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2023-11-02Merge tag 'asm-generic-6.7' of ↵Linus Torvalds1-13/+4
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull ia64 removal and asm-generic updates from Arnd Bergmann: - The ia64 architecture gets its well-earned retirement as planned, now that there is one last (mostly) working release that will be maintained as an LTS kernel. - The architecture specific system call tables are updated for the added map_shadow_stack() syscall and to remove references to the long-gone sys_lookup_dcookie() syscall. * tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: hexagon: Remove unusable symbols from the ptrace.h uapi asm-generic: Fix spelling of architecture arch: Reserve map_shadow_stack() syscall number for all architectures syscalls: Cleanup references to sys_lookup_dcookie() Documentation: Drop or replace remaining mentions of IA64 lib/raid6: Drop IA64 support Documentation: Drop IA64 from feature descriptions kernel: Drop IA64 support from sig_fault handlers arch: Remove Itanium (IA-64) architecture
2023-10-31Merge tag 'sched-core-2023-10-28' of ↵Linus Torvalds8-10/+35
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "Fair scheduler (SCHED_OTHER) improvements: - Remove the old and now unused SIS_PROP code & option - Scan cluster before LLC in the wake-up path - Use candidate prev/recent_used CPU if scanning failed for cluster wakeup NUMA scheduling improvements: - Improve the VMA access-PID code to better skip/scan VMAs - Extend tracing to cover VMA-skipping decisions - Improve/fix the recently introduced sched_numa_find_nth_cpu() code - Generalize numa_map_to_online_node() Energy scheduling improvements: - Remove the EM_MAX_COMPLEXITY limit - Add tracepoints to track energy computation - Make the behavior of the 'sched_energy_aware' sysctl more consistent - Consolidate and clean up access to a CPU's max compute capacity - Fix uclamp code corner cases RT scheduling improvements: - Drive dl_rq->overloaded with dl_rq->pushable_dl_tasks updates - Drive the ->rto_mask with rt_rq->pushable_tasks updates Scheduler scalability improvements: - Rate-limit updates to tg->load_avg - On x86 disable IBRS when CPU is offline to improve single-threaded performance - Micro-optimize in_task() and in_interrupt() - Micro-optimize the PSI code - Avoid updating PSI triggers and ->rtpoll_total when there are no state changes Core scheduler infrastructure improvements: - Use saved_state to reduce some spurious freezer wakeups - Bring in a handful of fast-headers improvements to scheduler headers - Make the scheduler UAPI headers more widely usable by user-space - Simplify the control flow of scheduler syscalls by using lock guards - Fix sched_setaffinity() vs. CPU hotplug race Scheduler debuggability improvements: - Disallow writing invalid values to sched_rt_period_us - Fix a race in the rq-clock debugging code triggering warnings - Fix a warning in the bandwidth distribution code - Micro-optimize in_atomic_preempt_off() checks - Enforce that the tasklist_lock is held in for_each_thread() - Print the TGID in sched_show_task() - Remove the /proc/sys/kernel/sched_child_runs_first sysctl ... and misc cleanups & fixes" * tag 'sched-core-2023-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (82 commits) sched/fair: Remove SIS_PROP sched/fair: Use candidate prev/recent_used CPU if scanning failed for cluster wakeup sched/fair: Scan cluster before scanning LLC in wake-up path sched: Add cpus_share_resources API sched/core: Fix RQCF_ACT_SKIP leak sched/fair: Remove unused 'curr' argument from pick_next_entity() sched/nohz: Update comments about NEWILB_KICK sched/fair: Remove duplicate #include sched/psi: Update poll => rtpoll in relevant comments sched: Make PELT acronym definition searchable sched: Fix stop_one_cpu_nowait() vs hotplug sched/psi: Bail out early from irq time accounting sched/topology: Rename 'DIE' domain to 'PKG' sched/psi: Delete the 'update_total' function parameter from update_triggers() sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes sched/headers: Remove comment referring to rq::cpu_load, since this has been removed sched/numa: Complete scanning of inactive VMAs when there is no alternative sched/numa: Complete scanning of partial VMAs regardless of PID activity sched/numa: Move up the access pid reset logic sched/numa: Trace decisions related to skipping VMAs ...
2023-10-24sched/fair: Remove SIS_PROPPeter Zijlstra1-2/+0
SIS_UTIL seems to work well, lets remove the old thing. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20231020134337.GD33965@noisy.programming.kicks-ass.net
2023-10-24sched: Add cpus_share_resources APIBarry Song2-1/+14
Add cpus_share_resources() API. This is the preparation for the optimization of select_idle_cpu() on platforms with cluster scheduler level. On a machine with clusters cpus_share_resources() will test whether two cpus are within the same cluster. On a non-cluster machine it will behaves the same as cpus_share_cache(). So we use "resources" here for cache resources. Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-and-reviewed-by: Chen Yu <yu.c.chen@intel.com> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Link: https://lkml.kernel.org/r/20231019033323.54147-2-yangyicong@huawei.com
2023-10-11sched/numa: Complete scanning of inactive VMAs when there is no alternativeMel Gorman1-0/+1
VMAs are skipped if there is no recent fault activity but this represents a chicken-and-egg problem as there may be no fault activity if the PTEs are never updated to trap NUMA hints. There is an indirect reliance on scanning to be forced early in the lifetime of a task but this may fail to detect changes in phase behaviour. Force inactive VMAs to be scanned when all other eligible VMAs have been updated within the same scan sequence. Test results in general look good with some changes in performance, both negative and positive, depending on whether the additional scanning and faulting was beneficial or not to the workload. The autonuma benchmark workload NUMA01_THREADLOCAL was picked for closer examination. The workload creates two processes with numerous threads and thread-local storage that is zero-filled in a loop. It exercises the corner case where unrelated threads may skip VMAs that are thread-local to another thread and still has some VMAs that inactive while the workload executes. The VMA skipping activity frequency with and without the patch: 6.6.0-rc2-sched-numabtrace-v1 ============================= 649 reason=scan_delay 9,094 reason=unsuitable 48,915 reason=shared_ro 143,919 reason=inaccessible 193,050 reason=pid_inactive 6.6.0-rc2-sched-numabselective-v1 ============================= 146 reason=seq_completed 622 reason=ignore_pid_inactive 624 reason=scan_delay 6,570 reason=unsuitable 16,101 reason=shared_ro 27,608 reason=inaccessible 41,939 reason=pid_inactive Note that with the patch applied, the PID activity is ignored (ignore_pid_inactive) to ensure a VMA with some activity is completely scanned. In addition, a small number of VMAs are scanned when no other eligible VMA is available during a single scan window (seq_completed). The number of times a VMA is skipped due to no PID activity from the scanning task (pid_inactive) drops dramatically. It is expected that this will increase the number of PTEs updated for NUMA hinting faults as well as hinting faults but these represent PTEs that would otherwise have been missed. The tradeoff is scan+fault overhead versus improving locality due to migration. On a 2-socket Cascade Lake test machine, the time to complete the workload is as follows; 6.6.0-rc2 6.6.0-rc2 sched-numabtrace-v1 sched-numabselective-v1 Min elsp-NUMA01_THREADLOCAL 174.22 ( 0.00%) 117.64 ( 32.48%) Amean elsp-NUMA01_THREADLOCAL 175.68 ( 0.00%) 123.34 * 29.79%* Stddev elsp-NUMA01_THREADLOCAL 1.20 ( 0.00%) 4.06 (-238.20%) CoeffVar elsp-NUMA01_THREADLOCAL 0.68 ( 0.00%) 3.29 (-381.70%) Max elsp-NUMA01_THREADLOCAL 177.18 ( 0.00%) 128.03 ( 27.74%) The time to complete the workload is reduced by almost 30%: 6.6.0-rc2 6.6.0-rc2 sched-numabtrace-v1 sched-numabselective-v1 / Duration User 91201.80 63506.64 Duration System 2015.53 1819.78 Duration Elapsed 1234.77 868.37 In this specific case, system CPU time was not increased but it's not universally true. From vmstat, the NUMA scanning and fault activity is as follows; 6.6.0-rc2 6.6.0-rc2 sched-numabtrace-v1 sched-numabselective-v1 Ops NUMA base-page range updates 64272.00 26374386.00 Ops NUMA PTE updates 36624.00 55538.00 Ops NUMA PMD updates 54.00 51404.00 Ops NUMA hint faults 15504.00 75786.00 Ops NUMA hint local faults % 14860.00 56763.00 Ops NUMA hint local percent 95.85 74.90 Ops NUMA pages migrated 1629.00 6469222.00 Both the number of PTE updates and hint faults is dramatically increased. While this is superficially unfortunate, it represents ranges that were simply skipped without the patch. As a result of the scanning and hinting faults, many more pages were also migrated but as the time to completion is reduced, the overhead is offset by the gain. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Raghavendra K T <raghavendra.kt@amd.com> Link: https://lore.kernel.org/r/20231010083143.19593-7-mgorman@techsingularity.net
2023-10-11sched/numa: Complete scanning of partial VMAs regardless of PID activityMel Gorman1-0/+1
NUMA Balancing skips VMAs when the current task has not trapped a NUMA fault within the VMA. If the VMA is skipped then mm->numa_scan_offset advances and a task that is trapping faults within the VMA may never fully update PTEs within the VMA. Force tasks to update PTEs for partially scanned PTEs. The VMA will be tagged for NUMA hints by some task but this removes some of the benefit of tracking PID activity within a VMA. A follow-on patch will mitigate this problem. The test cases and machines evaluated did not trigger the corner case so the performance results are neutral with only small changes within the noise from normal test-to-test variance. However, the next patch makes the corner case easier to trigger. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Raghavendra K T <raghavendra.kt@amd.com> Link: https://lore.kernel.org/r/20231010083143.19593-6-mgorman@techsingularity.net
2023-10-10sched/numa: Trace decisions related to skipping VMAsMel Gorman1-0/+8
NUMA balancing skips or scans VMAs for a variety of reasons. In preparation for completing scans of VMAs regardless of PID access, trace the reasons why a VMA was skipped. In a later patch, the tracing will be used to track if a VMA was forcibly scanned. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20231010083143.19593-4-mgorman@techsingularity.net
2023-09-21sched/headers: Standardize the <linux/sched/smt.h> header guard #endifIngo Molnar1-1/+1
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-09-21sched/headers: Standardize the <linux/sched/type.h> header guard #endifIngo Molnar1-1/+1
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-09-21sched/headers: Standardize the <linux/sched/vhost_task.h> header guard nameIngo Molnar1-4/+3
Use the same _LINUX_SCHED_ prefix nomenclature as the other 29 header guards in include/linux/sched/ do. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-09-21sched/headers: Add header guard to <linux/sched/deadline.h>Ingo Molnar1-0/+4
It's the only non-trivial header in include/linux/sched/ missing a header guard. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-09-20sched: Provide rt_mutex specific scheduler helpersPeter Zijlstra1-0/+4
With PREEMPT_RT there is a rt_mutex recursion problem where sched_submit_work() can use an rtlock (aka spinlock_t). More specifically what happens is: mutex_lock() /* really rt_mutex */ ... __rt_mutex_slowlock_locked() task_blocks_on_rt_mutex() // enqueue current task as waiter // do PI chain walk rt_mutex_slowlock_block() schedule() sched_submit_work() ... spin_lock() /* really rtlock */ ... __rt_mutex_slowlock_locked() task_blocks_on_rt_mutex() // enqueue current task as waiter *AGAIN* // *CONFUSION* Fix this by making rt_mutex do the sched_submit_work() early, before it enqueues itself as a waiter -- before it even knows *if* it will wait. [[ basically Thomas' patch but with different naming and a few asserts added ]] Originally-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230908162254.999499-5-bigeasy@linutronix.de
2023-09-15sched: Assert for_each_thread() is properly lockedMatthew Wilcox (Oracle)1-1/+2
list_for_each_entry_rcu() takes an optional fourth argument which allows RCU to assert that the correct lock is held. Several callers of for_each_thread() rely on their caller to be holding the appropriate lock, so this is a useful assertion to include. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Link: https://lore.kernel.org/r/20230821134428.2504912-1-willy@infradead.org
2023-09-11kernel: Drop IA64 support from sig_fault handlersArd Biesheuvel1-13/+4
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-08-30Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of ↵Linus Torvalds1-5/+2
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: - An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options") - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h") - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands") - vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions") - Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug") - Many singleton patches to various parts of the tree * tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...
2023-08-25document while_each_thread(), change first_tid() to use for_each_thread()Oleg Nesterov1-0/+4
Add the comment to explain that while_each_thread(g,t) is not rcu-safe unless g is stable (e.g. current). Even if g is a group leader and thus can't exit before t, t or another sub-thread can exec and remove g from the thread_group list. The only lockless user of while_each_thread() is first_tid() and it is fine in that it can't loop forever, yet for_each_thread() looks better and I am going to change while_each_thread/next_thread. Link: https://lkml.kernel.org/r/20230823170806.GA11724@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-21kill do_each_thread()Oleg Nesterov1-7/+0
Eric has pointed out that we still have 3 users of do_each_thread(). Change them to use for_each_process_thread() and kill this helper. There is a subtle change, after do_each_thread/while_each_thread g == t == &init_task, while after for_each_process_thread() they both point to nowhere, but this doesn't matter. > Why is for_each_process_thread() better than do_each_thread()? Say, for_each_process_thread() is rcu safe, do_each_thread() is not. And certainly for_each_process_thread(p, t) { do_something(p, t); } looks better than do_each_thread(p, t) { do_something(p, t); } while_each_thread(p, t); And again, there are only 3 users of this awkward helper left. It should have been killed years ago and in fact I thought it had already been killed. It uses while_each_thread() which needs some changes. Link: https://lkml.kernel.org/r/20230817163708.GA8248@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: "Christian Brauner (Microsoft)" <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jiri Slaby <jirislaby@kernel.org> # tty/serial Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-07-13sched: avoid false lockdep splat in put_task_struct()Wander Lairson Costa1-4/+14
In put_task_struct(), a spin_lock is indirectly acquired under the kernel stock. When running the kernel in real-time (RT) configuration, the operation is dispatched to a preemptible context call to ensure guaranteed preemption. However, if PROVE_RAW_LOCK_NESTING is enabled and __put_task_struct() is called while holding a raw_spinlock, lockdep incorrectly reports an "Invalid lock context" in the stock kernel. This false splat occurs because lockdep is unaware of the different route taken under RT. To address this issue, override the inner wait type to prevent the false lockdep splat. Suggested-by: Oleg Nesterov <oleg@redhat.com> Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Wander Lairson Costa <wander@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20230614122323.37957-3-wander@redhat.com
2023-07-13kernel/fork: beware of __put_task_struct() calling contextWander Lairson Costa1-1/+27
Under PREEMPT_RT, __put_task_struct() indirectly acquires sleeping locks. Therefore, it can't be called from an non-preemptible context. One practical example is splat inside inactive_task_timer(), which is called in a interrupt context: CPU: 1 PID: 2848 Comm: life Kdump: loaded Tainted: G W --------- Hardware name: HP ProLiant DL388p Gen8, BIOS P70 07/15/2012 Call Trace: dump_stack_lvl+0x57/0x7d mark_lock_irq.cold+0x33/0xba mark_lock+0x1e7/0x400 mark_usage+0x11d/0x140 __lock_acquire+0x30d/0x930 lock_acquire.part.0+0x9c/0x210 rt_spin_lock+0x27/0xe0 refill_obj_stock+0x3d/0x3a0 kmem_cache_free+0x357/0x560 inactive_task_timer+0x1ad/0x340 __run_hrtimer+0x8a/0x1a0 __hrtimer_run_queues+0x91/0x130 hrtimer_interrupt+0x10f/0x220 __sysvec_apic_timer_interrupt+0x7b/0xd0 sysvec_apic_timer_interrupt+0x4f/0xd0 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0033:0x7fff196bf6f5 Instead of calling __put_task_struct() directly, we defer it using call_rcu(). A more natural approach would use a workqueue, but since in PREEMPT_RT, we can't allocate dynamic memory from atomic context, the code would become more complex because we would need to put the work_struct instance in the task_struct and initialize it when we allocate a new task_struct. The issue is reproducible with stress-ng: while true; do stress-ng --sched deadline --sched-period 1000000000 \ --sched-runtime 800000000 --sched-deadline \ 1000000000 --mmapfork 23 -t 20 done Reported-by: Hu Chunyu <chuhu@redhat.com> Suggested-by: Oleg Nesterov <oleg@redhat.com> Suggested-by: Valentin Schneider <vschneid@redhat.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Wander Lairson Costa <wander@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20230614122323.37957-2-wander@redhat.com
2023-07-04Merge tag 'core_guards_for_6.5_rc1' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue Pull scope-based resource management infrastructure from Peter Zijlstra: "These are the first few patches in the Scope-based Resource Management series that introduce the infrastructure but not any conversions as of yet. Adding the infrastructure now allows multiple people to start using them. Of note is that Sparse will need some work since it doesn't yet understand this attribute and might have decl-after-stmt issues" * tag 'core_guards_for_6.5_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue: kbuild: Drop -Wdeclaration-after-statement locking: Introduce __cleanup() based infrastructure apparmor: Free up __cleanup() name dmaengine: ioat: Free up __cleanup() name
2023-06-28Merge tag 'sched-core-2023-06-27' of ↵Linus Torvalds3-6/+18
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "Scheduler SMP load-balancer improvements: - Avoid unnecessary migrations within SMT domains on hybrid systems. Problem: On hybrid CPU systems, (processors with a mixture of higher-frequency SMT cores and lower-frequency non-SMT cores), under the old code lower-priority CPUs pulled tasks from the higher-priority cores if more than one SMT sibling was busy - resulting in many unnecessary task migrations. Solution: The new code improves the load balancer to recognize SMT cores with more than one busy sibling and allows lower-priority CPUs to pull tasks, which avoids superfluous migrations and lets lower-priority cores inspect all SMT siblings for the busiest queue. - Implement the 'runnable boosting' feature in the EAS balancer: consider CPU contention in frequency, EAS max util & load-balance busiest CPU selection. This improves CPU utilization for certain workloads, while leaves other key workloads unchanged. Scheduler infrastructure improvements: - Rewrite the scheduler topology setup code by consolidating it into the build_sched_topology() helper function and building it dynamically on the fly. - Resolve the local_clock() vs. noinstr complications by rewriting the code: provide separate sched_clock_noinstr() and local_clock_noinstr() functions to be used in instrumentation code, and make sure it is all instrumentation-safe. Fixes: - Fix a kthread_park() race with wait_woken() - Fix misc wait_task_inactive() bugs unearthed by the -rt merge: - Fix UP PREEMPT bug by unifying the SMP and UP implementations - Fix task_struct::saved_state handling - Fix various rq clock update bugs, unearthed by turning on the rq clock debugging code. - Fix the PSI WINDOW_MIN_US trigger limit, which was easy to trigger by creating enough cgroups, by removing the warnign and restricting window size triggers to PSI file write-permission or CAP_SYS_RESOURCE. - Propagate SMT flags in the topology when removing degenerate domain - Fix grub_reclaim() calculation bug in the deadline scheduler code - Avoid resetting the min update period when it is unnecessary, in psi_trigger_destroy(). - Don't balance a task to its current running CPU in load_balance(), which was possible on certain NUMA topologies with overlapping groups. - Fix the sched-debug printing of rq->nr_uninterruptible Cleanups: - Address various -Wmissing-prototype warnings, as a preparation to (maybe) enable this warning in the future. - Remove unused code - Mark more functions __init - Fix shadow-variable warnings" * tag 'sched-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits) sched/core: Avoid multiple calling update_rq_clock() in __cfsb_csd_unthrottle() sched/core: Avoid double calling update_rq_clock() in __balance_push_cpu_stop() sched/core: Fixed missing rq clock update before calling set_rq_offline() sched/deadline: Update GRUB description in the documentation sched/deadline: Fix bandwidth reclaim equation in GRUB sched/wait: Fix a kthread_park race with wait_woken() sched/topology: Mark set_sched_topology() __init sched/fair: Rename variable cpu_util eff_util arm64/arch_timer: Fix MMIO byteswap sched/fair, cpufreq: Introduce 'runnable boosting' sched/fair: Refactor CPU utilization functions cpuidle: Use local_clock_noinstr() sched/clock: Provide local_clock_noinstr() x86/tsc: Provide sched_clock_noinstr() clocksource: hyper-v: Provide noinstr sched_clock() clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid special casing U64_MAX x86/vdso: Fix gettimeofday masking math64: Always inline u128 version of mul_u64_u64_shr() s390/time: Provide sched_clock_noinstr() loongarch: Provide noinstr sched_clock_read() ...
2023-06-27Merge tag 'timers-core-2023-06-26' of ↵Linus Torvalds1-1/+1
ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "Time, timekeeping and related device driver updates: Core: - A set of fixes, cleanups and enhancements to the posix timer code: - Prevent another possible live lock scenario in the exit() path, which affects POSIX_CPU_TIMERS_TASK_WORK enabled architectures. - Fix a loop termination issue which was reported syzcaller/KSAN in the posix timer ID allocation code. That triggered a deeper look into the posix-timer code which unearthed more small issues. - Add missing READ/WRITE_ONCE() annotations - Fix or remove completely outdated comments - Document places which are subtle and completely undocumented. - Add missing hrtimer modes to the trace event decoder - Small cleanups and enhancements all over the place Drivers: - Rework the Hyper-V clocksource and sched clock setup code - Remove a deprecated clocksource driver - Small fixes and enhancements all over the place" * tag 'timers-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits) clocksource/drivers/cadence-ttc: Fix memory leak in ttc_timer_probe dt-bindings: timers: Add Ralink SoCs timer clocksource/drivers/hyper-v: Rework clocksource and sched clock setup dt-bindings: timer: brcm,kona-timer: convert to YAML clocksource/drivers/imx-gpt: Fold <soc/imx/timer.h> into its only user clk: imx: Drop inclusion of unused header <soc/imx/timer.h> hrtimer: Add missing sparse annotations to hrtimer locking clocksource/drivers/imx-gpt: Use only a single name for functions clocksource/drivers/loongson1: Move PWM timer to clocksource framework dt-bindings: timer: Add Loongson-1 clocksource MIPS: Loongson32: Remove deprecated PWM timer clocksource clocksource/drivers/ingenic-timer: Use pm_sleep_ptr() macro tracing/timer: Add missing hrtimer modes to decode_hrtimer_mode(). posix-timers: Add sys_ni_posix_timers() prototype tick/rcu: Fix bogus ratelimit condition alarmtimer: Remove unnecessary (void *) cast alarmtimer: Remove unnecessary initialization of variable 'ret' posix-timers: Refer properly to CONFIG_HIGH_RES_TIMERS posix-timers: Polish coding style in a few places posix-timers: Remove pointless comments ...
2023-06-26locking: Introduce __cleanup() based infrastructurePeter Zijlstra1-0/+2
Use __attribute__((__cleanup__(func))) to build: - simple auto-release pointers using __free() - 'classes' with constructor and destructor semantics for scope-based resource management. - lock guards based on the above classes. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230612093537.614161713%40infradead.org
2023-06-18posix-timers: Ensure timer ID search-loop limit is validThomas Gleixner1-1/+1
posix_timer_add() tries to allocate a posix timer ID by starting from the cached ID which was stored by the last successful allocation. This is done in a loop searching the ID space for a free slot one by one. The loop has to terminate when the search wrapped around to the starting point. But that's racy vs. establishing the starting point. That is read out lockless, which leads to the following problem: CPU0 CPU1 posix_timer_add() start = sig->posix_timer_id; lock(hash_lock); ... posix_timer_add() if (++sig->posix_timer_id < 0) start = sig->posix_timer_id; sig->posix_timer_id = 0; So CPU1 can observe a negative start value, i.e. -1, and the loop break never happens because the condition can never be true: if (sig->posix_timer_id == start) break; While this is unlikely to ever turn into an endless loop as the ID space is huge (INT_MAX), the racy read of the start value caught the attention of KCSAN and Dmitry unearthed that incorrectness. Rewrite it so that all id operations are under the hash lock. Reported-by: syzbot+5c54bd3eb218bb595aa9@syzkaller.appspotmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/87bkhzdn6g.ffs@tglx
2023-06-16sched/topology: Mark set_sched_topology() __initMiaohe Lin1-1/+1
All callers of set_sched_topology() are within __init section. Mark it __init too. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <vschneid@redhat.com> Link: https://lore.kernel.org/r/20230603073645.1173332-1-linmiaohe@huawei.com
2023-06-05sched/clock: Provide local_clock_noinstr()Peter Zijlstra1-1/+16
Now that all ARCH_WANTS_NO_INSTR architectures (arm64, loongarch, s390, x86) provide sched_clock_noinstr(), use this to provide local_clock_noinstr(). This local_clock_noinstr() will be safe to use from noinstr code with the assumption that any such noinstr code is non-preemptible (it had better be, entry code will have IRQs disabled while __cpuidle must have preemption disabled). Specifically, preempt_enable_notrace(), a common part of many a sched_clock() implementation calls out to schedule() -- even though, per the above, it will never trigger -- which frustrates noinstr validation. vmlinux.o: warning: objtool: local_clock+0xb5: call to preempt_schedule_notrace_thunk() leaves .noinstr.text section Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Michael Kelley <mikelley@microsoft.com> # Hyper-V Link: https://lore.kernel.org/r/20230519102715.978624636@infradead.org
2023-06-02fork, vhost: Use CLONE_THREAD to fix freezer/ps regressionMike Christie2-13/+3
When switching from kthreads to vhost_tasks two bugs were added: 1. The vhost worker tasks's now show up as processes so scripts doing ps or ps a would not incorrectly detect the vhost task as another process. 2. kthreads disabled freeze by setting PF_NOFREEZE, but vhost tasks's didn't disable or add support for them. To fix both bugs, this switches the vhost task to be thread in the process that does the VHOST_SET_OWNER ioctl, and has vhost_worker call get_signal to support SIGKILL/SIGSTOP and freeze signals. Note that SIGKILL/STOP support is required because CLONE_THREAD requires CLONE_SIGHAND which requires those 2 signals to be supported. This is a modified version of the patch written by Mike Christie <michael.christie@oracle.com> which was a modified version of patch originally written by Linus. Much of what depended upon PF_IO_WORKER now depends on PF_USER_WORKER. Including ignoring signals, setting up the register state, and having get_signal return instead of calling do_group_exit. Tidied up the vhost_task abstraction so that the definition of vhost_task only needs to be visible inside of vhost_task.c. Making it easier to review the code and tell what needs to be done where. As part of this the main loop has been moved from vhost_worker into vhost_task_fn. vhost_worker now returns true if work was done. The main loop has been updated to call get_signal which handles SIGSTOP, freezing, and collects the message that tells the thread to exit as part of process exit. This collection clears __fatal_signal_pending. This collection is not guaranteed to clear signal_pending() so clear that explicitly so the schedule() sleeps. For now the vhost thread continues to exist and run work until the last file descriptor is closed and the release function is called as part of freeing struct file. To avoid hangs in the coredump rendezvous and when killing threads in a multi-threaded exec. The coredump code and de_thread have been modified to ignore vhost threads. Remvoing the special case for exec appears to require teaching vhost_dev_flush how to directly complete transactions in case the vhost thread is no longer running. Removing the special case for coredump rendezvous requires either the above fix needed for exec or moving the coredump rendezvous into get_signal. Fixes: 6e890c5d5021 ("vhost: use vhost_tasks for worker threads") Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Co-developed-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-05-08sched/topology: Remove SHARED_CHILD from ASYM_PACKINGRicardo Neri1-4/+1
Only x86 and Power7 use ASYM_PACKING. They use it differently. Power7 has cores of equal priority, but the SMT siblings of a core have different priorities. Parent scheduling domains do not need (nor have) the ASYM_PACKING flag. SHARED_CHILD is not needed. Using SHARED_PARENT would cause the topology debug code to complain. X86 has cores of different priority, but all the SMT siblings of the core have equal priority. It needs ASYM_PACKING at the MC level, but not at the SMT level (it also needs it at upper levels if they have scheduling groups of different priority). Removing ASYM_PACKING from the SMT domain causes the topology debug code to complain. Remove SHARED_CHILD for now. We still need a topology check that satisfies both architectures. Suggested-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20230406203148.19182-10-ricardo.neri-calderon@linux.intel.com
2023-04-30Merge tag 'iommu-updates-v6.4' of ↵Linus Torvalds1-32/+0
git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu Pull iommu updates from Joerg Roedel: - Convert to platform remove callback returning void - Extend changing default domain to normal group - Intel VT-d updates: - Remove VT-d virtual command interface and IOASID - Allow the VT-d driver to support non-PRI IOPF - Remove PASID supervisor request support - Various small and misc cleanups - ARM SMMU updates: - Device-tree binding updates: * Allow Qualcomm GPU SMMUs to accept relevant clock properties * Document Qualcomm 8550 SoC as implementing an MMU-500 * Favour new "qcom,smmu-500" binding for Adreno SMMUs - Fix S2CR quirk detection on non-architectural Qualcomm SMMU implementations - Acknowledge SMMUv3 PRI queue overflow when consuming events - Document (in a comment) why ATS is disabled for bypass streams - AMD IOMMU updates: - 5-level page-table support - NUMA awareness for memory allocations - Unisoc driver: Support for reattaching an existing domain - Rockchip driver: Add missing set_platform_dma_ops callback - Mediatek driver: Adjust the dma-ranges - Various other small fixes and cleanups * tag 'iommu-updates-v6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (82 commits) iommu: Remove iommu_group_get_by_id() iommu: Make iommu_release_device() static iommu/vt-d: Remove BUG_ON in dmar_insert_dev_scope() iommu/vt-d: Remove a useless BUG_ON(dev->is_virtfn) iommu/vt-d: Remove BUG_ON in map/unmap() iommu/vt-d: Remove BUG_ON when domain->pgd is NULL iommu/vt-d: Remove BUG_ON in handling iotlb cache invalidation iommu/vt-d: Remove BUG_ON on checking valid pfn range iommu/vt-d: Make size of operands same in bitwise operations iommu/vt-d: Remove PASID supervisor request support iommu/vt-d: Use non-privileged mode for all PASIDs iommu/vt-d: Remove extern from function prototypes iommu/vt-d: Do not use GFP_ATOMIC when not needed iommu/vt-d: Remove unnecessary checks in iopf disabling path iommu/vt-d: Move PRI handling to IOPF feature path iommu/vt-d: Move pfsid and ats_qdep calculation to device probe path iommu/vt-d: Move iopf code from SVA to IOPF enabling path iommu/vt-d: Allow SVA with device-specific IOPF dmaengine: idxd: Add enable/disable device IOPF feature arm64: dts: mt8186: Add dma-ranges for the parent "soc" node ...
2023-04-29Merge tag 'sched-core-2023-04-27' of ↵Linus Torvalds1-0/+5
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: - Allow unprivileged PSI poll()ing - Fix performance regression introduced by mm_cid - Improve livepatch stalls by adding livepatch task switching to cond_resched(). This resolves livepatching busy-loop stalls with certain CPU-bound kthreads - Improve sched_move_task() performance on autogroup configs - On core-scheduling CPUs, avoid selecting throttled tasks to run - Misc cleanups, fixes and improvements * tag 'sched-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/clock: Fix local_clock() before sched_clock_init() sched/rt: Fix bad task migration for rt tasks sched: Fix performance regression introduced by mm_cid sched/core: Make sched_dynamic_mutex static sched/psi: Allow unprivileged polling of N*2s period sched/psi: Extract update_triggers side effect sched/psi: Rename existing poll members in preparation sched/psi: Rearrange polling code in preparation sched/fair: Fix inaccurate tally of ttwu_move_affine vhost: Fix livepatch timeouts in vhost_worker() livepatch,sched: Add livepatch task switching to cond_resched() livepatch: Skip task_call_func() for current task livepatch: Convert stack entries array to percpu sched: Interleave cfs bandwidth timers for improved single thread performance at low utilization sched/core: Reduce cost of sched_move_task when config autogroup sched/core: Avoid selecting the task that is throttled to run when core-sched enable sched/topology: Make sched_energy_mutex,update static
2023-04-29Merge tag 'objtool-core-2023-04-27' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - Mark arch_cpu_idle_dead() __noreturn, make all architectures & drivers that did this inconsistently follow this new, common convention, and fix all the fallout that objtool can now detect statically - Fix/improve the ORC unwinder becoming unreliable due to UNWIND_HINT_EMPTY ambiguity, split it into UNWIND_HINT_END_OF_STACK and UNWIND_HINT_UNDEFINED to resolve it - Fix noinstr violations in the KCSAN code and the lkdtm/stackleak code - Generate ORC data for __pfx code - Add more __noreturn annotations to various kernel startup/shutdown and panic functions - Misc improvements & fixes * tag 'objtool-core-2023-04-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) x86/hyperv: Mark hv_ghcb_terminate() as noreturn scsi: message: fusion: Mark mpt_halt_firmware() __noreturn x86/cpu: Mark {hlt,resume}_play_dead() __noreturn btrfs: Mark btrfs_assertfail() __noreturn objtool: Include weak functions in global_noreturns check cpu: Mark nmi_panic_self_stop() __noreturn cpu: Mark panic_smp_self_stop() __noreturn arm64/cpu: Mark cpu_park_loop() and friends __noreturn x86/head: Mark *_start_kernel() __noreturn init: Mark start_kernel() __noreturn init: Mark [arch_call_]rest_init() __noreturn objtool: Generate ORC data for __pfx code x86/linkage: Fix padding for typed functions objtool: Separate prefix code from stack validation code objtool: Remove superfluous dead_end_function() check objtool: Add symbol iteration helpers objtool: Add WARN_INSN() scripts/objdump-func: Support multiple functions context_tracking: Fix KCSAN noinstr violation objtool: Add stackleak instrumentation to uaccess safe list ...
2023-04-28Merge tag 'x86_mm_for_6.4' of ↵Linus Torvalds1-1/+7
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 LAM (Linear Address Masking) support from Dave Hansen: "Add support for the new Linear Address Masking CPU feature. This is similar to ARM's Top Byte Ignore and allows userspace to store metadata in some bits of pointers without masking it out before use" * tag 'x86_mm_for_6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm/iommu/sva: Do not allow to set FORCE_TAGGED_SVA bit from outside x86/mm/iommu/sva: Fix error code for LAM enabling failure due to SVA selftests/x86/lam: Add test cases for LAM vs thread creation selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA test cases for linear-address masking selftests/x86/lam: Add inherit test cases for linear-address masking selftests/x86/lam: Add io_uring test cases for linear-address masking selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address masking selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking x86/mm/iommu/sva: Make LAM and SVA mutually exclusive iommu/sva: Replace pasid_valid() helper with mm_valid_pasid() mm: Expose untagging mask in /proc/$PID/status x86/mm: Provide arch_prctl() interface for LAM x86/mm: Reduce untagged_addr() overhead for systems without LAM x86/uaccess: Provide untagged_addr() and remove tags before address check mm: Introduce untagged_addr_remote() x86/mm: Handle LAM on context switch x86: CPUID and CR3/CR4 flags for Linear Address Masking x86: Allow atomic MM_CONTEXT flags setting x86/mm: Rework address range check in get_user() and put_user()
2023-04-28Merge tag 'mm-stable-2023-04-27-15-30' of ↵Linus Torvalds3-0/+41
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of switching from a user process to a kernel thread. - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav. - zsmalloc performance improvements from Sergey Senozhatsky. - Yue Zhao has found and fixed some data race issues around the alteration of memcg userspace tunables. - VFS rationalizations from Christoph Hellwig: - removal of most of the callers of write_one_page() - make __filemap_get_folio()'s return value more useful - Luis Chamberlain has changed tmpfs so it no longer requires swap backing. Use `mount -o noswap'. - Qi Zheng has made the slab shrinkers operate locklessly, providing some scalability benefits. - Keith Busch has improved dmapool's performance, making part of its operations O(1) rather than O(n). - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd, permitting userspace to wr-protect anon memory unpopulated ptes. - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather than exclusive, and has fixed a bunch of errors which were caused by its unintuitive meaning. - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature, which causes minor faults to install a write-protected pte. - Vlastimil Babka has done some maintenance work on vma_merge(): cleanups to the kernel code and improvements to our userspace test harness. - Cleanups to do_fault_around() by Lorenzo Stoakes. - Mike Rapoport has moved a lot of initialization code out of various mm/ files and into mm/mm_init.c. - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for DRM, but DRM doesn't use it any more. - Lorenzo has also coverted read_kcore() and vread() to use iterators and has thereby removed the use of bounce buffers in some cases. - Lorenzo has also contributed further cleanups of vma_merge(). - Chaitanya Prakash provides some fixes to the mmap selftesting code. - Matthew Wilcox changes xfs and afs so they no longer take sleeping locks in ->map_page(), a step towards RCUification of pagefaults. - Suren Baghdasaryan has improved mmap_lock scalability by switching to per-VMA locking. - Frederic Weisbecker has reworked the percpu cache draining so that it no longer causes latency glitches on cpu isolated workloads. - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig logic. - Liu Shixin has changed zswap's initialization so we no longer waste a chunk of memory if zswap is not being used. - Yosry Ahmed has improved the performance of memcg statistics flushing. - David Stevens has fixed several issues involving khugepaged, userfaultfd and shmem. - Christoph Hellwig has provided some cleanup work to zram's IO-related code paths. - David Hildenbrand has fixed up some issues in the selftest code's testing of our pte state changing. - Pankaj Raghav has made page_endio() unneeded and has removed it. - Peter Xu contributed some rationalizations of the userfaultfd selftests. - Yosry Ahmed has fixed an issue around memcg's page recalim accounting. - Chaitanya Prakash has fixed some arm-related issues in the selftests/mm code. - Longlong Xia has improved the way in which KSM handles hwpoisoned pages. - Peter Xu fixes a few issues with uffd-wp at fork() time. - Stefan Roesch has changed KSM so that it may now be used on a per-process and per-cgroup basis. * tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm,unmap: avoid flushing TLB in batch if PTE is inaccessible shmem: restrict noswap option to initial user namespace mm/khugepaged: fix conflicting mods to collapse_file() sparse: remove unnecessary 0 values from rc mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area() hugetlb: pte_alloc_huge() to replace huge pte_alloc_map() maple_tree: fix allocation in mas_sparse_area() mm: do not increment pgfault stats when page fault handler retries zsmalloc: allow only one active pool compaction context selftests/mm: add new selftests for KSM mm: add new KSM process and sysfs knobs mm: add new api to enable ksm per process mm: shrinkers: fix debugfs file permissions mm: don't check VMA write permissions if the PTE/PMD indicates write permissions migrate_pages_batch: fix statistics for longterm pin retry userfaultfd: use helper function range_in_vma() lib/show_mem.c: use for_each_populated_zone() simplify code mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list() fs/buffer: convert create_page_buffers to folio_create_buffers fs/buffer: add folio_create_empty_buffers helper ...
2023-04-22mm: add new api to enable ksm per processStefan Roesch1-0/+1
Patch series "mm: process/cgroup ksm support", v9. So far KSM can only be enabled by calling madvise for memory regions. To be able to use KSM for more workloads, KSM needs to have the ability to be enabled / disabled at the process / cgroup level. Use case 1: The madvise call is not available in the programming language. An example for this are programs with forked workloads using a garbage collected language without pointers. In such a language madvise cannot be made available. In addition the addresses of objects get moved around as they are garbage collected. KSM sharing needs to be enabled "from the outside" for these type of workloads. Use case 2: The same interpreter can also be used for workloads where KSM brings no benefit or even has overhead. We'd like to be able to enable KSM on a workload by workload basis. Use case 3: With the madvise call sharing opportunities are only enabled for the current process: it is a workload-local decision. A considerable number of sharing opportunities may exist across multiple workloads or jobs (if they are part of the same security domain). Only a higler level entity like a job scheduler or container can know for certain if its running one or more instances of a job. That job scheduler however doesn't have the necessary internal workload knowledge to make targeted madvise calls. Security concerns: In previous discussions security concerns have been brought up. The problem is that an individual workload does not have the knowledge about what else is running on a machine. Therefore it has to be very conservative in what memory areas can be shared or not. However, if the system is dedicated to running multiple jobs within the same security domain, its the job scheduler that has the knowledge that sharing can be safely enabled and is even desirable. Performance: Experiments with using UKSM have shown a capacity increase of around 20%. Here are the metrics from an instagram workload (taken from a machine with 64GB main memory): full_scans: 445 general_profit: 20158298048 max_page_sharing: 256 merge_across_nodes: 1 pages_shared: 129547 pages_sharing: 5119146 pages_to_scan: 4000 pages_unshared: 1760924 pages_volatile: 10761341 run: 1 sleep_millisecs: 20 stable_node_chains: 167 stable_node_chains_prune_millisecs: 2000 stable_node_dups: 2751 use_zero_pages: 0 zero_pages_sharing: 0 After the service is running for 30 minutes to an hour, 4 to 5 million shared pages are common for this workload when using KSM. Detailed changes: 1. New options for prctl system command This patch series adds two new options to the prctl system call. The first one allows to enable KSM at the process level and the second one to query the setting. The setting will be inherited by child processes. With the above setting, KSM can be enabled for the seed process of a cgroup and all processes in the cgroup will inherit the setting. 2. Changes to KSM processing When KSM is enabled at the process level, the KSM code will iterate over all the VMA's and enable KSM for the eligible VMA's. When forking a process that has KSM enabled, the setting will be inherited by the new child process. 3. Add general_profit metric The general_profit metric of KSM is specified in the documentation, but not calculated. This adds the general profit metric to /sys/kernel/debug/mm/ksm. 4. Add more metrics to ksm_stat This adds the process profit metric to /proc/<pid>/ksm_stat. 5. Add more tests to ksm_tests and ksm_functional_tests This adds an option to specify the merge type to the ksm_tests. This allows to test madvise and prctl KSM. It also adds a two new tests to ksm_functional_tests: one to test the new prctl options and the other one is a fork test to verify that the KSM process setting is inherited by client processes. This patch (of 3): So far KSM can only be enabled by calling madvise for memory regions. To be able to use KSM for more workloads, KSM needs to have the ability to be enabled / disabled at the process / cgroup level. 1. New options for prctl system command This patch series adds two new options to the prctl system call. The first one allows to enable KSM at the process level and the second one to query the setting. The setting will be inherited by child processes. With the above setting, KSM can be enabled for the seed process of a cgroup and all processes in the cgroup will inherit the setting. 2. Changes to KSM processing When KSM is enabled at the process level, the KSM code will iterate over all the VMA's and enable KSM for the eligible VMA's. When forking a process that has KSM enabled, the setting will be inherited by the new child process. 1) Introduce new MMF_VM_MERGE_ANY flag This introduces the new flag MMF_VM_MERGE_ANY flag. When this flag is set, kernel samepage merging (ksm) gets enabled for all vma's of a process. 2) Setting VM_MERGEABLE on VMA creation When a VMA is created, if the MMF_VM_MERGE_ANY flag is set, the VM_MERGEABLE flag will be set for this VMA. 3) support disabling of ksm for a process This adds the ability to disable ksm for a process if ksm has been enabled for the process with prctl. 4) add new prctl option to get and set ksm for a process This adds two new options to the prctl system call - enable ksm for all vmas of a process (if the vmas support it). - query if ksm has been enabled for a process. 3. Disabling MMF_VM_MERGE_ANY for storage keys in s390 In the s390 architecture when storage keys are used, the MMF_VM_MERGE_ANY will be disabled. Link: https://lkml.kernel.org/r/20230418051342.1919757-1-shr@devkernel.io Link: https://lkml.kernel.org/r/20230418051342.1919757-2-shr@devkernel.io Signed-off-by: Stefan Roesch <shr@devkernel.io> Acked-by: David Hildenbrand <david@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-21sched: Fix performance regression introduced by mm_cidMathieu Desnoyers1-0/+5
Introduce per-mm/cpu current concurrency id (mm_cid) to fix a PostgreSQL sysbench regression reported by Aaron Lu. Keep track of the currently allocated mm_cid for each mm/cpu rather than freeing them immediately on context switch. This eliminates most atomic operations when context switching back and forth between threads belonging to different memory spaces in multi-threaded scenarios (many processes, each with many threads). The per-mm/per-cpu mm_cid values are serialized by their respective runqueue locks. Thread migration is handled by introducing invocation to sched_mm_cid_migrate_to() (with destination runqueue lock held) in activate_task() for migrating tasks. If the destination cpu's mm_cid is unset, and if the source runqueue is not actively using its mm_cid, then the source cpu's mm_cid is moved to the destination cpu on migration. Introduce a task-work executed periodically, similarly to NUMA work, which delays reclaim of cid values when they are unused for a period of time. Keep track of the allocation time for each per-cpu cid, and let the task work clear them when they are observed to be older than SCHED_MM_CID_PERIOD_NS and unused. This task work also clears all mm_cids which are greater or equal to the Hamming weight of the mm cidmask to keep concurrency ids compact. Because we want to ensure the mm_cid converges towards the smaller values as migrations happen, the prior optimization that was done when context switching between threads belonging to the same mm is removed, because it could delay the lazy release of the destination runqueue mm_cid after it has been replaced by a migration. Removing this prior optimization is not an issue performance-wise because the introduced per-mm/per-cpu mm_cid tracking also covers this more specific case. Fixes: af7f588d8f73 ("sched: Introduce per-memory-map concurrency ID") Reported-by: Aaron Lu <aaron.lu@intel.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Aaron Lu <aaron.lu@intel.com> Link: https://lore.kernel.org/lkml/20230327080502.GA570847@ziqianlu-desk2/
2023-04-19sched/isolation: add cpu_is_isolated() APIFrederic Weisbecker1-0/+12
Patch series "memcg, cpuisol: do not interfere pcp cache charges draining with cpuisol workloads". Leonardo has reported [1] that pcp memcg charge draining can interfere with cpu isolated workloads. The said draining is done from a WQ context with a pcp worker scheduled on each CPU which holds any cached charges for a specific memcg hierarchy. Operation is not really a common operation [2]. It can be triggered from the userspace though so some care is definitely due. Leonardo has tried to address the issue by allowing remote charge draining [3]. This approach requires an additional locking to synchronize pcp caches sync from a remote cpu from local pcp consumers. Even though the proposed lock was per-cpu there is still potential for contention and less predictable behavior. This patchset addresses the issue from a different angle. Rather than dealing with a potential synchronization, cpus which are isolated are simply never scheduled to be drained. This means that a small amount of charges could be laying around and waiting for a later use or they are flushed when a different memcg is charged from the same cpu. More details are in patch 2. The first patch from Frederic is implementing an abstraction to tell whether a specific cpu has been isolated and therefore require a special treatment. This patch (of 2): Provide this new API to check if a CPU has been isolated either through isolcpus= or nohz_full= kernel parameter. It aims at avoiding kernel load deemed to be safely spared on CPUs running sensitive workload that can't bear any disturbance, such as pcp cache draining. Link: https://lkml.kernel.org/r/20230317134448.11082-1-mhocko@kernel.org Link: https://lkml.kernel.org/r/20230317134448.11082-2-mhocko@kernel.org Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Leonardo Bras <leobras@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-04-14sched: Fix KCSAN noinstr violationJosh Poimboeuf1-1/+1
With KCSAN enabled, end_of_stack() can get out-of-lined. Force it inline. Fixes the following warnings: vmlinux.o: warning: objtool: check_stackleak_irqoff+0x2b: call to end_of_stack() leaves .noinstr.text section Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/cc1b4d73d3a428a00d206242a68fdf99a934ca7b.1681320026.git.jpoimboe@kernel.org
2023-03-31iommu/sva: Move PASID helpers to sva codeJacob Pan1-26/+0
Preparing to remove IOASID infrastructure, PASID management will be under SVA code. Decouple mm code from IOASID. Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> Reviewed-by: Kevin Tian <kevin.tian@intel.com> Link: https://lore.kernel.org/r/20230322200803.869130-3-jacob.jun.pan@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
2023-03-29lazy tlb: allow lazy tlb mm refcounting to be configurableNicholas Piggin1-3/+15
Add CONFIG_MMU_TLB_REFCOUNT which enables refcounting of the lazy tlb mm when it is context switched. This can be disabled by architectures that don't require this refcounting if they clean up lazy tlb mms when the last refcount is dropped. Currently this is always enabled, so the patch introduces no functional change. Link: https://lkml.kernel.org/r/20230203071837.1136453-4-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-29lazy tlb: introduce lazy tlb mm refcount helper functionsNicholas Piggin1-0/+16
Add explicit _lazy_tlb annotated functions for lazy tlb mm refcounting. This makes the lazy tlb mm references more obvious, and allows the refcounting scheme to be modified in later changes. There is no functional change with this patch. Link: https://lkml.kernel.org/r/20230203071837.1136453-3-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-23vhost_task: Allow vhost layer to use copy_processMike Christie1-0/+23
Qemu will create vhost devices in the kernel which perform network, SCSI, etc IO and management operations from worker threads created by the kthread API. Because the kthread API does a copy_process on the kthreadd thread, the vhost layer has to use kthread_use_mm to access the Qemu thread's memory and cgroup_attach_task_all to add itself to the Qemu thread's cgroups, and it bypasses the RLIMIT_NPROC limit which can result in VMs creating more threads than the admin expected. This patch adds a new struct vhost_task which can be used instead of kthreads. They allow the vhost layer to use copy_process and inherit the userspace process's mm and cgroups, the task is accounted for under the userspace's nproc count and can be seen in its process tree, and other features like namespaces work and are inherited by default. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2023-03-16iommu/sva: Replace pasid_valid() helper with mm_valid_pasid()Kirill A. Shutemov1-1/+7
Kernel has few users of pasid_valid() and all but one checks if the process has PASID allocated. The helper takes ioasid_t as the input. Replace the helper with mm_valid_pasid() that takes mm_struct as the argument. The only call that checks PASID that is not tied to mm_struct is open-codded now. This is preparatory patch. It helps avoid ifdeffery: no need to dereference mm->pasid in generic code to check if the process has PASID. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/all/20230312112612.31869-11-kirill.shutemov%40linux.intel.com
2023-03-12fork: allow kernel code to call copy_processMike Christie1-0/+2
The next patch adds helpers like create_io_thread, but for use by the vhost layer. There are several functions, so they are in their own file instead of cluttering up fork.c. This patch allows that new file to call copy_process. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-03-12fork: Add kernel_clone_args flag to ignore signalsMike Christie1-0/+1
Since: commit 10ab825bdef8 ("change kernel threads to ignore signals instead of blocking them") kthreads have been ignoring signals by default, and the vhost layer has never had a need to change that. This patch adds an option flag, USER_WORKER_SIG_IGN, handled in copy_process() after copy_sighand() and copy_signals() so vhost_tasks added in the next patches can continue to ignore singals. Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-03-12fork: add kernel_clone_args flag to not dup/clone filesMike Christie1-0/+1
Each vhost device gets a thread that is used to perform IO and management operations. Instead of a thread that is accessing a device, the thread is part of the device, so when it creates a thread using a helper based on copy_process we can't dup or clone the parent's files/FDS because it would do an extra increment on ourself. Later, when we do: Qemu process exits: do_exit -> exit_files -> put_files_struct -> close_files we would leak the device's resources because of that extra refcount on the fd or file_struct. This patch adds a no_files option so these worker threads can prevent taking an extra refcount on themselves. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-03-12fork/vm: Move common PF_IO_WORKER behavior to new flagMike Christie1-0/+1
This adds a new flag, PF_USER_WORKER, that's used for behavior common to to both PF_IO_WORKER and users like vhost which will use a new helper instead of create_io_thread because they require different behavior for operations like signal handling. The common behavior PF_USER_WORKER covers is the vm reclaim handling. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-03-12kernel: Make io_thread and kthread bit fieldsMike Christie1-2/+2
We only set args->io_thread/kthread to 0 or 1 then test if they are set, so make them bit fields. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-03-12kernel: Allow a kernel thread's name to be set in copy_processMike Christie1-1/+3
This patch allows kernel users to pass in the thread name so it can be set during creation instead of having to use set_task_comm after the thread is created. Signed-off-by: Mike Christie <michael.christie@oracle.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-02-24Merge tag 'mm-stable-2023-02-20-13-37' of ↵Linus Torvalds1-1/+5
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Daniel Verkamp has contributed a memfd series ("mm/memfd: add F_SEAL_EXEC") which permits the setting of the memfd execute bit at memfd creation time, with the option of sealing the state of the X bit. - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset() thread-safe for pmd unshare") which addresses a rare race condition related to PMD unsharing. - Several folioification patch serieses from Matthew Wilcox, Vishal Moola, Sidhartha Kumar and Lorenzo Stoakes - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which does perform some memcg maintenance and cleanup work. - SeongJae Park has added DAMOS filtering to DAMON, with the series "mm/damon/core: implement damos filter". These filters provide users with finer-grained control over DAMOS's actions. SeongJae has also done some DAMON cleanup work. - Kairui Song adds a series ("Clean up and fixes for swap"). - Vernon Yang contributed the series "Clean up and refinement for maple tree". - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It adds to MGLRU an LRU of memcgs, to improve the scalability of global reclaim. - David Hildenbrand has added some userfaultfd cleanup work in the series "mm: uffd-wp + change_protection() cleanups". - Christoph Hellwig has removed the generic_writepages() library function in the series "remove generic_writepages". - Baolin Wang has performed some maintenance on the compaction code in his series "Some small improvements for compaction". - Sidhartha Kumar is doing some maintenance work on struct page in his series "Get rid of tail page fields". - David Hildenbrand contributed some cleanup, bugfixing and generalization of pte management and of pte debugging in his series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation flag in the series "Discard __GFP_ATOMIC". - Sergey Senozhatsky has improved zsmalloc's memory utilization with his series "zsmalloc: make zspage chain size configurable". - Joey Gouly has added prctl() support for prohibiting the creation of writeable+executable mappings. The previous BPF-based approach had shortcomings. See "mm: In-kernel support for memory-deny-write-execute (MDWE)". - Waiman Long did some kmemleak cleanup and bugfixing in the series "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF". - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series "mm: multi-gen LRU: improve". - Jiaqi Yan has provided some enhancements to our memory error statistics reporting, mainly by presenting the statistics on a per-node basis. See the series "Introduce per NUMA node memory error statistics". - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog regression in compaction via his series "Fix excessive CPU usage during compaction". - Christoph Hellwig does some vmalloc maintenance work in the series "cleanup vfree and vunmap". - Christoph Hellwig has removed block_device_operations.rw_page() in ths series "remove ->rw_page". - We get some maple_tree improvements and cleanups in Liam Howlett's series "VMA tree type safety and remove __vma_adjust()". - Suren Baghdasaryan has done some work on the maintainability of our vm_flags handling in the series "introduce vm_flags modifier functions". - Some pagemap cleanup and generalization work in Mike Rapoport's series "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and "fixups for generic implementation of pfn_valid()" - Baoquan He has done some work to make /proc/vmallocinfo and /proc/kcore better represent the real state of things in his series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas". - Jason Gunthorpe rationalized the GUP system's interface to the rest of the kernel in the series "Simplify the external interface for GUP". - SeongJae Park wishes to migrate people from DAMON's debugfs interface over to its sysfs interface. To support this, we'll temporarily be printing warnings when people use the debugfs interface. See the series "mm/damon: deprecate DAMON debugfs interface". - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes and clean-ups" series. - Huang Ying has provided a dramatic reduction in migration's TLB flush IPI rates with the series "migrate_pages(): batch TLB flushing". - Arnd Bergmann has some objtool fixups in "objtool warning fixes". * tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits) include/linux/migrate.h: remove unneeded externs mm/memory_hotplug: cleanup return value handing in do_migrate_range() mm/uffd: fix comment in handling pte markers mm: change to return bool for isolate_movable_page() mm: hugetlb: change to return bool for isolate_hugetlb() mm: change to return bool for isolate_lru_page() mm: change to return bool for folio_isolate_lru() objtool: add UACCESS exceptions for __tsan_volatile_read/write kmsan: disable ftrace in kmsan core code kasan: mark addr_has_metadata __always_inline mm: memcontrol: rename memcg_kmem_enabled() sh: initialize max_mapnr m68k/nommu: add missing definition of ARCH_PFN_OFFSET mm: percpu: fix incorrect size in pcpu_obj_full_size() maple_tree: reduce stack usage with gcc-9 and earlier mm: page_alloc: call panic() when memoryless node allocation fails mm: multi-gen LRU: avoid futile retries migrate_pages: move THP/hugetlb migration support check to simplify code migrate_pages: batch flushing TLB migrate_pages: share more code between _unmap and _move ...
2023-02-03mm: implement memory-deny-write-execute as a prctlJoey Gouly1-1/+5
Patch series "mm: In-kernel support for memory-deny-write-execute (MDWE)", v2. The background to this is that systemd has a configuration option called MemoryDenyWriteExecute [2], implemented as a SECCOMP BPF filter. Its aim is to prevent a user task from inadvertently creating an executable mapping that is (or was) writeable. Since such BPF filter is stateless, it cannot detect mappings that were previously writeable but subsequently changed to read-only. Therefore the filter simply rejects any mprotect(PROT_EXEC). The side-effect is that on arm64 with BTI support (Branch Target Identification), the dynamic loader cannot change an ELF section from PROT_EXEC to PROT_EXEC|PROT_BTI using mprotect(). For libraries, it can resort to unmapping and re-mapping but for the main executable it does not have a file descriptor. The original bug report in the Red Hat bugzilla - [3] - and subsequent glibc workaround for libraries - [4]. This series adds in-kernel support for this feature as a prctl PR_SET_MDWE, that is inherited on fork(). The prctl denies PROT_WRITE | PROT_EXEC mappings. Like the systemd BPF filter it also denies adding PROT_EXEC to mappings. However unlike the BPF filter it only denies it if the mapping didn't previous have PROT_EXEC. This allows to PROT_EXEC -> PROT_EXEC | PROT_BTI with mprotect(), which is a problem with the BPF filter. This patch (of 2): The aim of such policy is to prevent a user task from creating an executable mapping that is also writeable. An example of mmap() returning -EACCESS if the policy is enabled: mmap(0, size, PROT_READ | PROT_WRITE | PROT_EXEC, flags, 0, 0); Similarly, mprotect() would return -EACCESS below: addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0); mprotect(addr, size, PROT_READ | PROT_WRITE | PROT_EXEC); The BPF filter that systemd MDWE uses is stateless, and disallows mprotect() with PROT_EXEC completely. This new prctl allows PROT_EXEC to be enabled if it was already PROT_EXEC, which allows the following case: addr = mmap(0, size, PROT_READ | PROT_EXEC, flags, 0, 0); mprotect(addr, size, PROT_READ | PROT_EXEC | PROT_BTI); where PROT_BTI enables branch tracking identification on arm64. Link: https://lkml.kernel.org/r/20230119160344.54358-1-joey.gouly@arm.com Link: https://lkml.kernel.org/r/20230119160344.54358-2-joey.gouly@arm.com Signed-off-by: Joey Gouly <joey.gouly@arm.com> Co-developed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jeremy Linton <jeremy.linton@arm.com> Cc: Kees Cook <keescook@chromium.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Mark Brown <broonie@kernel.org> Cc: nd <nd@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Topi Miettinen <toiwoton@gmail.com> Cc: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-14 02:16:12 +0300