<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux/kernel/trace/ftrace.c, branch v6.3</title>
<subtitle>Mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
</subtitle>
<id>https://git.shady.money/linux/atom?h=v6.3</id>
<link rel='self' href='https://git.shady.money/linux/atom?h=v6.3'/>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/'/>
<updated>2023-04-06T15:01:30Z</updated>
<entry>
<title>ftrace: Fix issue that 'direct-&gt;addr' not restored in modify_ftrace_direct()</title>
<updated>2023-04-06T15:01:30Z</updated>
<author>
<name>Zheng Yejian</name>
<email>zhengyejian1@huawei.com</email>
</author>
<published>2023-03-30T02:52:23Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=2a2d8c51defb446e8d89a83f42f8e5cd529111e9'/>
<id>urn:sha1:2a2d8c51defb446e8d89a83f42f8e5cd529111e9</id>
<content type='text'>
Syzkaller report a WARNING: "WARN_ON(!direct)" in modify_ftrace_direct().

Root cause is 'direct-&gt;addr' was changed from 'old_addr' to 'new_addr' but
not restored if error happened on calling ftrace_modify_direct_caller().
Then it can no longer find 'direct' by that 'old_addr'.

To fix it, restore 'direct-&gt;addr' to 'old_addr' explicitly in error path.

Link: https://lore.kernel.org/linux-trace-kernel/20230330025223.1046087-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Cc: &lt;mhiramat@kernel.org&gt;
Cc: &lt;mark.rutland@arm.com&gt;
Cc: &lt;ast@kernel.org&gt;
Cc: &lt;daniel@iogearbox.net&gt;
Fixes: 8a141dd7f706 ("ftrace: Fix modify_ftrace_direct.")
Signed-off-by: Zheng Yejian &lt;zhengyejian1@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'trace-v6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace</title>
<updated>2023-03-19T17:46:02Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-19T17:46:02Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=eaba52d63bfcf0047ce3a1bb011b35d4f066df8e'/>
<id>urn:sha1:eaba52d63bfcf0047ce3a1bb011b35d4f066df8e</id>
<content type='text'>
Pull tracing fixes from Steven Rostedt:

 - Fix setting affinity of hwlat threads in containers

   Using sched_set_affinity() has unwanted side effects when being
   called within a container. Use set_cpus_allowed_ptr() instead

 - Fix per cpu thread management of the hwlat tracer:
    - Do not start per_cpu threads if one is already running for the CPU
    - When starting per_cpu threads, do not clear the kthread variable
      as it may already be set to running per cpu threads

 - Fix return value for test_gen_kprobe_cmd()

   On error the return value was overwritten by being set to the result
   of the call from kprobe_event_delete(), which would likely succeed,
   and thus have the function return success

 - Fix splice() reads from the trace file that was broken by commit
   36e2c7421f02 ("fs: don't allow splice read/write without explicit
   ops")

 - Remove obsolete and confusing comment in ring_buffer.c

   The original design of the ring buffer used struct page flags for
   tricks to optimize, which was shortly removed due to them being
   tricks. But a comment for those tricks remained

 - Set local functions and variables to static

* tag 'trace-v6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr
  ring-buffer: remove obsolete comment for free_buffer_page()
  tracing: Make splice_read available again
  ftrace: Set direct_ops storage-class-specifier to static
  trace/hwlat: Do not start per-cpu thread if it is already running
  trace/hwlat: Do not wipe the contents of per-cpu thread data
  tracing/osnoise: set several trace_osnoise.c variables storage-class-specifier to static
  tracing: Fix wrong return in kprobe_event_gen_test.c
</content>
</entry>
<entry>
<title>ftrace: Set direct_ops storage-class-specifier to static</title>
<updated>2023-03-19T16:20:49Z</updated>
<author>
<name>Tom Rix</name>
<email>trix@redhat.com</email>
</author>
<published>2023-03-11T13:51:13Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=8732565549011cabbea08329a1aefd78a68d96c7'/>
<id>urn:sha1:8732565549011cabbea08329a1aefd78a68d96c7</id>
<content type='text'>
smatch reports this warning
kernel/trace/ftrace.c:2594:19: warning:
  symbol 'direct_ops' was not declared. Should it be static?

The variable direct_ops is only used in ftrace.c, so it should be static

Link: https://lore.kernel.org/linux-trace-kernel/20230311135113.711824-1-trix@redhat.com

Signed-off-by: Tom Rix &lt;trix@redhat.com&gt;
Acked-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'trace-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace</title>
<updated>2023-03-15T00:07:54Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-03-15T00:07:54Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=29db00c252c7d0e015f3b436647b6f87d5854833'/>
<id>urn:sha1:29db00c252c7d0e015f3b436647b6f87d5854833</id>
<content type='text'>
Pull tracing fixes from Steven Rostedt:

 - Do not allow histogram values to have modifies. They can cause a NULL
   pointer dereference if they do.

 - Warn if hist_field_name() is passed a NULL. Prevent the NULL pointer
   dereference mentioned above.

 - Fix invalid address look up race in lookup_rec()

 - Define ftrace_stub_graph conditionally to prevent linker errors

 - Always check if RCU is watching at all tracepoint locations

* tag 'trace-v6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Make tracepoint lockdep check actually test something
  ftrace,kcfi: Define ftrace_stub_graph conditionally
  ftrace: Fix invalid address access in lookup_rec() when index is 0
  tracing: Check field value in hist_field_name()
  tracing: Do not let histogram values have some modifiers
</content>
</entry>
<entry>
<title>ftrace: Fix invalid address access in lookup_rec() when index is 0</title>
<updated>2023-03-10T03:17:06Z</updated>
<author>
<name>Chen Zhongjin</name>
<email>chenzhongjin@huawei.com</email>
</author>
<published>2023-03-09T08:02:30Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=ee92fa443358f4fc0017c1d0d325c27b37802504'/>
<id>urn:sha1:ee92fa443358f4fc0017c1d0d325c27b37802504</id>
<content type='text'>
KASAN reported follow problem:

 BUG: KASAN: use-after-free in lookup_rec
 Read of size 8 at addr ffff000199270ff0 by task modprobe
 CPU: 2 Comm: modprobe
 Call trace:
  kasan_report
  __asan_load8
  lookup_rec
  ftrace_location
  arch_check_ftrace_location
  check_kprobe_address_safe
  register_kprobe

When checking pg-&gt;records[pg-&gt;index - 1].ip in lookup_rec(), it can get a
pg which is newly added to ftrace_pages_start in ftrace_process_locs().
Before the first pg-&gt;index++, index is 0 and accessing pg-&gt;records[-1].ip
will cause this problem.

Don't check the ip when pg-&gt;index is 0.

Link: https://lore.kernel.org/linux-trace-kernel/20230309080230.36064-1-chenzhongjin@huawei.com

Cc: stable@vger.kernel.org
Fixes: 9644302e3315 ("ftrace: Speed up search by skipping pages by address")
Suggested-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Chen Zhongjin &lt;chenzhongjin@huawei.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next</title>
<updated>2023-02-22T02:24:12Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-02-22T02:24:12Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=5b7c4cabbb65f5c469464da6c5f614cbd7f730f2'/>
<id>urn:sha1:5b7c4cabbb65f5c469464da6c5f614cbd7f730f2</id>
<content type='text'>
Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb-&gt;head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client &amp; AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant -&gt;clone() test in inet_clone_ulp().
  ...
</content>
</entry>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2023-02-21T23:27:48Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2023-02-21T23:27:48Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=8bf1a529cd664c8e5268381f1e24fe67aa611dd3'/>
<id>urn:sha1:8bf1a529cd664c8e5268381f1e24fe67aa611dd3</id>
<content type='text'>
Pull arm64 updates from Catalin Marinas:

 - Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
   architectural register (ZT0, for the look-up table feature) that
   Linux needs to save/restore

 - Include TPIDR2 in the signal context and add the corresponding
   kselftests

 - Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
   support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
   (ARM CMN) at probe time

 - Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64

 - Permit EFI boot with MMU and caches on. Instead of cleaning the
   entire loaded kernel image to the PoC and disabling the MMU and
   caches before branching to the kernel bare metal entry point, leave
   the MMU and caches enabled and rely on EFI's cacheable 1:1 mapping of
   all of system RAM to populate the initial page tables

 - Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
   kernel (the arm32 kernel only defines the values)

 - Harden the arm64 shadow call stack pointer handling: stash the shadow
   stack pointer in the task struct on interrupt, load it directly from
   this structure

 - Signal handling cleanups to remove redundant validation of size
   information and avoid reading the same data from userspace twice

 - Refactor the hwcap macros to make use of the automatically generated
   ID registers. It should make new hwcaps writing less error prone

 - Further arm64 sysreg conversion and some fixes

 - arm64 kselftest fixes and improvements

 - Pointer authentication cleanups: don't sign leaf functions, unify
   asm-arch manipulation

 - Pseudo-NMI code generation optimisations

 - Minor fixes for SME and TPIDR2 handling

 - Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable,
   replace strtobool() to kstrtobool() in the cpufeature.c code, apply
   dynamic shadow call stack in two passes, intercept pfn changes in
   set_pte_at() without the required break-before-make sequence, attempt
   to dump all instructions on unhandled kernel faults

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (130 commits)
  arm64: fix .idmap.text assertion for large kernels
  kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
  kselftest/arm64: Copy whole EXTRA context
  arm64: kprobes: Drop ID map text from kprobes blacklist
  perf: arm_spe: Print the version of SPE detected
  perf: arm_spe: Add support for SPEv1.2 inverted event filtering
  perf: Add perf_event_attr::config3
  arm64/sme: Fix __finalise_el2 SMEver check
  drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
  arm64/signal: Only read new data when parsing the ZT context
  arm64/signal: Only read new data when parsing the ZA context
  arm64/signal: Only read new data when parsing the SVE context
  arm64/signal: Avoid rereading context frame sizes
  arm64/signal: Make interface for restore_fpsimd_context() consistent
  arm64/signal: Remove redundant size validation from parse_user_sigframe()
  arm64/signal: Don't redundantly verify FPSIMD magic
  arm64/cpufeature: Use helper macros to specify hwcaps
  arm64/cpufeature: Always use symbolic name for feature value in hwcaps
  arm64/sysreg: Initial unsigned annotations for ID registers
  arm64/sysreg: Initial annotation of signed ID registers
  ...
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2023-02-02T22:49:55Z</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2023-02-02T22:49:55Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=82b4a9412b4de2f68679f1403f1d229390ace27e'/>
<id>urn:sha1:82b4a9412b4de2f68679f1403f1d229390ace27e</id>
<content type='text'>
net/core/gro.c
  7d2c89b32587 ("skb: Do mix page pool and page referenced frags in GRO")
  b1a78b9b9886 ("net: add support for ipv4 big tcp")
https://lore.kernel.org/all/20230203094454.5766f160@canb.auug.org.au/

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>ftrace: Export ftrace_free_filter() to modules</title>
<updated>2023-01-24T16:20:58Z</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2023-01-03T12:49:11Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=8be9fbd5345da52f4a74f7f81d55ff9fa0a2958e'/>
<id>urn:sha1:8be9fbd5345da52f4a74f7f81d55ff9fa0a2958e</id>
<content type='text'>
Setting filters on an ftrace ops results in some memory being allocated
for the filter hashes, which must be freed before the ops can be freed.
This can be done by removing every individual element of the hash by
calling ftrace_set_filter_ip() or ftrace_set_filter_ips() with `remove`
set, but this is somewhat error prone as it's easy to forget to remove
an element.

Make it easier to clean this up by exporting ftrace_free_filter(), which
can be used to clean up all of the filter hashes after an ftrace_ops has
been unregistered.

Using this, fix the ftrace-direct* samples to free hashes prior to being
unloaded. All other code either removes individual filters explicitly or
is built-in and already calls ftrace_free_filter().

Link: https://lkml.kernel.org/r/20230103124912.2948963-3-mark.rutland@arm.com

Cc: stable@vger.kernel.org
Cc: Florent Revest &lt;revest@chromium.org&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Fixes: e1067a07cfbc ("ftrace/samples: Add module to test multi direct modify interface")
Fixes: 5fae941b9a6f ("ftrace/samples: Add multi direct interface test module")
Reviewed-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Reviewed-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
</content>
</entry>
<entry>
<title>ftrace: Add DYNAMIC_FTRACE_WITH_CALL_OPS</title>
<updated>2023-01-24T11:49:42Z</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2023-01-23T13:45:56Z</published>
<link rel='alternate' type='text/html' href='https://git.shady.money/linux/commit/?id=cbad0fb2d8d97fa6dd8089c0cc729ced0abacad6'/>
<id>urn:sha1:cbad0fb2d8d97fa6dd8089c0cc729ced0abacad6</id>
<content type='text'>
Architectures without dynamic ftrace trampolines incur an overhead when
multiple ftrace_ops are enabled with distinct filters. in these cases,
each call site calls a common trampoline which uses
ftrace_ops_list_func() to iterate over all enabled ftrace functions, and
so incurs an overhead relative to the size of this list (including RCU
protection overhead).

Architectures with dynamic ftrace trampolines avoid this overhead for
call sites which have a single associated ftrace_ops. In these cases,
the dynamic trampoline is customized to branch directly to the relevant
ftrace function, avoiding the list overhead.

On some architectures it's impractical and/or undesirable to implement
dynamic ftrace trampolines. For example, arm64 has limited branch ranges
and cannot always directly branch from a call site to an arbitrary
address (e.g. from a kernel text address to an arbitrary module
address). Calls from modules to core kernel text can be indirected via
PLTs (allocated at module load time) to address this, but the same is
not possible from calls from core kernel text.

Using an indirect branch from a call site to an arbitrary trampoline is
possible, but requires several more instructions in the function
prologue (or immediately before it), and/or comes with far more complex
requirements for patching.

Instead, this patch adds a new option, where an architecture can
associate each call site with a pointer to an ftrace_ops, placed at a
fixed offset from the call site. A shared trampoline can recover this
pointer and call ftrace_ops::func() without needing to go via
ftrace_ops_list_func(), avoiding the associated overhead.

This avoids issues with branch range limitations, and avoids the need to
allocate and manipulate dynamic trampolines, making it far simpler to
implement and maintain, while having similar performance
characteristics.

Note that this allows for dynamic ftrace_ops to be invoked directly from
an architecture's ftrace_caller trampoline, whereas existing code forces
the use of ftrace_ops_get_list_func(), which is in part necessary to
permit the ftrace_ops to be freed once unregistered *and* to avoid
branch/address-generation range limitation on some architectures (e.g.
where ops-&gt;func is a module address, and may be outside of the direct
branch range for callsites within the main kernel image).

The CALL_OPS approach avoids this problems and is safe as:

* The existing synchronization in ftrace_shutdown() using
  ftrace_shutdown() using synchronize_rcu_tasks_rude() (and
  synchronize_rcu_tasks()) ensures that no tasks hold a stale reference
  to an ftrace_ops (e.g. in the middle of the ftrace_caller trampoline,
  or while invoking ftrace_ops::func), when that ftrace_ops is
  unregistered.

  Arguably this could also be relied upon for the existing scheme,
  permitting dynamic ftrace_ops to be invoked directly when ops-&gt;func is
  in range, but this will require additional logic to handle branch
  range limitations, and is not handled by this patch.

* Each callsite's ftrace_ops pointer literal can hold any valid kernel
  address, and is updated atomically. As an architecture's ftrace_caller
  trampoline will atomically load the ops pointer then dereference
  ops-&gt;func, there is no risk of invoking ops-&gt;func with a mismatches
  ops pointer, and updates to the ops pointer do not require special
  care.

A subsequent patch will implement architectures support for arm64. There
should be no functional change as a result of this patch alone.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Cc: Florent Revest &lt;revest@chromium.org&gt;
Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20230123134603.1064407-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
</entry>
</feed>
