user/sven/linux.git/kernel/sys.c, branch v6.14.9

tracing: Add task_prctl_unknown tracepoint

2024-12-23T04:28:11Z

prctl() is a complex syscall which multiplexes its functionality based on a large set of PR_* options. Currently we count 64 such options. The return value of unknown options is -EINVAL, and doesn't distinguish from known options that were passed invalid args that also return -EINVAL. To understand if programs are attempting to use prctl() options not yet available on the running kernel, provide the task_prctl_unknown tracepoint. Note, this tracepoint is in an unlikely cold path, and would therefore be suitable for continuous monitoring (e.g. via perf_event_open). While the above is likely the simplest usecase, additionally this tracepoint can help unlock some testing scenarios (where probing sys_enter or sys_exit causes undesirable performance overheads): a. unprivileged triggering of a test module: test modules may register a probe to be called back on task_prctl_unknown, and pick a very large unknown prctl() option upon which they perform a test function for an unprivileged user; b. unprivileged triggering of an eBPF program function: similar as idea (a). Example trace_pipe output: test-380 [001] ..... 78.142904: task_prctl_unknown: option=1234 arg2=101 arg3=102 arg4=103 arg5=104 Signed-off-by: Marco Elver Reviewed-by: Alexander Potapenko Link: https://lore.kernel.org/r/20241108113455.2924361-1-elver@google.com Signed-off-by: Kees Cook

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2024-11-19T02:10:37Z

Pull arm64 updates from Catalin Marinas: - Support for running Linux in a protected VM under the Arm Confidential Compute Architecture (CCA) - Guarded Control Stack user-space support. Current patches follow the x86 ABI of implicitly creating a shadow stack on clone(). Subsequent patches (already on the list) will add support for clone3() allowing finer-grained control of the shadow stack size and placement from libc - AT_HWCAP3 support (not running out of HWCAP2 bits yet but we are getting close with the upcoming dpISA support) - Other arch features: - In-kernel use of the memcpy instructions, FEAT_MOPS (previously only exposed to user; uaccess support not merged yet) - MTE: hugetlbfs support and the corresponding kselftests - Optimise CRC32 using the PMULL instructions - Support for FEAT_HAFT enabling ARCH_HAS_NONLEAF_PMD_YOUNG - Optimise the kernel TLB flushing to use the range operations - POE/pkey (permission overlays): further cleanups after bringing the signal handler in line with the x86 behaviour for 6.12 - arm64 perf updates: - Support for the NXP i.MX91 PMU in the existing IMX driver - Support for Ampere SoCs in the Designware PCIe PMU driver - Support for Marvell's 'PEM' PCIe PMU present in the 'Odyssey' SoC - Support for Samsung's 'Mongoose' CPU PMU - Support for PMUv3.9 finer-grained userspace counter access control - Switch back to platform_driver::remove() now that it returns 'void' - Add some missing events for the CXL PMU driver - Miscellaneous arm64 fixes/cleanups: - Page table accessors cleanup: type updates, drop unused macros, reorganise arch_make_huge_pte() and clean up pte_mkcont(), sanity check addresses before runtime P4D/PUD folding - Command line override for ID_AA64MMFR0_EL1.ECV (advertising the FEAT_ECV for the generic timers) allowing Linux to boot with firmware deployments that don't set SCTLR_EL3.ECVEn - ACPI/arm64: tighten the check for the array of platform timer structures and adjust the error handling procedure in gtdt_parse_timer_block() - Optimise the cache flush for the uprobes xol slot (skip if no change) and other uprobes/kprobes cleanups - Fix the context switching of tpidrro_el0 when kpti is enabled - Dynamic shadow call stack fixes - Sysreg updates - Various arm64 kselftest improvements * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (168 commits) arm64: tls: Fix context-switching of tpidrro_el0 when kpti is enabled kselftest/arm64: Try harder to generate different keys during PAC tests kselftest/arm64: Don't leak pipe fds in pac.exec_sign_all() arm64/ptrace: Clarify documentation of VL configuration via ptrace kselftest/arm64: Corrupt P0 in the irritator when testing SSVE acpi/arm64: remove unnecessary cast arm64/mm: Change protval as 'pteval_t' in map_range() kselftest/arm64: Fix missing printf() argument in gcs/gcs-stress.c kselftest/arm64: Add FPMR coverage to fp-ptrace kselftest/arm64: Expand the set of ZA writes fp-ptrace does kselftets/arm64: Use flag bits for features in fp-ptrace assembler code kselftest/arm64: Enable build of PAC tests with LLVM=1 kselftest/arm64: Check that SVCR is 0 in signal handlers selftests/mm: Fix unused function warning for aarch64_write_signal_pkey() kselftest/arm64: Fix printf() compiler warnings in the arm64 syscall-abi.c tests kselftest/arm64: Fix printf() warning in the arm64 MTE prctl() test kselftest/arm64: Fix printf() compiler warnings in the arm64 fp tests kselftest/arm64: Fix build with stricter assemblers arm64/scs: Drop unused prototype __pi_scs_patch_vmlinux() arm64/scs: Deal with 64-bit relative offsets in FDE frames ...

fdget(), trivial conversions

2024-11-03T06:28:06Z

fdget() is the first thing done in scope, all matching fdput() are immediately followed by leaving the scope. Reviewed-by: Christian Brauner Signed-off-by: Al Viro

prctl: arch-agnostic prctl for shadow stack

2024-10-04T11:04:33Z

Three architectures (x86, aarch64, riscv) have announced support for shadow stacks with fairly similar functionality. While x86 is using arch_prctl() to control the functionality neither arm64 nor riscv uses that interface so this patch adds arch-agnostic prctl() support to get and set status of shadow stacks and lock the current configuation to prevent further changes, with support for turning on and off individual subfeatures so applications can limit their exposure to features that they do not need. The features are: - PR_SHADOW_STACK_ENABLE: Tracking and enforcement of shadow stacks, including allocation of a shadow stack if one is not already allocated. - PR_SHADOW_STACK_WRITE: Writes to specific addresses in the shadow stack. - PR_SHADOW_STACK_PUSH: Push additional values onto the shadow stack. These features are expected to be inherited by new threads and cleared on exec(), unknown features should be rejected for enable but accepted for locking (in order to allow for future proofing). This is based on a patch originally written by Deepak Gupta but modified fairly heavily, support for indirect landing pads is removed, additional modes added and the locking interface reworked. The set status prctl() is also reworked to just set flags, if setting/reading the shadow stack pointer is required this could be a separate prctl. Reviewed-by: Thiago Jung Bauermann Reviewed-by: Catalin Marinas Acked-by: Yury Khrustalev Signed-off-by: Mark Brown Reviewed-by: Deepak Gupta Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-4-222b78d87eee@kernel.org Signed-off-by: Catalin Marinas

Merge tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-09-23T16:35:36Z

Pull 'struct fd' updates from Al Viro: "Just the 'struct fd' layout change, with conversion to accessor helpers" * tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: add struct fd constructors, get rid of __to_fd() struct fd: representation change introduce fd_file(), convert all accessors to it.

Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-09-19T13:55:58Z

Pull scheduler updates from Ingo Molnar: - Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's last major contribution to the kernel: "SCHED_DEADLINE servers can help fixing starvation issues of low priority tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU cycles. Today we have RT Throttling; DEADLINE servers should be able to replace and improve that." (Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef Esmat, Huang Shijie) - Preparatory changes for sched_ext integration: - Use set_next_task(.first) where required - Fix up set_next_task() implementations - Clean up DL server vs. core sched - Split up put_prev_task_balance() - Rework pick_next_task() - Combine the last put_prev_task() and the first set_next_task() - Rework dl_server - Add put_prev_task(.next) (Peter Zijlstra, with a fix by Tejun Heo) - Complete the EEVDF transition and refine EEVDF scheduling: - Implement delayed dequeue - Allow shorter slices to wakeup-preempt - Use sched_attr::sched_runtime to set request/slice suggestion - Document the new feature flags - Remove unused and duplicate-functionality fields - Simplify & unify pick_next_task_fair() - Misc debuggability enhancements (Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin Schneider and Chuyi Zhou) - Initialize the vruntime of a new task when it is first enqueued, resulting in significant decrease in latency of newly woken tasks (Zhang Qiao) - Introduce SM_IDLE and an idle re-entry fast-path in __schedule() (K Prateek Nayak, Peter Zijlstra) - Clean up and clarify the usage of Clean up usage of rt_task() (Qais Yousef) - Preempt SCHED_IDLE entities in strict cgroup hierarchies (Tianchen Ding) - Clarify the documentation of time units for deadline scheduler parameters (Christian Loehle) - Remove the HZ_BW chicken-bit feature flag introduced a year ago, the original change seems to be working fine (Phil Auld) - Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie, Peilin He, Qais Yousefm and Vincent Guittot) * tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits) sched/cpufreq: Use NSEC_PER_MSEC for deadline task cpufreq/cppc: Use NSEC_PER_MSEC for deadline task sched/deadline: Clarify nanoseconds in uapi sched/deadline: Convert schedtool example to chrt sched/debug: Fix the runnable tasks output sched: Fix sched_delayed vs sched_core kernel/sched: Fix util_est accounting for DELAY_DEQUEUE kthread: Fix task state in kthread worker if being frozen sched/pelt: Use rq_clock_task() for hw_pressure sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule() sched: Add put_prev_task(.next) sched: Rework dl_server sched: Combine the last put_prev_task() and the first set_next_task() sched: Rework pick_next_task() sched: Split up put_prev_task_balance() sched: Clean up DL server vs core sched sched: Fixup set_next_task() implementations sched: Use set_next_task(.first) where required sched/fair: Properly deactivate sched_delayed task upon class change ...

hrtimer: Use and report correct timerslack values for realtime tasks

2024-08-23T18:13:02Z

The timerslack_ns setting is used to specify how much the hardware timers should be delayed, to potentially dispatch multiple timers in a single interrupt. This is a performance optimization. Timers of realtime tasks (having a realtime scheduling policy) should not be delayed. This logic was inconsitently applied to the hrtimers, leading to delays of realtime tasks which used timed waits for events (e.g. condition variables). Due to the downstream override of the slack for rt tasks, the procfs reported incorrect (non-zero) timerslack_ns values. This is changed by setting the timer_slack_ns task attribute to 0 for all tasks with a rt policy. By that, downstream users do not need to specially handle rt tasks (w.r.t. the slack), and the procfs entry shows the correct value of "0". Setting non-zero slack values (either via procfs or PR_SET_TIMERSLACK) on tasks with a rt policy is ignored, as stated in "man 2 PR_SET_TIMERSLACK": Timer slack is not applied to threads that are scheduled under a real-time scheduling policy (see sched_setscheduler(2)). The special handling of timerslack on rt tasks in downstream users is removed as well. Signed-off-by: Felix Moessbauer Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20240814121032.368444-2-felix.moessbauer@siemens.com

introduce fd_file(), convert all accessors to it.

2024-08-13T02:00:43Z

For any changes of struct fd representation we need to turn existing accesses to fields into calls of wrappers. Accesses to struct fd::flags are very few (3 in linux/file.h, 1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in explicit initializers). Those can be dealt with in the commit converting to new layout; accesses to struct fd::file are too many for that. This commit converts (almost) all of f.file to fd_file(f). It's not entirely mechanical ('file' is used as a member name more than just in struct fd) and it does not even attempt to distinguish the uses in pointer context from those in boolean context; the latter will be eventually turned into a separate helper (fd_empty()). NOTE: mass conversion to fd_empty(), tempting as it might be, is a bad idea; better do that piecewise in commit that convert from fdget...() to CLASS(...). [conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c caught by git; fs/stat.c one got caught by git grep] [fs/xattr.c conflict] Reviewed-by: Christian Brauner Signed-off-by: Al Viro

Merge tag 'riscv-for-linus-6.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2024-05-22T16:56:00Z

Pull RISC-V updates from Palmer Dabbelt: - Add byte/half-word compare-and-exchange, emulated via LR/SC loops - Support for Rust - Support for Zihintpause in hwprobe - Add PR_RISCV_SET_ICACHE_FLUSH_CTX prctl() - Support lockless lockrefs * tag 'riscv-for-linus-6.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (42 commits) riscv: defconfig: Enable CONFIG_CLK_SOPHGO_CV1800 riscv: select ARCH_HAS_FAST_MULTIPLIER riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required riscv: Annotate pgtable_l{4,5}_enabled with __ro_after_init riscv: Remove redundant CONFIG_64BIT from pgtable_l{4,5}_enabled riscv: mm: Always use an ASID to flush mm contexts riscv: mm: Preserve global TLB entries when switching contexts riscv: mm: Make asid_bits a local variable riscv: mm: Use a fixed layout for the MM context ID riscv: mm: Introduce cntx2asid/cntx2version helper macros riscv: Avoid TLB flush loops when affected by SiFive CIP-1200 riscv: Apply SiFive CIP-1200 workaround to single-ASID sfence.vma riscv: mm: Combine the SMP and UP TLB flush code riscv: Only send remote fences when some other CPU is online riscv: mm: Broadcast kernel TLB flushes only when needed riscv: Use IPIs for remote cache/TLB flushes by default riscv: Factor out page table TLB synchronization riscv: Flush the instruction cache during SMP bringup riscv: hwprobe: export Zihintpause ISA extension riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code ...

powerpc/dexcr: Add DEXCR prctl interface

2024-05-06T12:04:31Z

Now that we track a DEXCR on a per-task basis, individual tasks are free to configure it as they like. The interface is a pair of getter/setter prctl's that work on a single aspect at a time (multiple aspects at once is more difficult if there are different rules applied for each aspect, now or in future). The getter shows the current state of the process config, and the setter allows setting/clearing the aspect. Signed-off-by: Benjamin Gray [mpe: Account for PR_RISCV_SET_ICACHE_FLUSH_CTX, shrink some longs lines] Signed-off-by: Michael Ellerman Link: https://msgid.link/20240417112325.728010-5-bgray@linux.ibm.com