Pull kthread updates from Eric Biederman:
"This updates init and user mode helper tasks to be ordinary user mode
tasks.
Commit 40966e316f ("kthread: Ensure struct kthread is present for
all kthreads") caused init and the user mode helper threads that call
kernel_execve to have struct kthread allocated for them. This struct
kthread going away during execve in turned made a use after free of
struct kthread possible.
Here, commit 343f4c49f2 ("kthread: Don't allocate kthread_struct for
init and umh") is enough to fix the use after free and is simple
enough to be backportable.
The rest of the changes pass struct kernel_clone_args to clean things
up and cause the code to make sense.
In making init and the user mode helpers tasks purely user mode tasks
I ran into two complications. The function task_tick_numa was
detecting tasks without an mm by testing for the presence of
PF_KTHREAD. The initramfs code in populate_initrd_image was using
flush_delayed_fput to ensuere the closing of all it's file descriptors
was complete, and flush_delayed_fput does not work in a userspace
thread.
I have looked and looked and more complications and in my code review
I have not found any, and neither has anyone else with the code
sitting in linux-next"
* tag 'kthread-cleanups-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched: Update task_tick_numa to ignore tasks without an mm
fork: Stop allowing kthreads to call execve
fork: Explicitly set PF_KTHREAD
init: Deal with the init process being a user mode process
fork: Generalize PF_IO_WORKER handling
fork: Explicity test for idle tasks in copy_thread
fork: Pass struct kernel_clone_args into copy_thread
kthread: Don't allocate kthread_struct for init and umh
Pull MM updates from Andrew Morton:
"Almost all of MM here. A few things are still getting finished off,
reviewed, etc.
- Yang Shi has improved the behaviour of khugepaged collapsing of
readonly file-backed transparent hugepages.
- Johannes Weiner has arranged for zswap memory use to be tracked and
managed on a per-cgroup basis.
- Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for
runtime enablement of the recent huge page vmemmap optimization
feature.
- Baolin Wang contributes a series to fix some issues around hugetlb
pagetable invalidation.
- Zhenwei Pi has fixed some interactions between hwpoisoned pages and
virtualization.
- Tong Tiangen has enabled the use of the presently x86-only
page_table_check debugging feature on arm64 and riscv.
- David Vernet has done some fixup work on the memcg selftests.
- Peter Xu has taught userfaultfd to handle write protection faults
against shmem- and hugetlbfs-backed files.
- More DAMON development from SeongJae Park - adding online tuning of
the feature and support for monitoring of fixed virtual address
ranges. Also easier discovery of which monitoring operations are
available.
- Nadav Amit has done some optimization of TLB flushing during
mprotect().
- Neil Brown continues to labor away at improving our swap-over-NFS
support.
- David Hildenbrand has some fixes to anon page COWing versus
get_user_pages().
- Peng Liu fixed some errors in the core hugetlb code.
- Joao Martins has reduced the amount of memory consumed by
device-dax's compound devmaps.
- Some cleanups of the arch-specific pagemap code from Anshuman
Khandual.
- Muchun Song has found and fixed some errors in the TLB flushing of
transparent hugepages.
- Roman Gushchin has done more work on the memcg selftests.
... and, of course, many smaller fixes and cleanups. Notably, the
customary million cleanup serieses from Miaohe Lin"
* tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits)
mm: kfence: use PAGE_ALIGNED helper
selftests: vm: add the "settings" file with timeout variable
selftests: vm: add "test_hmm.sh" to TEST_FILES
selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests
selftests: vm: add migration to the .gitignore
selftests/vm/pkeys: fix typo in comment
ksm: fix typo in comment
selftests: vm: add process_mrelease tests
Revert "mm/vmscan: never demote for memcg reclaim"
mm/kfence: print disabling or re-enabling message
include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace"
include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion"
mm: fix a potential infinite loop in start_isolate_page_range()
MAINTAINERS: add Muchun as co-maintainer for HugeTLB
zram: fix Kconfig dependency warning
mm/shmem: fix shmem folio swapoff hang
cgroup: fix an error handling path in alloc_pagecache_max_30M()
mm: damon: use HPAGE_PMD_SIZE
tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate
nodemask.h: fix compilation error with GCC12
...
Pull x86 splitlock updates from Borislav Petkov:
- Add Raptor Lake to the set of CPU models which support splitlock
- Make life miserable for apps using split locks by slowing them down
considerably while the rest of the system remains responsive. The
hope is it will hurt more and people will really fix their misaligned
locks apps. As a result, free a TIF bit.
* tag 'x86_splitlock_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/split_lock: Enable the split lock feature on Raptor Lake
x86/split-lock: Remove unused TIF_SLD bit
x86/split_lock: Make life miserable for split lockers
Instead of implicitly inheriting PF_KTHREAD from the parent process
examine arguments in kernel_clone_args to see if PF_KTHREAD should be
set. This makes knowledge of which new threads are kernel threads
explicit.
This also makes it so that init and the user mode helper processes
no longer have PF_KTHREAD set.
Link: https://lkml.kernel.org/r/20220506141512.516114-6-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.
The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.
The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size". These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().
Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The architectures ia64 and parisc have special handling for the idle
thread in copy_process. Add a flag named idle to kernel_clone_args
and use it to explicity test if an idle process is being created.
Fullfill the expectations of the rest of the copy_thread
implemetations and pass a function pointer in .stack from fork_idle().
This makes what is happening in copy_thread better defined, and is
useful to make idle threads less special.
Link: https://lkml.kernel.org/r/20220506141512.516114-3-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.
The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.
Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.
v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.
This bug was introduced by commit 40966e316f ("kthread: Ensure
struct kthread is present for all kthreads"). When kthread_struct
started to be allocated for all tasks that have PF_KTHREAD set. This
in turn required the kthread_struct to be freed in kernel_execve and
violated the assumption that kthread_struct will have the same
lifetime as the task.
Looking a bit deeper this only applies to callers of kernel_execve
which is just the init process and the user mode helper processes.
These processes really don't want to be kernel threads but are for
historical reasons. Mostly that copy_thread does not know how to take
a kernel mode function to the process with for processes without
PF_KTHREAD or PF_IO_WORKER set.
Solve this by not allocating kthread_struct for the init process and
the user mode helper processes.
This is done by adding a kthread member to struct kernel_clone_args.
Setting kthread in fork_idle and kernel_thread. Adding
user_mode_thread that works like kernel_thread except it does not set
kthread. In fork only allocating the kthread_struct if .kthread is set.
I have looked at kernel/kthread.c and since commit 40966e316f
("kthread: Ensure struct kthread is present for all kthreads") there
have been no assumptions added that to_kthread or __to_kthread will
not return NULL.
There are a few callers of to_kthread or __to_kthread that assume a
non-NULL struct kthread pointer will be returned. These functions are
kthread_data(), kthread_parmme(), kthread_exit(), kthread(),
kthread_park(), kthread_unpark(), kthread_stop(). All of those functions
can reasonably expected to be called when it is know that a task is a
kthread so that assumption seems reasonable.
Cc: stable@vger.kernel.org
Fixes: 40966e316f ("kthread: Ensure struct kthread is present for all kthreads")
Reported-by: Максим Кутявин <maximkabox13@gmail.com>
Link: https://lkml.kernel.org/r/20220506141512.516114-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The PASID is being freed too early. It needs to stay around until after
device drivers that might be using it have had a chance to clear it out
of the hardware.
The relevant refcounts are:
mmget() /mmput() refcount the mm's address space
mmgrab()/mmdrop() refcount the mm itself
The PASID is currently tied to the life of the mm's address space and freed
in __mmput(). This makes logical sense because the PASID can't be used
once the address space is gone.
But, this misses an important point: even after the address space is gone,
the PASID will still be programmed into a device. Device drivers might,
for instance, still need to flush operations that are outstanding and need
to use that PASID. They do this at file->release() time.
Device drivers call the IOMMU driver to hold a reference on the mm itself
and drop it at file->release() time. But, the IOMMU driver holds a
reference on the mm itself, not the address space. The address space (and
the PASID) is long gone by the time the driver tries to clean up. This is
effectively a use-after-free bug on the PASID.
To fix this, move the PASID free operation from __mmput() to __mmdrop().
This ensures that the IOMMU driver's existing mmgrab() keeps the PASID
allocated until it drops its mm reference.
Fixes: 701fac4038 ("iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit")
Reported-by: Zhangfei Gao <zhangfei.gao@foxmail.com>
Suggested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Zhangfei Gao <zhangfei.gao@foxmail.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20220428180041.806809-1-fenghua.yu@intel.com
In https://lore.kernel.org/all/87y22uujkm.ffs@tglx/ Thomas
said:
Its's simply wishful thinking that stuff gets fixed because of a
WARN_ONCE(). This has never worked. The only thing which works is to
make stuff fail hard or slow it down in a way which makes it annoying
enough to users to complain.
He was talking about WBINVD. But it made me think about how we use the
split lock detection feature in Linux.
Existing code has three options for applications:
1) Don't enable split lock detection (allow arbitrary split locks)
2) Warn once when a process uses split lock, but let the process
keep running with split lock detection disabled
3) Kill process that use split locks
Option 2 falls into the "wishful thinking" territory that Thomas warns does
nothing. But option 3 might not be viable in a situation with legacy
applications that need to run.
Hence make option 2 much stricter to "slow it down in a way which makes
it annoying".
Primary reason for this change is to provide better quality of service to
the rest of the applications running on the system. Internal testing shows
that even with many processes splitting locks, performance for the rest of
the system is much more responsive.
The new "warn" mode operates like this. When an application tries to
execute a bus lock the #AC handler.
1) Delays (interruptibly) 10 ms before moving to next step.
2) Blocks (interruptibly) until it can get the semaphore
If interrupted, just return. Assume the signal will either
kill the task, or direct execution away from the instruction
that is trying to get the bus lock.
3) Disables split lock detection for the current core
4) Schedules a work queue to re-enable split lock detect in 2 jiffies
5) Returns
The work queue that re-enables split lock detection also releases the
semaphore.
There is a corner case where a CPU may be taken offline while split lock
detection is disabled. A CPU hotplug handler handles this case.
Old behaviour was to only print the split lock warning on the first
occurrence of a split lock from a task. Preserve that by adding a flag to
the task structure that suppresses subsequent split lock messages from that
task.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220310204854.31752-2-tony.luck@intel.com
Pull networking updates from Jakub Kicinski:
"The sprinkling of SPI drivers is because we added a new one and Mark
sent us a SPI driver interface conversion pull request.
Core
----
- Introduce XDP multi-buffer support, allowing the use of XDP with
jumbo frame MTUs and combination with Rx coalescing offloads (LRO).
- Speed up netns dismantling (5x) and lower the memory cost a little.
Remove unnecessary per-netns sockets. Scope some lists to a netns.
Cut down RCU syncing. Use batch methods. Allow netdev registration
to complete out of order.
- Support distinguishing timestamp types (ingress vs egress) and
maintaining them across packet scrubbing points (e.g. redirect).
- Continue the work of annotating packet drop reasons throughout the
stack.
- Switch netdev error counters from an atomic to dynamically
allocated per-CPU counters.
- Rework a few preempt_disable(), local_irq_save() and busy waiting
sections problematic on PREEMPT_RT.
- Extend the ref_tracker to allow catching use-after-free bugs.
BPF
---
- Introduce "packing allocator" for BPF JIT images. JITed code is
marked read only, and used to be allocated at page granularity.
Custom allocator allows for more efficient memory use, lower iTLB
pressure and prevents identity mapping huge pages from getting
split.
- Make use of BTF type annotations (e.g. __user, __percpu) to enforce
the correct probe read access method, add appropriate helpers.
- Convert the BPF preload to use light skeleton and drop the
user-mode-driver dependency.
- Allow XDP BPF_PROG_RUN test infra to send real packets, enabling
its use as a packet generator.
- Allow local storage memory to be allocated with GFP_KERNEL if
called from a hook allowed to sleep.
- Introduce fprobe (multi kprobe) to speed up mass attachment (arch
bits to come later).
- Add unstable conntrack lookup helpers for BPF by using the BPF
kfunc infra.
- Allow cgroup BPF progs to return custom errors to user space.
- Add support for AF_UNIX iterator batching.
- Allow iterator programs to use sleepable helpers.
- Support JIT of add, and, or, xor and xchg atomic ops on arm64.
- Add BTFGen support to bpftool which allows to use CO-RE in kernels
without BTF info.
- Large number of libbpf API improvements, cleanups and deprecations.
Protocols
---------
- Micro-optimize UDPv6 Tx, gaining up to 5% in test on dummy netdev.
- Adjust TSO packet sizes based on min_rtt, allowing very low latency
links (data centers) to always send full-sized TSO super-frames.
- Make IPv6 flow label changes (AKA hash rethink) more configurable,
via sysctl and setsockopt. Distinguish between server and client
behavior.
- VxLAN support to "collect metadata" devices to terminate only
configured VNIs. This is similar to VLAN filtering in the bridge.
- Support inserting IPv6 IOAM information to a fraction of frames.
- Add protocol attribute to IP addresses to allow identifying where
given address comes from (kernel-generated, DHCP etc.)
- Support setting socket and IPv6 options via cmsg on ping6 sockets.
- Reject mis-use of ECN bits in IP headers as part of DSCP/TOS.
Define dscp_t and stop taking ECN bits into account in fib-rules.
- Add support for locked bridge ports (for 802.1X).
- tun: support NAPI for packets received from batched XDP buffs,
doubling the performance in some scenarios.
- IPv6 extension header handling in Open vSwitch.
- Support IPv6 control message load balancing in bonding, prevent
neighbor solicitation and advertisement from using the wrong port.
Support NS/NA monitor selection similar to existing ARP monitor.
- SMC
- improve performance with TCP_CORK and sendfile()
- support auto-corking
- support TCP_NODELAY
- MCTP (Management Component Transport Protocol)
- add user space tag control interface
- I2C binding driver (as specified by DMTF DSP0237)
- Multi-BSSID beacon handling in AP mode for WiFi.
- Bluetooth:
- handle MSFT Monitor Device Event
- add MGMT Adv Monitor Device Found/Lost events
- Multi-Path TCP:
- add support for the SO_SNDTIMEO socket option
- lots of selftest cleanups and improvements
- Increase the max PDU size in CAN ISOTP to 64 kB.
Driver API
----------
- Add HW counters for SW netdevs, a mechanism for devices which
offload packet forwarding to report packet statistics back to
software interfaces such as tunnels.
- Select the default NIC queue count as a fraction of number of
physical CPU cores, instead of hard-coding to 8.
- Expose devlink instance locks to drivers. Allow device layer of
drivers to use that lock directly instead of creating their own
which always runs into ordering issues in devlink callbacks.
- Add header/data split indication to guide user space enabling of
TCP zero-copy Rx.
- Allow configuring completion queue event size.
- Refactor page_pool to enable fragmenting after allocation.
- Add allocation and page reuse statistics to page_pool.
- Improve Multiple Spanning Trees support in the bridge to allow
reuse of topologies across VLANs, saving HW resources in switches.
- DSA (Distributed Switch Architecture):
- replay and offload of host VLAN entries
- offload of static and local FDB entries on LAG interfaces
- FDB isolation and unicast filtering
New hardware / drivers
----------------------
- Ethernet:
- LAN937x T1 PHYs
- Davicom DM9051 SPI NIC driver
- Realtek RTL8367S, RTL8367RB-VB switch and MDIO
- Microchip ksz8563 switches
- Netronome NFP3800 SmartNICs
- Fungible SmartNICs
- MediaTek MT8195 switches
- WiFi:
- mt76: MediaTek mt7916
- mt76: MediaTek mt7921u USB adapters
- brcmfmac: Broadcom BCM43454/6
- Mobile:
- iosm: Intel M.2 7360 WWAN card
Drivers
-------
- Convert many drivers to the new phylink API built for split PCS
designs but also simplifying other cases.
- Intel Ethernet NICs:
- add TTY for GNSS module for E810T device
- improve AF_XDP performance
- GTP-C and GTP-U filter offload
- QinQ VLAN support
- Mellanox Ethernet NICs (mlx5):
- support xdp->data_meta
- multi-buffer XDP
- offload tc push_eth and pop_eth actions
- Netronome Ethernet NICs (nfp):
- flow-independent tc action hardware offload (police / meter)
- AF_XDP
- Other Ethernet NICs:
- at803x: fiber and SFP support
- xgmac: mdio: preamble suppression and custom MDC frequencies
- r8169: enable ASPM L1.2 if system vendor flags it as safe
- macb/gem: ZynqMP SGMII
- hns3: add TX push mode
- dpaa2-eth: software TSO
- lan743x: multi-queue, mdio, SGMII, PTP
- axienet: NAPI and GRO support
- Mellanox Ethernet switches (mlxsw):
- source and dest IP address rewrites
- RJ45 ports
- Marvell Ethernet switches (prestera):
- basic routing offload
- multi-chain TC ACL offload
- NXP embedded Ethernet switches (ocelot & felix):
- PTP over UDP with the ocelot-8021q DSA tagging protocol
- basic QoS classification on Felix DSA switch using dcbnl
- port mirroring for ocelot switches
- Microchip high-speed industrial Ethernet (sparx5):
- offloading of bridge port flooding flags
- PTP Hardware Clock
- Other embedded switches:
- lan966x: PTP Hardward Clock
- qca8k: mdio read/write operations via crafted Ethernet packets
- Qualcomm 802.11ax WiFi (ath11k):
- add LDPC FEC type and 802.11ax High Efficiency data in radiotap
- enable RX PPDU stats in monitor co-exist mode
- Intel WiFi (iwlwifi):
- UHB TAS enablement via BIOS
- band disablement via BIOS
- channel switch offload
- 32 Rx AMPDU sessions in newer devices
- MediaTek WiFi (mt76):
- background radar detection
- thermal management improvements on mt7915
- SAR support for more mt76 platforms
- MBSSID and 6 GHz band on mt7915
- RealTek WiFi:
- rtw89: AP mode
- rtw89: 160 MHz channels and 6 GHz band
- rtw89: hardware scan
- Bluetooth:
- mt7921s: wake on Bluetooth, SCO over I2S, wide-band-speed (WBS)
- Microchip CAN (mcp251xfd):
- multiple RX-FIFOs and runtime configurable RX/TX rings
- internal PLL, runtime PM handling simplification
- improve chip detection and error handling after wakeup"
* tag 'net-next-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2521 commits)
llc: fix netdevice reference leaks in llc_ui_bind()
drivers: ethernet: cpsw: fix panic when interrupt coaleceing is set via ethtool
ice: don't allow to run ice_send_event_to_aux() in atomic ctx
ice: fix 'scheduling while atomic' on aux critical err interrupt
net/sched: fix incorrect vlan_push_eth dest field
net: bridge: mst: Restrict info size queries to bridge ports
net: marvell: prestera: add missing destroy_workqueue() in prestera_module_init()
drivers: net: xgene: Fix regression in CRC stripping
net: geneve: add missing netlink policy and size for IFLA_GENEVE_INNER_PROTO_INHERIT
net: dsa: fix missing host-filtered multicast addresses
net/mlx5e: Fix build warning, detected write beyond size of field
iwlwifi: mvm: Don't fail if PPAG isn't supported
selftests/bpf: Fix kprobe_multi test.
Revert "rethook: x86: Add rethook x86 implementation"
Revert "arm64: rethook: Add arm64 rethook implementation"
Revert "powerpc: Add rethook support"
Revert "ARM: rethook: Add rethook arm implementation"
netdevice: add missing dm_private kdoc
net: bridge: mst: prevent NULL deref in br_mst_info_size()
selftests: forwarding: Use same VRF for port and VLAN upper
...
Alexei Starovoitov says:
====================
pull-request: bpf-next 2022-03-21 v2
We've added 137 non-merge commits during the last 17 day(s) which contain
a total of 143 files changed, 7123 insertions(+), 1092 deletions(-).
The main changes are:
1) Custom SEC() handling in libbpf, from Andrii.
2) subskeleton support, from Delyan.
3) Use btf_tag to recognize __percpu pointers in the verifier, from Hao.
4) Fix net.core.bpf_jit_harden race, from Hou.
5) Fix bpf_sk_lookup remote_port on big-endian, from Jakub.
6) Introduce fprobe (multi kprobe) _without_ arch bits, from Masami.
The arch specific bits will come later.
7) Introduce multi_kprobe bpf programs on top of fprobe, from Jiri.
8) Enable non-atomic allocations in local storage, from Joanne.
9) Various var_off ptr_to_btf_id fixed, from Kumar.
10) bpf_ima_file_hash helper, from Roberto.
11) Add "live packet" mode for XDP in BPF_PROG_RUN, from Toke.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (137 commits)
selftests/bpf: Fix kprobe_multi test.
Revert "rethook: x86: Add rethook x86 implementation"
Revert "arm64: rethook: Add arm64 rethook implementation"
Revert "powerpc: Add rethook support"
Revert "ARM: rethook: Add rethook arm implementation"
bpftool: Fix a bug in subskeleton code generation
bpf: Fix bpf_prog_pack when PMU_SIZE is not defined
bpf: Fix bpf_prog_pack for multi-node setup
bpf: Fix warning for cast from restricted gfp_t in verifier
bpf, arm: Fix various typos in comments
libbpf: Close fd in bpf_object__reuse_map
bpftool: Fix print error when show bpf map
bpf: Fix kprobe_multi return probe backtrace
Revert "bpf: Add support to inline bpf_get_func_ip helper on x86"
bpf: Simplify check in btf_parse_hdr()
selftests/bpf/test_lirc_mode2.sh: Exit with proper code
bpf: Check for NULL return from bpf_get_btf_vmlinux
selftests/bpf: Test skipping stacktrace
bpf: Adjust BPF stack helper functions to accommodate skip > 0
bpf: Select proper size for bpf_prog_pack
...
====================
Link: https://lore.kernel.org/r/20220322050159.5507-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull core process handling RT latency updates from Thomas Gleixner:
- Reduce the amount of work to release a task stack in context switch.
There is no real reason to do cgroup accounting and memory freeing in
this performance sensitive context.
Aside of this the invoked functions cannot be called from this
preemption disabled context on PREEMPT_RT enabled kernels. Solve this
by moving the accounting into do_exit() and delaying the freeing of
the stack unless the vmap stack can be cached.
- Provide a mechanism to delay raising signals from atomic context on
PREEMPT_RT enabled kernels as sighand::lock cannot be acquired. Store
the information in the task struct and raise it in the exit path.
* tag 'core-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
signal, x86: Delay calling signals in atomic on RT enabled kernels
fork: Use IS_ENABLED() in account_kernel_stack()
fork: Only cache the VMAP stack in finish_task_switch()
fork: Move task stack accounting to do_exit()
fork: Move memcg_charge_kernel_stack() into CONFIG_VMAP_STACK
fork: Don't assign the stack pointer in dup_task_struct()
fork, IA64: Provide alloc_thread_stack_node() for IA64
fork: Duplicate task_struct before stack allocation
fork: Redo ifdefs around task stack handling
Pull x86 PASID support from Thomas Gleixner:
"Reenable ENQCMD/PASID support:
- Simplify the PASID handling to allocate the PASID once, associate
it to the mm of a process and free it on mm_exit().
The previous attempt of refcounted PASIDs and dynamic
alloc()/free() turned out to be error prone and too complex. The
PASID space is 20bits, so the case of resource exhaustion is a pure
academic concern.
- Populate the PASID MSR on demand via #GP to avoid racy updates via
IPIs.
- Reenable ENQCMD and let objtool check for the forbidden usage of
ENQCMD in the kernel.
- Update the documentation for Shared Virtual Addressing accordingly"
* tag 'x86-pasid-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation/x86: Update documentation for SVA (Shared Virtual Addressing)
tools/objtool: Check for use of the ENQCMD instruction in the kernel
x86/cpufeatures: Re-enable ENQCMD
x86/traps: Demand-populate PASID MSR via #GP
sched: Define and initialize a flag to identify valid PASID in the task
x86/fpu: Clear PASID when copying fpstate
iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
kernel/fork: Initialize mm's PASID
iommu/ioasid: Introduce a helper to check for valid PASIDs
mm: Change CONFIG option for mm->pasid field
iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA
Add a return hook framework which hooks the function return. Most of the
logic came from the kretprobe, but this is independent from kretprobe.
Note that this is expected to be used with other function entry hooking
feature, like ftrace, fprobe, adn kprobes. Eventually this will replace
the kretprobe (e.g. kprobe + rethook = kretprobe), but at this moment,
this is just an additional hook.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735285066.1084943.9259661137330166643.stgit@devnote2
The task stack could be deallocated later, but for fork()/exec() kind of
workloads (say a shell script executing several commands) it is important
that the stack is released in finish_task_switch() so that in VMAP_STACK
case it can be cached and reused in the new task.
For PREEMPT_RT it would be good if the wake-up in vfree_atomic() could
be avoided in the scheduling path. Far worse are the other
free_thread_stack() implementations which invoke __free_pages()/
kmem_cache_free() with disabled preemption.
Cache the stack in free_thread_stack() in the VMAP_STACK case and
RCU-delay the free path otherwise. Free the stack in the RCU callback.
In the VMAP_STACK case this is another opportunity to fill the cache.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-8-bigeasy@linutronix.de
There is no need to perform the stack accounting of the outgoing task in
its final schedule() invocation which happens with preemption disabled.
The task is leaving, the resources will be freed and the accounting can
happen in do_exit() before the actual schedule invocation which
frees the stack memory.
Move the accounting of the stack memory from release_task_stack() to
exit_task_stack_account() which then can be invoked from do_exit().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-7-bigeasy@linutronix.de
Provide a generic alloc_thread_stack_node() for IA64 and
CONFIG_ARCH_THREAD_STACK_ALLOCATOR which returns stack pointer and sets
task_struct::stack so it behaves exactly like the other implementations.
Rename IA64's alloc_thread_stack_node() and add the generic version to the
fork code so it is in one place _and_ to drastically lower the chances of
fat fingering the IA64 code. Do the same for free_thread_stack().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-4-bigeasy@linutronix.de
