linux-next.git/kernel/entry, branch master

Merge branch into tip/master: 'sched/core'

2026-10-04T07:26:10+00:00

# New commits in sched/core: 4a3b51aab6e2 ("smpboot: Don't park the thread if work is pending") 40dcc9bdbef3 ("irq_work: Flush lazy work CPU down on PREEMPT_RT") 791b1760accd ("irq_work: Update a comment regarding CPU hotplug invocation") 648d44bda731 ("sched/topology: Add asymmetric SMT packing override") c8fc4136fd3c ("sched/fair: Honor asymmetric SMT priority in idle selection") 53bc5c556b82 ("sched: Set TIF_NEED_RESCHED before calling __trace_set_need_resched()") 4b1f75be23c4 ("sched/core: Fix context analysis errors in non-preferred CPU push") 1fb28c664a19 ("virt/steal_governor: Enable the driver") 27d47ebce4d6 ("virt/steal_governor: Implement steal_governor policy loop") 4b9302d494ff ("virt/steal_governor: Add control knobs for handling steal values") 9a8e740ee9f6 ("virt: Introduce steal governor driver") 68957caaa9c0 ("sched/debug: Add migration stats due to non preferred CPUs") 74699f56ebcf ("sched/core: Push current task from non preferred CPU") 4ee29b029058 ("sched/fair: Load balance only among preferred CPUs") d8a3da0de843 ("sched/core: Try to use a preferred CPU in is_cpu_allowed") 620824516557 ("sysfs: Add preferred CPU file") 518b32bd5bb3 ("cpumask: Introduce cpu_preferred_mask") 06a49ef784ac ("sched/docs: Document cpu_preferred_mask and Preferred CPU concept") cfb463b7172d ("cpumask: Introduce cpumask_intersects_and") a8d0854a76a8 ("sched/cputime: Add kcpustat_field_total helper") be100c77178e ("sched: Add sched_ext hooks for proxy execution") 57c75e3ae38c ("sched: Add helper to block retained proxy donors") a49653d0abeb ("sched/core: Mark wakeups completed through ttwu_runnable()") 8f8c0417e973 ("sched/core: Dequeue waking proxy donors before reset") 313b652837d0 ("sched/core: Drop mutex locks before proxy rescheduling") 627ea30aca3b ("sched/wait: Clarify WF_SYNC wakeup semantics") d2e010082757 ("sched/eevdf: Handle more short slice waking cases") 4bf32ec3327d ("sched/eevdf: Align update_protect_slice to set_protect_slice") aae2a33ea662 ("sched/eevdf: Ensure that vprot will never go above a min slice") c9ce69fc43bd ("sched/fair: Randomize equally shallow slow-path candidates") abe440b3770f ("sched/fair: Drop idle recency from slow-path CPU selection") fbbc63fed0b0 ("sched/core: Remove redundant core_sched_seq") 819224e506bc ("sched/fair: Remove dead code on enqueue_task_fair()") c72945693b90 ("sched: Restart fair hrtick after same-task repicks") a9b3c7570564 ("sched/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in the header") e81ee0630837 ("sched/fair: Reset NUMA fault locality after scan period update") ef9293b3b797 ("sched: dynamic: Fix preemption model strings") 879eaa76e608 ("sched: Remove unneeded function type cast in do_balance_callbacks()") f549101187c8 ("sched/deadline: check start_dl_timer expiry with ktime_before()") 2a672daa4b27 ("sched/feat: Use the new static key API for sched_feat") a5576ebce920 ("sched: Convert paravirt_steal to new static key APIs") 9650ce11f2e3 ("sched: dynamic: Simplify preempt model accessors") 5b9a28eeed37 ("sched: dynamic: Remove HAVE_PREEMPT_DYNAMIC_{CALL,KEY}") aa4178f63847 ("sched: dynamic: Simplify irqentry_exit_cond_resched()") b9d267b9d632 ("sched: dynamic: Simplify preempt_schedule{,_notrace}()") 88e0b3bb9930 ("sched: dynamic: Simplify {cond,might}_resched()") d3d16750693b ("sched: dynamic: Make PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY") 772d9ffbfd26 ("sched: Migrate whole chain in proxy_migrate_task()") 6b73a09e943f ("sched: Break out core of attach_tasks() helper into sched.h") 1f8805138593 ("sched: Switch rq->next_class in proxy_reset_donor()") 09351db90a28 ("sched/core: Don't proxy-exec unmatched cookie lock owners") 9be817f991e2 ("sched/core: Avoid migrating blocked_on tasks") 3dd95f077371 ("sched/core: Don't steal a proxy-exec donor") Signed-off-by: Ingo Molnar

syscall_user_dispatch: Use CONFIG_SYSCTL for sysctl guard

2026-09-07T12:00:56+00:00

Commit 8d75c338f0bc ("sysctl: remove CONFIG_PROC_SYSCTL, it just mirrors CONFIG_SYSCTL") removed CONFIG_PROC_SYSCTL, but the sysctl added by commit 5b6e32ba7b59 ("syscall_user_dispatch: Add kernel.syscall_user_dispatch sysctl") is still guarded by it. Now that both commits are merged, kernel.syscall_user_dispatch is no longer registered. syscall_user_dispatch_allowed defaults to true. SUD therefore remains available, but administrators cannot disable new activations. Use CONFIG_SYSCTL for the guard and documentation. Fixes: 5b6e32ba7b59 ("syscall_user_dispatch: Add kernel.syscall_user_dispatch sysctl") Assisted-by: Codex:gpt-5.6-sol Acked-by: Oleg Nesterov Reviewed-by: Joel Granados Signed-off-by: Karl Mehltretter Acked-by: Randy Dunlap Reviewed-by: Bradley Morgan Signed-off-by: Joel Granados

sched: dynamic: Simplify irqentry_exit_cond_resched()

2026-09-02T07:37:23+00:00

PREEMPT_DYNAMIC is now limited to the FULL and LAZY preemption models. In either model, irqentry_exit_cond_resched() is always called and never disabled. Remove the unnecessary code for this when PREEMPT_DYNAMIC is selected. Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Shrikanth Hegde Reviewed-by: Jinjie Ruan Tested-by: Mete Durlu Tested-by: Shrikanth Hegde Tested-by: Jinjie Ruan Link: https://patch.msgid.link/20260803191731.3244294-5-mark.rutland@arm.com

entry: Rework trace_syscall_enter()

2026-07-20T18:38:40+00:00

Reread the syscall number from pt_regs and stop returning the eventually modified syscall number. That moves the reread to the end of syscall_trace_enter() and prepares for moving it to the call site. No functional change. Signed-off-by: Thomas Gleixner Tested-by: Michal Suchánek Reviewed-by: Jinjie Ruan Link: https://patch.msgid.link/20260712141346.639115923@kernel.org

entry: Rework syscall_audit_enter()

2026-07-20T18:38:40+00:00

Move it out of line and let it reread the syscall number on it's own. That makes the low level entry code denser and allows to move the reread to the call site of syscall_trace_enter() once the tracer is fixed up. To prevent the compiler from putting audit_context() out of line and thereby breaking dead code elimination, mark audit_context() __always_inline. Signed-off-by: Thomas Gleixner Tested-by: Michal Suchánek Reviewed-by: Jinjie Ruan Link: https://patch.msgid.link/20260712141346.576865340@kernel.org

syscall_user_dispatch: Add kernel.syscall_user_dispatch sysctl

2026-07-08T08:22:00+00:00

Add a matching sysctl to go with CONFIG_SYSCALL_USER_DISPATCH. kernel.syscall_user_dispatch (default 1 - allow) controls whether userspace may arm syscall user dispatch (both via prctl and ptrace). Disarming is always permitted - same semantics as comparable knobs. Disabling while a task has armed syscall user dispatch does not cause it to become inactive - instead it remains active until the user attempts to disable/re-enable via prctl or ptrace. On the next attempt to re-enable, the prctl/ptrace call fails gracefully. The alternative would cause programs translating non-linux syscalls to interpret those syscalls as linux syscalls, resulting in undefined userland behavior. Signed-off-by: Gregory Price Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260706140020.873735-3-gourry@gourry.net

syscall_user_dispatch: Make it configurable in Kconfig

2026-07-08T08:22:00+00:00

Syscall User Dispatch is presently built under CONFIG_GENERIC_SYSCALL and cannot be disabled independently. Add CONFIG_SYSCALL_USER_DISPATCH to make it an optional feature. Signed-off-by: Gregory Price Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260706140020.873735-2-gourry@gourry.net

futex: Provide infrastructure to plug the non contended robust futex unlock race

2026-06-03T09:38:52+00:00

When the FUTEX_ROBUST_UNLOCK mechanism is used for unlocking (PI-)futexes, then the unlock sequence in user space looks like this: 1) robust_list_set_op_pending(mutex); 2) robust_list_remove(mutex); lval = gettid(); 3) if (atomic_try_cmpxchg(&mutex->lock, lval, 0)) 4) robust_list_clear_op_pending(); else 5) sys_futex(OP | FUTEX_ROBUST_UNLOCK, ....); That still leaves a minimal race window between #3 and #4 where the mutex could be acquired by some other task, which observes that it is the last user and: 1) unmaps the mutex memory 2) maps a different file, which ends up covering the same address When then the original task exits before reaching #5 then the kernel robust list handling observes the pending op entry and tries to fix up user space. In case that the newly mapped data contains the TID of the exiting thread at the address of the mutex/futex the kernel will set the owner died bit in that memory and therefore corrupt unrelated data. On X86 this boils down to this simplified assembly sequence: mov %esi,%eax // Load TID into EAX xor %ecx,%ecx // Set ECX to 0 #3 lock cmpxchg %ecx,(%rdi) // Try the TID -> 0 transition .Lstart: jnz .Lend #4 movq %rcx,(%rdx) // Clear list_op_pending .Lend: If the cmpxchg() succeeds and the task is interrupted before it can clear list_op_pending in the robust list head (#4) and the task crashes in a signal handler or gets killed then it ends up in do_exit() and subsequently in the robust list handling, which then might run into the unmap/map issue described above. This is only relevant when user space was interrupted and a signal is pending. The fix-up has to be done before signal delivery is attempted because: 1) The signal might be fatal so get_signal() ends up in do_exit() 2) The signal handler might crash or the task is killed before returning from the handler. At that point the instruction pointer in pt_regs is not longer the instruction pointer of the initially interrupted unlock sequence. The right place to handle this is in __exit_to_user_mode_loop() before invoking arch_do_signal_or_restart() as this covers obviously both scenarios. As this is only relevant when the task was interrupted in user space, this is tied to RSEQ and the generic entry code as RSEQ keeps track of user space interrupts unconditionally even if the task does not have a RSEQ region installed. That makes the decision very lightweight: if (current->rseq.user_irq && within(regs, csr->unlock_ip_range)) futex_fixup_robust_unlock(regs, csr); futex_fixup_robust_unlock() then invokes a architecture specific function to return the pending op pointer or NULL. The function evaluates the register content to decide whether the pending ops pointer in the robust list head needs to be cleared. Assuming the above unlock sequence, then on x86 this decision is the trivial evaluation of the zero flag: return regs->eflags & X86_EFLAGS_ZF ? regs->dx : NULL; Other architectures might need to do more complex evaluations due to LLSC, but the approach is valid in general. The size of the pointer is determined from the matching range struct, which covers both 32-bit and 64-bit builds including COMPAT. The unlock sequence is going to be placed in the VDSO so that the kernel can keep everything synchronized, especially the register usage. The resulting code sequence for user space is: if (__vdso_futex_robust_list$SZ_try_unlock(lock, tid, &pending_op) != tid) err = sys_futex($OP | FUTEX_ROBUST_UNLOCK,....); Both the VDSO unlock and the kernel side unlock ensure that the pending_op pointer is always cleared when the lock becomes unlocked. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://patch.msgid.link/20260602090535.773669210@kernel.org

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

2026-04-14T23:48:56+00:00

Pull arm64 updates from Catalin Marinas: "The biggest changes are MPAM enablement in drivers/resctrl and new PMU support under drivers/perf. On the core side, FEAT_LSUI lets futex atomic operations with EL0 permissions, avoiding PAN toggling. The rest is mostly TLB invalidation refactoring, further generic entry work, sysreg updates and a few fixes. Core features: - Add support for FEAT_LSUI, allowing futex atomic operations without toggling Privileged Access Never (PAN) - Further refactor the arm64 exception handling code towards the generic entry infrastructure - Optimise __READ_ONCE() with CONFIG_LTO=y and allow alias analysis through it Memory management: - Refactor the arm64 TLB invalidation API and implementation for better control over barrier placement and level-hinted invalidation - Enable batched TLB flushes during memory hot-unplug - Fix rodata=full block mapping support for realm guests (when BBML2_NOABORT is available) Perf and PMU: - Add support for a whole bunch of system PMUs featured in NVIDIA's Tegra410 SoC (cspmu extensions for the fabric and PCIe, new drivers for CPU/C2C memory latency PMUs) - Clean up iomem resource handling in the Arm CMN driver - Fix signedness handling of AA64DFR0.{PMUVer,PerfMon} MPAM (Memory Partitioning And Monitoring): - Add architecture context-switch and hiding of the feature from KVM - Add interface to allow MPAM to be exposed to user-space using resctrl - Add errata workaround for some existing platforms - Add documentation for using MPAM and what shape of platforms can use resctrl Miscellaneous: - Check DAIF (and PMR, where relevant) at task-switch time - Skip TFSR_EL1 checks and barriers in synchronous MTE tag check mode (only relevant to asynchronous or asymmetric tag check modes) - Remove a duplicate allocation in the kexec code - Remove redundant save/restore of SCS SP on entry to/from EL0 - Generate the KERNEL_HWCAP_ definitions from the arm64 hwcap descriptions - Add kselftest coverage for cmpbr_sigill() - Update sysreg definitions" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (109 commits) arm64: rsi: use linear-map alias for realm config buffer arm64: Kconfig: fix duplicate word in CMDLINE help text arm64: mte: Skip TFSR_EL1 checks and barriers in synchronous tag check mode arm64/sysreg: Update ID_AA64SMFR0_EL1 description to DDI0601 2025-12 arm64/sysreg: Update ID_AA64ZFR0_EL1 description to DDI0601 2025-12 arm64/sysreg: Update ID_AA64FPFR0_EL1 description to DDI0601 2025-12 arm64/sysreg: Update ID_AA64ISAR2_EL1 description to DDI0601 2025-12 arm64/sysreg: Update ID_AA64ISAR0_EL1 description to DDI0601 2025-12 arm64/hwcap: Generate the KERNEL_HWCAP_ definitions for the hwcaps arm64: kexec: Remove duplicate allocation for trans_pgd ACPI: AGDI: fix missing newline in error message arm64: Check DAIF (and PMR) at task-switch time arm64: entry: Use split preemption logic arm64: entry: Use irqentry_{enter_from,exit_to}_kernel_mode() arm64: entry: Consistently prefix arm64-specific wrappers arm64: entry: Don't preempt with SError or Debug masked entry: Split preemption from irqentry_exit_to_kernel_mode() entry: Split kernel mode logic from irqentry_{enter,exit}() entry: Move irqentry_enter() prototype later entry: Remove local_irq_{enable,disable}_exit_to_user() ...

entry: Split kernel mode logic from irqentry_{enter,exit}()

2026-04-08T09:43:32+00:00

The generic irqentry code has entry/exit functions specifically for exceptions taken from user mode, but doesn't have entry/exit functions specifically for exceptions taken from kernel mode. It would be helpful to have separate entry/exit functions specifically for exceptions taken from kernel mode. This would make the structure of the entry code more consistent, and would make it easier for architectures to manage logic specific to exceptions taken from kernel mode. Move the logic specific to kernel mode out of irqentry_enter() and irqentry_exit() into new irqentry_enter_from_kernel_mode() and irqentry_exit_to_kernel_mode() functions. These are marked __always_inline and placed in irq-entry-common.h, as with irqentry_enter_from_user_mode() and irqentry_exit_to_user_mode(), so that they can be inlined into architecture-specific wrappers. The existing out-of-line irqentry_enter() and irqentry_exit() functions retained as callers of the new functions. The lockdep assertion from irqentry_exit() is moved into irqentry_exit_to_user_mode() and irqentry_exit_to_kernel_mode(). This was previously missing from irqentry_exit_to_user_mode() when called directly, and any new lockdep assertion failure relating from this change is a latent bug. Aside from the lockdep change noted above, there should be no functional change as a result of this change. [ tglx: Updated kernel doc ] Signed-off-by: Mark Rutland Signed-off-by: Thomas Gleixner Reviewed-by: Jinjie Ruan Acked-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260407131650.3813777-5-mark.rutland@arm.com