user/sven/linux.git/kernel/sys.c, branch v6.12.47

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

Merge patch series "riscv: Create and document PR_RISCV_SET_ICACHE_FLUSH_CTX prctl"

2024-04-30T17:35:42Z

Charlie Jenkins says: Improve the performance of icache flushing by creating a new prctl flag PR_RISCV_SET_ICACHE_FLUSH_CTX. The interface is left generic to allow for future expansions such as with the proposed J extension [1]. Documentation is also provided to explain the use case. Patch sent to add PR_RISCV_SET_ICACHE_FLUSH_CTX to man-pages [2]. [1] https://github.com/riscv/riscv-j-extension [2] https://lore.kernel.org/linux-man/20240124-fencei_prctl-v1-1-0bddafcef331@rivosinc.com * b4-shazam-merge: cpumask: Add assign cpu documentation: Document PR_RISCV_SET_ICACHE_FLUSH_CTX prctl riscv: Include riscv_set_icache_flush_ctx prctl riscv: Remove unnecessary irqflags processor.h include Link: https://lore.kernel.org/r/20240312-fencei-v13-0-4b6bdc2bbf32@rivosinc.com Signed-off-by: Palmer Dabbelt

riscv: Include riscv_set_icache_flush_ctx prctl

2024-04-18T15:10:58Z

Support new prctl with key PR_RISCV_SET_ICACHE_FLUSH_CTX to enable optimization of cross modifying code. This prctl enables userspace code to use icache flushing instructions such as fence.i with the guarantee that the icache will continue to be clean after thread migration. Signed-off-by: Charlie Jenkins Reviewed-by: Atish Patra Reviewed-by: Alexandre Ghiti Reviewed-by: Samuel Holland Link: https://lore.kernel.org/r/20240312-fencei-v13-2-4b6bdc2bbf32@rivosinc.com Signed-off-by: Palmer Dabbelt

prctl: generalize PR_SET_MDWE support check to be per-arch

2024-03-26T18:07:22Z

Patch series "ARM: prctl: Reject PR_SET_MDWE where not supported". I noticed after a recent kernel update that my ARM926 system started segfaulting on any execve() after calling prctl(PR_SET_MDWE). After some investigation it appears that ARMv5 is incapable of providing the appropriate protections for MDWE, since any readable memory is also implicitly executable. The prctl_set_mdwe() function already had some special-case logic added disabling it on PARISC (commit 793838138c15, "prctl: Disable prctl(PR_SET_MDWE) on parisc"); this patch series (1) generalizes that check to use an arch_*() function, and (2) adds a corresponding override for ARM to disable MDWE on pre-ARMv6 CPUs. With the series applied, prctl(PR_SET_MDWE) is rejected on ARMv5 and subsequent execve() calls (as well as mmap(PROT_READ|PROT_WRITE)) can succeed instead of unconditionally failing; on ARMv6 the prctl works as it did previously. [0] https://lore.kernel.org/all/2023112456-linked-nape-bf19@gregkh/ This patch (of 2): There exist systems other than PARISC where MDWE may not be feasible to support; rather than cluttering up the generic code with additional arch-specific logic let's add a generic function for checking MDWE support and allow each arch to override it as needed. Link: https://lkml.kernel.org/r/20240227013546.15769-4-zev@bewilderbeest.net Link: https://lkml.kernel.org/r/20240227013546.15769-5-zev@bewilderbeest.net Signed-off-by: Zev Weiss Acked-by: Helge Deller [parisc] Cc: Borislav Petkov Cc: David Hildenbrand Cc: Florent Revest Cc: "James E.J. Bottomley" Cc: Josh Triplett Cc: Kees Cook Cc: Miguel Ojeda Cc: Mike Rapoport (IBM) Cc: Oleg Nesterov Cc: Ondrej Mosnacek Cc: Rick Edgecombe Cc: Russell King (Oracle) Cc: Sam James Cc: Stefan Roesch Cc: Yang Shi Cc: Yin Fengwei Cc: [6.3+] Signed-off-by: Andrew Morton

getrusage: use sig->stats_lock rather than lock_task_sighand()

2024-02-08T05:20:32Z

lock_task_sighand() can trigger a hard lockup. If NR_CPUS threads call getrusage() at the same time and the process has NR_THREADS, spin_lock_irq will spin with irqs disabled O(NR_CPUS * NR_THREADS) time. Change getrusage() to use sig->stats_lock, it was specifically designed for this type of use. This way it runs lockless in the likely case. TODO: - Change do_task_stat() to use sig->stats_lock too, then we can remove spin_lock_irq(siglock) in wait_task_zombie(). - Turn sig->stats_lock into seqcount_rwlock_t, this way the readers in the slow mode won't exclude each other. See https://lore.kernel.org/all/20230913154907.GA26210@redhat.com/ - stats_lock has to disable irqs because ->siglock can be taken in irq context, it would be very nice to change __exit_signal() to avoid the siglock->stats_lock dependency. Link: https://lkml.kernel.org/r/20240122155053.GA26214@redhat.com Signed-off-by: Oleg Nesterov Reported-by: Dylan Hatch Tested-by: Dylan Hatch Cc: Eric W. Biederman Cc: Signed-off-by: Andrew Morton