix
(after I have pointed this out the mix up, and asked him for guidance).
So here we go.
The main differences between what we got and what was agreed are:
* swiotlb_sync_single_for_device is also required to do an extra bounce
* We decided not to introduce DMA_ATTR_OVERWRITE until we have exploiters
* The implantation of DMA_ATTR_OVERWRITE is flawed: DMA_ATTR_OVERWRITE
must take precedence over DMA_ATTR_SKIP_CPU_SYNC
Thus this patch removes DMA_ATTR_OVERWRITE, and makes
swiotlb_sync_single_for_device() bounce unconditionally (that is, also
when dir == DMA_TO_DEVICE) in order do avoid synchronising back stale
data from the swiotlb buffer.
Let me note, that if the size used with dma_sync_* API is less than the
size used with dma_[un]map_*, under certain circumstances we may still
end up with swiotlb not being transparent. In that sense, this is no
perfect fix either.
To get this bullet proof, we would have to bounce the entire
mapping/bounce buffer. For that we would have to figure out the starting
address, and the size of the mapping in
swiotlb_sync_single_for_device(). While this does seem possible, there
seems to be no firm consensus on how things are supposed to work.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: ddbd89deb7 ("swiotlb: fix info leak with DMA_FROM_DEVICE")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With FEAT_ECV and the 1GHz counter, it is pretty likely that the
event stream divider doesn't fit in the field that holds the
divider value (we only have 4 bits to describe counter bits [15:0]
Thankfully, FEAT_ECV also provides a scaling mechanism to switch
the field to cover counter bits [23:8] instead.
Enable this on arm64 when ECV is available (32bit doesn't have
any detection infrastructure and is unlikely to be run on an
ARMv8.6 system anyway).
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220203170502.2694422-1-maz@kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
nv12m_8l128 is 8-bit tiled nv12 format used by amphion decoder.
nv12m_10be_8l128 is 10-bit tiled format used by amphion decoder.
The tile size is 8x128
Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Shijie Qin <shijie.qin@nxp.com>
Signed-off-by: Zhou Peng <eagle.zhou@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Even yet more V4L2 patches for 5.18
* tag 'for-5.18-2.6-signed' of git://linuxtv.org/sailus/media_tree:
media: i2c: Fix pixel array positions in ov8865
media: adv7183: Convert to GPIO descriptors
media: m5mols: Convert to use GPIO descriptors
media: noon010p30: Convert to use GPIO descriptors
media: mt9m111: Drop unused include
media: adv7511: Drop unused include
media: i2c: isl7998x: Add driver for Intersil ISL7998x
media: dt-bindings: Add Intersil ISL79987 DT bindings
media: media-entity: Clarify media_entity_cleanup() usage
media: i2c: imx274: Drop surplus includes
media: i2c: ccs: Drop unused include
v4l: fwnode: Remove now-redundant loop from v4l2_fwnode_parse_reference()
v4l: fwnode: Drop redunant -ENODATA check in property reference parsing
media: media-entity: Simplify media_pipeline_start()
media: media-entity: Add media_pad_is_streaming() helper function
media: Add a driver for the og01a1b camera sensor
media: i2c: ov5648: Fix lockdep error
media: ov5640: Fix set format, v4l2_mbus_pixelcode not updated
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
There is no hardware which can filter input on the duty cycle, so no
driver implements this. On top of that, LIRC_CAN_SET_REC_DUTY_CYCLE
has the same value as LIRC_CAN_MEASURE_CARRIER (0x02000000).
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This adds support for the MediaTek MT6366 PMIC. This is a
multifunction device with the following sub modules:
- Regulator
- RTC
- Codec
- Interrupt
It is interfaced to the host controller using SPI interface
by a proprietary hardware called PMIC wrapper or pwrap.
MT6366 MFD is a child device of the pwrap.
Signed-off-by: Johnson Wang <johnson.wang@mediatek.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220106065407.16036-2-johnson.wang@mediatek.com
Some audio hardware cannot support the same slot width for all sample
widths, or a slot width equal to the sample width for all sample widths.
This is usually due either to limitations of the audio serial port or
system clocking restrictions.
A typical example would be:
- 16-bit samples in 16-bit slots
- 24-bit samples in 32-bit slots
The new dai-tdm-slot-width-map property allows setting a mapping of
sample widths and the corresponding tdm slot widths and slot counts.
Although the slot count is usually the same for all cases this does
allow for adding padding slots to maintain the same bitclk frequency.
The property is added to each endpoint node that needs the component
DAI to be told the TDM slot width and count.
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220228172754.453783-3-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The esp tunnel GSO handlers use skb_mac_gso_segment to
push the inner packet to the segmentation handlers.
However, skb_mac_gso_segment takes the Ethernet Protocol
ID from 'skb->protocol' which is wrong for inter address
family tunnels. We fix this by introducing a new
skb_eth_gso_segment function.
This function can be used if it is necessary to pass the
Ethernet Protocol ID directly to the segmentation handler.
First users of this function will be the esp4 and esp6
tunnel segmentation handlers.
Fixes: c35fe4106b ("xfrm: Add mode handlers for IPsec on layer 2")
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
The maximum message size that can be send is bigger than
the maximum site that skb_page_frag_refill can allocate.
So it is possible to write beyond the allocated buffer.
Fix this by doing a fallback to COW in that case.
v2:
Avoid get get_order() costs as suggested by Linus Torvalds.
Fixes: cac2661c53 ("esp4: Avoid skb_cow_data whenever possible")
Fixes: 03e2a30f6a ("esp6: Avoid skb_cow_data whenever possible")
Reported-by: valis <sec@valis.email>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Remove netif_rx_any_context and netif_rx_ni() because there are no more
users in tree.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
PHY drivers such as micrel or dp83640 need to analyze whether a given
skb is a PTP sync message for one step functionality.
In order to avoid code duplication introduce a generic function and
move it to ptp classify.
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add new V4L2_H264_DECODE_PARAM_FLAG_P/BFRAME flags that are needed by
NVIDIA Tegra video decoder. Userspace will have to set these flags in
accordance to the type of a decoded frame.
Reviewed-by: Nicolas Dufresne <nicolas@collabora.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
gnttab_end_foreign_access() is used to free a grant reference and
optionally to free the associated page. In case the grant is still in
use by the other side processing is being deferred. This leads to a
problem in case no page to be freed is specified by the caller: the
caller doesn't know that the page is still mapped by the other side
and thus should not be used for other purposes.
The correct way to handle this situation is to take an additional
reference to the granted page in case handling is being deferred and
to drop that reference when the grant reference could be freed
finally.
This requires that there are no users of gnttab_end_foreign_access()
left directly repurposing the granted page after the call, as this
might result in clobbered data or information leaks via the not yet
freed grant reference.
This is part of CVE-2022-23041 / XSA-396.
Reported-by: Simon Gaiser <simon@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
V4:
- expand comment in header
V5:
- get page ref in case of kmalloc() failure, too
Remove gnttab_query_foreign_access(), as it is unused and unsafe to
use.
All previous use cases assumed a grant would not be in use after
gnttab_query_foreign_access() returned 0. This information is useless
in best case, as it only refers to a situation in the past, which could
have changed already.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Add a new grant table function gnttab_try_end_foreign_access(), which
will remove and free a grant if it is not in use.
Its main use case is to either free a grant if it is no longer in use,
or to take some other action if it is still in use. This other action
can be an error exit, or (e.g. in the case of blkfront persistent grant
feature) some special handling.
This is CVE-2022-23036, CVE-2022-23038 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
V2:
- new patch
V4:
- add comments to header (Jan Beulich)
The TUN can be used as vhost-net backend. E.g, the tun_net_xmit() is the
interface to forward the skb from TUN to vhost-net/virtio-net.
However, there are many "goto drop" in the TUN driver. Therefore, the
kfree_skb_reason() is involved at each "goto drop" to help userspace
ftrace/ebpf to track the reason for the loss of packets.
The below reasons are introduced:
- SKB_DROP_REASON_DEV_READY
- SKB_DROP_REASON_NOMEM
- SKB_DROP_REASON_HDR_TRUNC
- SKB_DROP_REASON_TAP_FILTER
- SKB_DROP_REASON_TAP_TXFILTER
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The TAP can be used as vhost-net backend. E.g., the tap_handle_frame() is
the interface to forward the skb from TAP to vhost-net/virtio-net.
However, there are many "goto drop" in the TAP driver. Therefore, the
kfree_skb_reason() is involved at each "goto drop" to help userspace
ftrace/ebpf to track the reason for the loss of packets.
The below reasons are introduced:
- SKB_DROP_REASON_SKB_CSUM
- SKB_DROP_REASON_SKB_GSO_SEG
- SKB_DROP_REASON_SKB_UCOPY_FAULT
- SKB_DROP_REASON_DEV_HDR
- SKB_DROP_REASON_FULL_RING
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the introduction of the btf_type_tag "percpu", we can add a
MEM_PERCPU to identify those pointers that point to percpu memory.
The ability of differetiating percpu pointers from regular memory
pointers have two benefits:
1. It forbids unexpected use of percpu pointers, such as direct loads.
In kernel, there are special functions used for accessing percpu
memory. Directly loading percpu memory is meaningless. We already
have BPF helpers like bpf_per_cpu_ptr() and bpf_this_cpu_ptr() that
wrap the kernel percpu functions. So we can now convert percpu
pointers into regular pointers in a safe way.
2. Previously, bpf_per_cpu_ptr() and bpf_this_cpu_ptr() only work on
PTR_TO_PERCPU_BTF_ID, a special reg_type which describes static
percpu variables in kernel (we rely on pahole to encode them into
vmlinux BTF). Now, since we can identify __percpu tagged pointers,
we can also identify dynamically allocated percpu memory as well.
It means we can use bpf_xxx_cpu_ptr() on dynamic percpu memory.
This would be very convenient when accessing fields like
"cgroup->rstat_cpu".
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-4-haoluo@google.com
This is similar to commit 7472d5a642 ("compiler_types: define __user as
__attribute__((btf_type_tag("user")))"), where a type tag "user" was
introduced to identify the pointers that point to user memory. With that
change, the newest compile toolchain can encode __user information into
vmlinux BTF, which can be used by the BPF verifier to enforce safe
program behaviors.
Similarly, we have __percpu attribute, which is mainly used to indicate
memory is allocated in percpu region. The __percpu pointers in kernel
are supposed to be used together with functions like per_cpu_ptr() and
this_cpu_ptr(), which perform necessary calculation on the pointer's
base address. Without the btf_type_tag introduced in this patch,
__percpu pointers will be treated as regular memory pointers in vmlinux
BTF and BPF programs are allowed to directly dereference them, generating
incorrect behaviors. Now with "percpu" btf_type_tag, the BPF verifier is
able to differentiate __percpu pointers from regular pointers and forbids
unexpected behaviors like direct load.
The following is an example similar to the one given in commit
7472d5a642:
[$ ~] cat test.c
#define __percpu __attribute__((btf_type_tag("percpu")))
int foo(int __percpu *arg) {
return *arg;
}
[$ ~] clang -O2 -g -c test.c
[$ ~] pahole -JV test.o
...
File test.o:
[1] INT int size=4 nr_bits=32 encoding=SIGNED
[2] TYPE_TAG percpu type_id=1
[3] PTR (anon) type_id=2
[4] FUNC_PROTO (anon) return=1 args=(3 arg)
[5] FUNC foo type_id=4
[$ ~]
for the function argument "int __percpu *arg", its type is described as
PTR -> TYPE_TAG(percpu) -> INT
The kernel can use this information for bpf verification or other
use cases.
Like commit 7472d5a642, this feature requires clang (>= clang14) and
pahole (>= 1.23).
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304191657.981240-3-haoluo@google.com
Pull input updates from Dmitry Torokhov:
- a fixup for Goodix touchscreen driver allowing it to work on certain
Cherry Trail devices
- a fix for imbalanced enable/disable regulator in Elam touchpad driver
that became apparent when used with Asus TF103C 2-in-1 dock
- a couple new input keycodes used on newer keyboards
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
HID: add mapping for KEY_ALL_APPLICATIONS
HID: add mapping for KEY_DICTATE
Input: elan_i2c - fix regulator enable count imbalance after suspend/resume
Input: elan_i2c - move regulator_[en|dis]able() out of elan_[en|dis]able_power()
Input: goodix - workaround Cherry Trail devices with a bogus ACPI Interrupt() resource
Input: goodix - use the new soc_intel_is_byt() helper
Input: samsung-keypad - properly state IOMEM dependency
Add a __diag_ignore_all macro, to ignore warnings for both GCC and LLVM,
without having to specify the compiler type and version. By default, GCC
8 and clang 11 are used. This will be used by bpf subsystem to ignore
-Wmissing-prototypes warning for functions that are meant to be global
functions so that they are in vmlinux BTF, but don't have a prototype.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-7-memxor@gmail.com
Let's ensure that the PTR_TO_BTF_ID reg being passed in to release BPF
helpers and kfuncs always has its offset set to 0. While not a real
problem now, there's a very real possibility this will become a problem
when more and more kfuncs are exposed, and more BPF helpers are added
which can release PTR_TO_BTF_ID.
Previous commits already protected against non-zero var_off. One of the
case we are concerned about now is when we have a type that can be
returned by e.g. an acquire kfunc:
struct foo {
int a;
int b;
struct bar b;
};
... and struct bar is also a type that can be returned by another
acquire kfunc.
Then, doing the following sequence:
struct foo *f = bpf_get_foo(); // acquire kfunc
if (!f)
return 0;
bpf_put_bar(&f->b); // release kfunc
... would work with the current code, since the btf_struct_ids_match
takes reg->off into account for matching pointer type with release kfunc
argument type, but would obviously be incorrect, and most likely lead to
a kernel crash. A test has been included later to prevent regressions in
this area.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-5-memxor@gmail.com
Lift the list of register types allowed for having fixed and variable
offsets when passed as helper function arguments into a common helper,
so that they can be reused for kfunc checks in later commits. Keeping a
common helper aids maintainability and allows us to follow the same
consistent rules across helpers and kfuncs. Also, convert check_func_arg
to use this function.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-2-memxor@gmail.com
A deep process chain with many vmas could grow really high. With
default sysctl_max_map_count (64k) and default pid_max (32k) the max
number of vmas in the system is 2147450880 and the refcounter has
headroom of 1073774592 before it reaches REFCOUNT_SATURATED
(3221225472).
Therefore it's unlikely that an anonymous name refcounter will overflow
with these defaults. Currently the max for pid_max is PID_MAX_LIMIT
(4194304) and for sysctl_max_map_count it's INT_MAX (2147483647). In
this configuration anon_vma_name refcount overflow becomes theoretically
possible (that still require heavy sharing of that anon_vma_name between
processes).
kref refcounting interface used in anon_vma_name structure will detect a
counter overflow when it reaches REFCOUNT_SATURATED value but will only
generate a warning and freeze the ref counter. This would lead to the
refcounted object never being freed. A determined attacker could leak
memory like that but it would be rather expensive and inefficient way to
do so.
To ensure anon_vma_name refcount does not overflow, stop anon_vma_name
sharing when the refcount reaches REFCOUNT_MAX (2147483647), which still
leaves INT_MAX/2 (1073741823) values before the counter reaches
REFCOUNT_SATURATED. This should provide enough headroom for raising the
refcounts temporarily.
Link: https://lkml.kernel.org/r/20220223153613.835563-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Chris Hyser <chris.hyser@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Colin Cross <ccross@google.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
