user/sven/linux.git/include/linux/rcupdate.h, branch v6.4.9

mm/slab: document kfree() as allowed for kmem_cache_alloc() objects

2023-03-29T08:35:41Z

This will make it easier to free objects in situations when they can come from either kmalloc() or kmem_cache_alloc(), and also allow kfree_rcu() for freeing objects from kmem_cache_alloc(). For the SLAB and SLUB allocators this was always possible so with SLOB gone, we can document it as supported. Signed-off-by: Vlastimil Babka Reviewed-by: Mike Rapoport (IBM) Cc: Jonathan Corbet Cc: "Paul E. McKenney" Cc: Frederic Weisbecker Cc: Neeraj Upadhyay Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes

Merge branches 'doc.2023.01.05a', 'fixes.2023.01.23a', 'kvfree.2023.01.03a', 'srcu.2023.01.03a', 'srcu-always.2023.02.02a', 'tasks.2023.01.03a', 'torture.2023.01.05a' and 'torturescript.2023.01.03a' into HEAD

2023-02-03T00:33:43Z

doc.2023.01.05a: Documentation update. fixes.2023.01.23a: Miscellaneous fixes. kvfree.2023.01.03a: kvfree_rcu() updates. srcu.2023.01.03a: SRCU updates. srcu-always.2023.02.02a: Finish making SRCU be unconditionally available. tasks.2023.01.03a: Tasks-RCU updates. torture.2023.01.05a: Torture-test updates. torturescript.2023.01.03a: Torture-test scripting updates.

rcu/kvfree: Add kvfree_rcu_mightsleep() and kfree_rcu_mightsleep()

2023-02-03T00:28:07Z

The kvfree_rcu() and kfree_rcu() APIs are hazardous in that if you forget the second argument, it works, but might sleep. This sleeping can be a correctness bug from atomic contexts, and even in non-atomic contexts it might introduce unacceptable latencies. This commit therefore adds kvfree_rcu_mightsleep() and kfree_rcu_mightsleep(), which will replace the single-argument kvfree_rcu() and kfree_rcu(), respectively. This commit enables a series of commits that switch from single-argument kvfree_rcu() and kfree_rcu() to their _mightsleep() counterparts. Once all of these commits land, the single-argument versions will be removed. Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Paul E. McKenney

rcu-tasks: Fix synchronize_rcu_tasks() VS zap_pid_ns_processes()

2023-01-04T01:52:16Z

RCU Tasks and PID-namespace unshare can interact in do_exit() in a complicated circular dependency: 1) TASK A calls unshare(CLONE_NEWPID), this creates a new PID namespace that every subsequent child of TASK A will belong to. But TASK A doesn't itself belong to that new PID namespace. 2) TASK A forks() and creates TASK B. TASK A stays attached to its PID namespace (let's say PID_NS1) and TASK B is the first task belonging to the new PID namespace created by unshare() (let's call it PID_NS2). 3) Since TASK B is the first task attached to PID_NS2, it becomes the PID_NS2 child reaper. 4) TASK A forks() again and creates TASK C which get attached to PID_NS2. Note how TASK C has TASK A as a parent (belonging to PID_NS1) but has TASK B (belonging to PID_NS2) as a pid_namespace child_reaper. 5) TASK B exits and since it is the child reaper for PID_NS2, it has to kill all other tasks attached to PID_NS2, and wait for all of them to die before getting reaped itself (zap_pid_ns_process()). 6) TASK A calls synchronize_rcu_tasks() which leads to synchronize_srcu(&tasks_rcu_exit_srcu). 7) TASK B is waiting for TASK C to get reaped. But TASK B is under a tasks_rcu_exit_srcu SRCU critical section (exit_notify() is between exit_tasks_rcu_start() and exit_tasks_rcu_finish()), blocking TASK A. 8) TASK C exits and since TASK A is its parent, it waits for it to reap TASK C, but it can't because TASK A waits for TASK B that waits for TASK C. Pid_namespace semantics can hardly be changed at this point. But the coverage of tasks_rcu_exit_srcu can be reduced instead. The current task is assumed not to be concurrently reapable at this stage of exit_notify() and therefore tasks_rcu_exit_srcu can be temporarily relaxed without breaking its constraints, providing a way out of the deadlock scenario. [ paulmck: Fix build failure by adding additional declaration. ] Fixes: 3f95aa81d265 ("rcu: Make TASKS_RCU handle tasks that are almost done exiting") Reported-by: Pengfei Xu Suggested-by: Boqun Feng Suggested-by: Neeraj Upadhyay Suggested-by: Paul E. McKenney Cc: Oleg Nesterov Cc: Lai Jiangshan Cc: Eric W . Biederman Signed-off-by: Frederic Weisbecker Signed-off-by: Paul E. McKenney

rcu: Refactor kvfree_call_rcu() and high-level helpers

2023-01-04T01:48:40Z

Currently a kvfree_call_rcu() takes an offset within a structure as a second parameter, so a helper such as a kvfree_rcu_arg_2() has to convert rcu_head and a freed ptr to an offset in order to pass it. That leads to an extra conversion on macro entry. Instead of converting, refactor the code in way that a pointer that has to be freed is passed directly to the kvfree_call_rcu(). This patch does not make any functional change and is transparent to all kvfree_rcu() users. Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Paul E. McKenney

rcu: Make RCU_LOCKDEP_WARN() avoid early lockdep checks

2023-01-04T01:28:34Z

Currently, RCU_LOCKDEP_WARN() checks the condition before checking to see if lockdep is still enabled. This is necessary to avoid the false-positive splats fixed by commit 3066820034b5dd ("rcu: Reject RCU_LOCKDEP_WARN() false positives"). However, the current state can result in false-positive splats during early boot before lockdep is fully initialized. This commit therefore checks debug_lockdep_rcu_enabled() both before and after checking the condition, thus avoiding both sets of false-positive error reports. Reported-by: Steven Rostedt Reported-by: Masami Hiramatsu (Google) Reported-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney Reviewed-by: Mathieu Desnoyers Cc: Boqun Feng Cc: Matthew Wilcox Cc: Thomas Gleixner

Merge tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

2022-12-13T23:47:48Z

Pull networking updates from Paolo Abeni: "Core: - Allow live renaming when an interface is up - Add retpoline wrappers for tc, improving considerably the performances of complex queue discipline configurations - Add inet drop monitor support - A few GRO performance improvements - Add infrastructure for atomic dev stats, addressing long standing data races - De-duplicate common code between OVS and conntrack offloading infrastructure - A bunch of UBSAN_BOUNDS/FORTIFY_SOURCE improvements - Netfilter: introduce packet parser for tunneled packets - Replace IPVS timer-based estimators with kthreads to scale up the workload with the number of available CPUs - Add the helper support for connection-tracking OVS offload BPF: - Support for user defined BPF objects: the use case is to allocate own objects, build own object hierarchies and use the building blocks to build own data structures flexibly, for example, linked lists in BPF - Make cgroup local storage available to non-cgroup attached BPF programs - Avoid unnecessary deadlock detection and failures wrt BPF task storage helpers - A relevant bunch of BPF verifier fixes and improvements - Veristat tool improvements to support custom filtering, sorting, and replay of results - Add LLVM disassembler as default library for dumping JITed code - Lots of new BPF documentation for various BPF maps - Add bpf_rcu_read_{,un}lock() support for sleepable programs - Add RCU grace period chaining to BPF to wait for the completion of access from both sleepable and non-sleepable BPF programs - Add support storing struct task_struct objects as kptrs in maps - Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer values - Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions Protocols: - TCP: implement Protective Load Balancing across switch links - TCP: allow dynamically disabling TCP-MD5 static key, reverting back to fast[er]-path - UDP: Introduce optional per-netns hash lookup table - IPv6: simplify and cleanup sockets disposal - Netlink: support different type policies for each generic netlink operation - MPTCP: add MSG_FASTOPEN and FastOpen listener side support - MPTCP: add netlink notification support for listener sockets events - SCTP: add VRF support, allowing sctp sockets binding to VRF devices - Add bridging MAC Authentication Bypass (MAB) support - Extensions for Ethernet VPN bridging implementation to better support multicast scenarios - More work for Wi-Fi 7 support, comprising conversion of all the existing drivers to internal TX queue usage - IPSec: introduce a new offload type (packet offload) allowing complete header processing and crypto offloading - IPSec: extended ack support for more descriptive XFRM error reporting - RXRPC: increase SACK table size and move processing into a per-local endpoint kernel thread, reducing considerably the required locking - IEEE 802154: synchronous send frame and extended filtering support, initial support for scanning available 15.4 networks - Tun: bump the link speed from 10Mbps to 10Gbps - Tun/VirtioNet: implement UDP segmentation offload support Driver API: - PHY/SFP: improve power level switching between standard level 1 and the higher power levels - New API for netdev <-> devlink_port linkage - PTP: convert existing drivers to new frequency adjustment implementation - DSA: add support for rx offloading - Autoload DSA tagging driver when dynamically changing protocol - Add new PCP and APPTRUST attributes to Data Center Bridging - Add configuration support for 800Gbps link speed - Add devlink port function attribute to enable/disable RoCE and migratable - Extend devlink-rate to support strict prioriry and weighted fair queuing - Add devlink support to directly reading from region memory - New device tree helper to fetch MAC address from nvmem - New big TCP helper to simplify temporary header stripping New hardware / drivers: - Ethernet: - Marvel Octeon CNF95N and CN10KB Ethernet Switches - Marvel Prestera AC5X Ethernet Switch - WangXun 10 Gigabit NIC - Motorcomm yt8521 Gigabit Ethernet - Microchip ksz9563 Gigabit Ethernet Switch - Microsoft Azure Network Adapter - Linux Automation 10Base-T1L adapter - PHY: - Aquantia AQR112 and AQR412 - Motorcomm YT8531S - PTP: - Orolia ART-CARD - WiFi: - MediaTek Wi-Fi 7 (802.11be) devices - RealTek rtw8821cu, rtw8822bu, rtw8822cu and rtw8723du USB devices - Bluetooth: - Broadcom BCM4377/4378/4387 Bluetooth chipsets - Realtek RTL8852BE and RTL8723DS - Cypress.CYW4373A0 WiFi + Bluetooth combo device Drivers: - CAN: - gs_usb: bus error reporting support - kvaser_usb: listen only and bus error reporting support - Ethernet NICs: - Intel (100G): - extend action skbedit to RX queue mapping - implement devlink-rate support - support direct read from memory - nVidia/Mellanox (mlx5): - SW steering improvements, increasing rules update rate - Support for enhanced events compression - extend H/W offload packet manipulation capabilities - implement IPSec packet offload mode - nVidia/Mellanox (mlx4): - better big TCP support - Netronome Ethernet NICs (nfp): - IPsec offload support - add support for multicast filter - Broadcom: - RSS and PTP support improvements - AMD/SolarFlare: - netlink extened ack improvements - add basic flower matches to offload, and related stats - Virtual NICs: - ibmvnic: introduce affinity hint support - small / embedded: - FreeScale fec: add initial XDP support - Marvel mv643xx_eth: support MII/GMII/RGMII modes for Kirkwood - TI am65-cpsw: add suspend/resume support - Mediatek MT7986: add RX wireless wthernet dispatch support - Realtek 8169: enable GRO software interrupt coalescing per default - Ethernet high-speed switches: - Microchip (sparx5): - add support for Sparx5 TC/flower H/W offload via VCAP - Mellanox mlxsw: - add 802.1X and MAC Authentication Bypass offload support - add ip6gre support - Embedded Ethernet switches: - Mediatek (mtk_eth_soc): - improve PCS implementation, add DSA untag support - enable flow offload support - Renesas: - add rswitch R-Car Gen4 gPTP support - Microchip (lan966x): - add full XDP support - add TC H/W offload via VCAP - enable PTP on bridge interfaces - Microchip (ksz8): - add MTU support for KSZ8 series - Qualcomm 802.11ax WiFi (ath11k): - support configuring channel dwell time during scan - MediaTek WiFi (mt76): - enable Wireless Ethernet Dispatch (WED) offload support - add ack signal support - enable coredump support - remain_on_channel support - Intel WiFi (iwlwifi): - enable Wi-Fi 7 Extremely High Throughput (EHT) PHY capabilities - 320 MHz channels support - RealTek WiFi (rtw89): - new dynamic header firmware format support - wake-over-WLAN support" * tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2002 commits) ipvs: fix type warning in do_div() on 32 bit net: lan966x: Remove a useless test in lan966x_ptp_add_trap() net: ipa: add IPA v4.7 support dt-bindings: net: qcom,ipa: Add SM6350 compatible bnxt: Use generic HBH removal helper in tx path IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver selftests: forwarding: Add bridge MDB test selftests: forwarding: Rename bridge_mdb test bridge: mcast: Support replacement of MDB port group entries bridge: mcast: Allow user space to specify MDB entry routing protocol bridge: mcast: Allow user space to add (*, G) with a source list and filter mode bridge: mcast: Add support for (*, G) with a source list and filter mode bridge: mcast: Avoid arming group timer when (S, G) corresponds to a source bridge: mcast: Add a flag for user installed source entries bridge: mcast: Expose __br_multicast_del_group_src() bridge: mcast: Expose br_multicast_new_group_src() bridge: mcast: Add a centralized error path bridge: mcast: Place netlink policy before validation functions bridge: mcast: Split (*, G) and (S, G) addition into different functions bridge: mcast: Do not derive entry type from its filter mode ...

Merge branches 'doc.2022.10.20a', 'fixes.2022.10.21a', 'lazy.2022.11.30a', 'srcunmisafe.2022.11.09a', 'torture.2022.10.18c' and 'torturescript.2022.10.20a' into HEAD

2022-11-30T21:20:05Z

doc.2022.10.20a: Documentation updates. fixes.2022.10.21a: Miscellaneous fixes. lazy.2022.11.30a: Lazy call_rcu() and NOCB updates. srcunmisafe.2022.11.09a: NMI-safe SRCU readers. torture.2022.10.18c: Torture-test updates. torturescript.2022.10.20a: Torture-test scripting updates.

rcu: Make call_rcu() lazy to save power

2022-11-29T22:02:23Z

Implement timer-based RCU callback batching (also known as lazy callbacks). With this we save about 5-10% of power consumed due to RCU requests that happen when system is lightly loaded or idle. By default, all async callbacks (queued via call_rcu) are marked lazy. An alternate API call_rcu_hurry() is provided for the few users, for example synchronize_rcu(), that need the old behavior. The batch is flushed whenever a certain amount of time has passed, or the batch on a particular CPU grows too big. Also memory pressure will flush it in a future patch. To handle several corner cases automagically (such as rcu_barrier() and hotplug), we re-use bypass lists which were originally introduced to address lock contention, to handle lazy CBs as well. The bypass list length has the lazy CB length included in it. A separate lazy CB length counter is also introduced to keep track of the number of lazy CBs. [ paulmck: Fix formatting of inline call_rcu_lazy() definition. ] [ paulmck: Apply Zqiang feedback. ] [ paulmck: Apply s/call_rcu_flush/call_rcu_hurry/ feedback from Tejun Heo. ] Suggested-by: Paul McKenney Acked-by: Frederic Weisbecker Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney

rcu: Implement lockdep_rcu_enabled for !CONFIG_DEBUG_LOCK_ALLOC

2022-11-09T17:29:06Z

Provide an implementation for debug_lockdep_rcu_enabled() when CONFIG_DEBUG_LOCK_ALLOC is not enabled. This allows code to check if rcu lockdep debugging is available without needing an extra check if CONFIG_DEBUG_LOCK_ALLOC is enabled. Signed-off-by: John Ogness Signed-off-by: Paul E. McKenney