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2024-11-05mm: refactor mm_access() to not return NULLLorenzo Stoakes
mm_access() can return NULL if the mm is not found, but this is handled the same as an error in all callers, with some translating this into an -ESRCH error. Only proc_mem_open() returns NULL if no mm is found, however in this case it is clearer and makes more sense to explicitly handle the error. Additionally we take the opportunity to refactor the function to eliminate unnecessary nesting. Simplify things by simply returning -ESRCH if no mm is found - this both eliminates confusing use of the IS_ERR_OR_NULL() macro, and simplifies callers which would return -ESRCH by returning this error directly. [lorenzo.stoakes@oracle.com: prefer neater pointer error comparison] Link: https://lkml.kernel.org/r/2fae1834-749a-45e1-8594-5e5979cf7103@lucifer.local Link: https://lkml.kernel.org/r/20240924201023.193135-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Suggested-by: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-05sched_ext: Add a missing newline at the end of an error messageTejun Heo
Signed-off-by: Tejun Heo <tj@kernel.org>
2024-11-05perf/core: Add aux_pause, aux_resume, aux_start_pausedAdrian Hunter
Hardware traces, such as instruction traces, can produce a vast amount of trace data, so being able to reduce tracing to more specific circumstances can be useful. The ability to pause or resume tracing when another event happens, can do that. Add ability for an event to "pause" or "resume" AUX area tracing. Add aux_pause bit to perf_event_attr to indicate that, if the event happens, the associated AUX area tracing should be paused. Ditto aux_resume. Do not allow aux_pause and aux_resume to be set together. Add aux_start_paused bit to perf_event_attr to indicate to an AUX area event that it should start in a "paused" state. Add aux_paused to struct hw_perf_event for AUX area events to keep track of the "paused" state. aux_paused is initialized to aux_start_paused. Add PERF_EF_PAUSE and PERF_EF_RESUME modes for ->stop() and ->start() callbacks. Call as needed, during __perf_event_output(). Add aux_in_pause_resume to struct perf_buffer to prevent races with the NMI handler. Pause/resume in NMI context will miss out if it coincides with another pause/resume. To use aux_pause or aux_resume, an event must be in a group with the AUX area event as the group leader. Example (requires Intel PT and tools patches also): $ perf record --kcore -e intel_pt/aux-action=start-paused/k,syscalls:sys_enter_newuname/aux-action=resume/,syscalls:sys_exit_newuname/aux-action=pause/ uname Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.043 MB perf.data ] $ perf script --call-trace uname 30805 [000] 24001.058782799: name: 0x7ffc9c1865b0 uname 30805 [000] 24001.058784424: psb offs: 0 uname 30805 [000] 24001.058784424: cbr: 39 freq: 3904 MHz (139%) uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __x64_sys_newuname uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) down_read uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __cond_resched uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) in_lock_functions uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_sub uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) up_read uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) in_lock_functions uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) preempt_count_sub uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) _copy_to_user uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_to_user_mode uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_work uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) perf_syscall_exit uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_alloc uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_get_recursion_context uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_tp_event uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_update uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) tracing_gen_ctx_irq_test uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_event uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __perf_event_account_interrupt uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __this_cpu_preempt_check uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_output_forward uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_aux_pause uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) ring_buffer_get uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_lock uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_unlock uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) pt_event_stop uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) native_write_msr uname 30805 [000] 24001.058785463: ([kernel.kallsyms]) native_write_msr uname 30805 [000] 24001.058785639: 0x0 Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: James Clark <james.clark@arm.com> Link: https://lkml.kernel.org/r/20241022155920.17511-3-adrian.hunter@intel.com
2024-11-05sched: Enable PREEMPT_DYNAMIC for PREEMPT_RTPeter Zijlstra
In order to enable PREEMPT_DYNAMIC for PREEMPT_RT, remove PREEMPT_RT from the 'Preemption Model' choice. Strictly speaking PREEMPT_RT is not a change in how preemption works, but rather it makes a ton more code preemptible. Notably, take away NONE and VOLUNTARY options for PREEMPT_RT, they make no sense (but are techincally possible). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.441622332@infradead.org
2024-11-05sched: Add Lazy preemption modelPeter Zijlstra
Change fair to use resched_curr_lazy(), which, when the lazy preemption model is selected, will set TIF_NEED_RESCHED_LAZY. This LAZY bit will be promoted to the full NEED_RESCHED bit on tick. As such, the average delay between setting LAZY and actually rescheduling will be TICK_NSEC/2. In short, Lazy preemption will delay preemption for fair class but will function as Full preemption for all the other classes, most notably the realtime (RR/FIFO/DEADLINE) classes. The goal is to bridge the performance gap with Voluntary, such that we might eventually remove that option entirely. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org
2024-11-05sched: Add TIF_NEED_RESCHED_LAZY infrastructurePeter Zijlstra
Add the basic infrastructure to split the TIF_NEED_RESCHED bit in two. Either bit will cause a resched on return-to-user, but only TIF_NEED_RESCHED will drive IRQ preemption. No behavioural change intended. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.219540785@infradead.org
2024-11-05sched/ext: Remove sched_fork() hackThomas Gleixner
Instead of solving the underlying problem of the double invocation of __sched_fork() for idle tasks, sched-ext decided to hack around the issue by partially clearing out the entity struct to preserve the already enqueued node. A provided analysis and solution has been ignored for four months. Now that someone else has taken care of cleaning it up, remove the disgusting hack and clear out the full structure. Remove the comment in the structure declaration as well, as there is no requirement for @node being the last element anymore. Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/87ldy82wkc.ffs@tglx
2024-11-05sched: Initialize idle tasks only onceThomas Gleixner
Idle tasks are initialized via __sched_fork() twice: fork_idle() copy_process() sched_fork() __sched_fork() init_idle() __sched_fork() Instead of cleaning this up, sched_ext hacked around it. Even when analyis and solution were provided in a discussion, nobody cared to clean this up. init_idle() is also invoked from sched_init() to initialize the boot CPU's idle task, which requires the __sched_fork() invocation. But this can be trivially solved by invoking __sched_fork() before init_idle() in sched_init() and removing the __sched_fork() invocation from init_idle(). Do so and clean up the comments explaining this historical leftover. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20241028103142.359584747@linutronix.de
2024-11-05seqlock, treewide: Switch to non-raw seqcount_latch interfaceMarco Elver
Switch all instrumentable users of the seqcount_latch interface over to the non-raw interface. Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org> Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20241104161910.780003-5-elver@google.com
2024-11-05time/sched_clock: Broaden sched_clock()'s instrumentation coverageMarco Elver
Most of sched_clock()'s implementation is ineligible for instrumentation due to relying on sched_clock_noinstr(). Split the implementation off into an __always_inline function __sched_clock(), which is then used by the noinstr and instrumentable version, to allow more of sched_clock() to be covered by various instrumentation. This will allow instrumentation with the various sanitizers (KASAN, KCSAN, KMSAN, UBSAN). For KCSAN, we know that raw seqcount_latch usage without annotations will result in false positive reports: tell it that all of __sched_clock() is "atomic" for the latch reader; later changes in this series will take care of the writers. Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org> Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20241104161910.780003-3-elver@google.com
2024-11-05time/sched_clock: Swap update_clock_read_data() latch writesMarco Elver
Swap the writes to the odd and even copies to make the writer critical section look like all other seqcount_latch writers. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20241104161910.780003-2-elver@google.com
2024-11-04PM: EM: Add min/max available performance state limitsLukasz Luba
On some devices there are HW dependencies for shared frequency and voltage between devices. It will impact Energy Aware Scheduler (EAS) decision, where CPUs share the voltage & frequency domain with other CPUs or devices e.g. - Mid CPUs + Big CPU - Little CPU + L3 cache in DSU - some other device + Little CPUs Detailed explanation of one example: When the L3 cache frequency is increased, the affected Little CPUs might run at higher voltage and frequency. That higher voltage causes higher CPU power and thus more energy is used for running the tasks. This is important for background running tasks, which try to run on energy efficient CPUs. Therefore, add performance state limits which are applied for the device (in this case CPU). This is important on SoCs with HW dependencies mentioned above so that the Energy Aware Scheduler (EAS) does not use performance states outside the valid min-max range for energy calculation. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Link: https://patch.msgid.link/20241030164126.1263793-2-lukasz.luba@arm.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-11-04bpf: Mark raw_tp arguments with PTR_MAYBE_NULLKumar Kartikeya Dwivedi
Arguments to a raw tracepoint are tagged as trusted, which carries the semantics that the pointer will be non-NULL. However, in certain cases, a raw tracepoint argument may end up being NULL. More context about this issue is available in [0]. Thus, there is a discrepancy between the reality, that raw_tp arguments can actually be NULL, and the verifier's knowledge, that they are never NULL, causing explicit NULL checks to be deleted, and accesses to such pointers potentially crashing the kernel. To fix this, mark raw_tp arguments as PTR_MAYBE_NULL, and then special case the dereference and pointer arithmetic to permit it, and allow passing them into helpers/kfuncs; these exceptions are made for raw_tp programs only. Ensure that we don't do this when ref_obj_id > 0, as in that case this is an acquired object and doesn't need such adjustment. The reason we do mask_raw_tp_trusted_reg logic is because other will recheck in places whether the register is a trusted_reg, and then consider our register as untrusted when detecting the presence of the PTR_MAYBE_NULL flag. To allow safe dereference, we enable PROBE_MEM marking when we see loads into trusted pointers with PTR_MAYBE_NULL. While trusted raw_tp arguments can also be passed into helpers or kfuncs where such broken assumption may cause issues, a future patch set will tackle their case separately, as PTR_TO_BTF_ID (without PTR_TRUSTED) can already be passed into helpers and causes similar problems. Thus, they are left alone for now. It is possible that these checks also permit passing non-raw_tp args that are trusted PTR_TO_BTF_ID with null marking. In such a case, allowing dereference when pointer is NULL expands allowed behavior, so won't regress existing programs, and the case of passing these into helpers is the same as above and will be dealt with later. Also update the failure case in tp_btf_nullable selftest to capture the new behavior, as the verifier will no longer cause an error when directly dereference a raw tracepoint argument marked as __nullable. [0]: https://lore.kernel.org/bpf/ZrCZS6nisraEqehw@jlelli-thinkpadt14gen4.remote.csb Reviewed-by: Jiri Olsa <jolsa@kernel.org> Reported-by: Juri Lelli <juri.lelli@redhat.com> Tested-by: Juri Lelli <juri.lelli@redhat.com> Fixes: 3f00c5239344 ("bpf: Allow trusted pointers to be passed to KF_TRUSTED_ARGS kfuncs") Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20241104171959.2938862-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-11-03bpf: Unify resource leak checksKumar Kartikeya Dwivedi
There are similar checks for covering locks, references, RCU read sections and preempt_disable sections in 3 places in the verifer, i.e. for tail calls, bpf_ld_[abs, ind], and exit path (for BPF_EXIT and bpf_throw). Unify all of these into a common check_resource_leak function to avoid code duplication. Also update the error strings in selftests to the new ones in the same change to ensure clean bisection. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20241103225940.1408302-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-11-03bpf: Tighten tail call checks for lingering locks, RCU, preempt_disableKumar Kartikeya Dwivedi
There are three situations when a program logically exits and transfers control to the kernel or another program: bpf_throw, BPF_EXIT, and tail calls. The former two check for any lingering locks and references, but tail calls currently do not. Expand the checks to check for spin locks, RCU read sections and preempt disabled sections. Spin locks are indirectly preventing tail calls as function calls are disallowed, but the checks for preemption and RCU are more relaxed, hence ensure tail calls are prevented in their presence. Fixes: 9bb00b2895cb ("bpf: Add kfunc bpf_rcu_read_lock/unlock()") Fixes: fc7566ad0a82 ("bpf: Introduce bpf_preempt_[disable,enable] kfuncs") Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20241103225940.1408302-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-11-03rcu: Finer-grained grace-period-end checks in rcu_dump_cpu_stacks()Paul E. McKenney
This commit pushes the grace-period-end checks further down into rcu_dump_cpu_stacks(), and also uses lockless checks coupled with finer-grained locking. The result is that the current leaf rcu_node structure's ->lock is acquired only if a stack backtrace might be needed from the current CPU, and is held across only that CPU's backtrace. As a result, if there are no stalled CPUs associated with a given rcu_node structure, then its ->lock will not be acquired at all. On large systems, it is usually (though not always) the case that a small number of CPUs are stalling the current grace period, which means that the ->lock need be acquired only for a small fraction of the rcu_node structures. [ paulmck: Apply Dan Carpenter feedback. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
2024-11-03Merge tag 'timers-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "A single fix for posix CPU timers. When a thread is cloned, the posix CPU timers are not inherited. If the parent has a CPU timer armed the corresponding tick dependency in the tasks tick_dep_mask is set and copied to the new thread, which means the new thread and all decendants will prevent the system to go into full NOHZ operation. Clear the tick dependency mask in copy_process() to fix this" * tag 'timers-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone
2024-11-03Merge tag 'sched-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Thomas Gleixner: - Plug a race between pick_next_task_fair() and try_to_wake_up() where both try to write to the same task, even though both paths hold a runqueue lock, but obviously from different runqueues. The problem is that the store to task::on_rq in __block_task() is visible to try_to_wake_up() which assumes that the task is not queued. Both sides then operate on the same task. Cure it by rearranging __block_task() so the the store to task::on_rq is the last operation on the task. - Prevent a potential NULL pointer dereference in task_numa_work() task_numa_work() iterates the VMAs of a process. A concurrent unmap of the address space can result in a NULL pointer return from vma_next() which is unchecked. Add the missing NULL pointer check to prevent this. - Operate on the correct scheduler policy in task_should_scx() task_should_scx() returns true when a task should be handled by sched EXT. It checks the tasks scheduling policy. This fails when the check is done before a policy has been set. Cure it by handing the policy into task_should_scx() so it operates on the requested value. - Add the missing handling of sched EXT in the delayed dequeue mechanism. This was simply forgotten. * tag 'sched-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/ext: Fix scx vs sched_delayed sched: Pass correct scheduling policy to __setscheduler_class sched/numa: Fix the potential null pointer dereference in task_numa_work() sched: Fix pick_next_task_fair() vs try_to_wake_up() race
2024-11-03Merge tag 'perf-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fix from Thomas Gleixner: "perf_event_clear_cpumask() uses list_for_each_entry_rcu() without being in a RCU read side critical section, which triggers a 'suspicious RCU usage' warning. It turns out that the list walk does not be RCU protected because the write side lock is held in this context. Change it to a regular list walk" * tag 'perf-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix missing RCU reader protection in perf_event_clear_cpumask()
2024-11-03Merge tag 'irq-urgent-2024-11-03' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: - Fix an off-by-one error in the failure path of msi_domain_alloc(), which causes the cleanup loop to terminate early and leaking the first allocated interrupt. - Handle a corner case in GIC-V4 versus a lazily mapped Virtual Processing Element (VPE). If the VPE has not been mapped because the guest has not yet emitted a mapping command, then the set_affinity() callback returns an error code, which causes the vCPU management to fail. Return success in this case without touching the hardware. This will be done later when the guest issues the mapping command. * tag 'irq-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gic-v4: Correctly deal with set_affinity on lazily-mapped VPEs genirq/msi: Fix off-by-one error in msi_domain_alloc()
2024-11-03css_set_fork(): switch to CLASS(fd_raw, ...)Al Viro
reference acquired there by fget_raw() is not stashed anywhere - we could as well borrow instead. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03fdget(), more trivial conversionsAl Viro
all failure exits prior to fdget() leave the scope, all matching fdput() are immediately followed by leaving the scope. [xfs_ioc_commit_range() chunk moved here as well] Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03fdget(), trivial conversionsAl Viro
fdget() is the first thing done in scope, all matching fdput() are immediately followed by leaving the scope. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03fdget_raw() users: switch to CLASS(fd_raw)Al Viro
Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03get rid of perf_fget_light(), convert kernel/events/core.c to CLASS(fd)Al Viro
Lift fdget() and fdput() out of perf_fget_light(), turning it into is_perf_file(struct fd f). The life gets easier in both callers if we do fdget() unconditionally, including the case when we are given -1 instead of a descriptor - that avoids a reassignment in perf_event_open(2) and it avoids a nasty temptation in _perf_ioctl() where we must *not* lift output_event out of scope for output. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-03regularize emptiness checks in fini_module(2) and vfs_dedupe_file_range()Al Viro
With few exceptions emptiness checks are done as fd_file(...) in boolean context (usually something like if (!fd_file(f))...); those will be taken care of later. However, there's a couple of places where we do those checks as 'store fd_file(...) into a variable, then check if this variable is NULL' and those are harder to spot. Get rid of those now. use fd_empty() instead of extracting file and then checking it for NULL. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-11-02timekeeping: Always check for negative motionThomas Gleixner
clocksource_delta() has two variants. One with a check for negative motion, which is only selected by x86. This is a historic leftover as this function was previously used in the time getter hot paths. Since 135225a363ae timekeeping_cycles_to_ns() has unconditional protection against this as a by-product of the protection against 64bit math overflow. clocksource_delta() is only used in the clocksource watchdog and in timekeeping_advance(). The extra conditional there is not hurting anyone. Remove the config option and unconditionally prevent negative motion of the readout. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <jstultz@google.com> Link: https://lore.kernel.org/all/20241031120328.599430157@linutronix.de
2024-11-02timekeeping: Remove CONFIG_DEBUG_TIMEKEEPINGThomas Gleixner
Since 135225a363ae timekeeping_cycles_to_ns() handles large offsets which would lead to 64bit multiplication overflows correctly. It's also protected against negative motion of the clocksource unconditionally, which was exclusive to x86 before. timekeeping_advance() handles large offsets already correctly. That means the value of CONFIG_DEBUG_TIMEKEEPING which analyzed these cases is very close to zero. Remove all of it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <jstultz@google.com> Link: https://lore.kernel.org/all/20241031120328.536010148@linutronix.de
2024-11-02kdb: Fix breakpoint enable to be silent if already enabledNir Lichtman
Fix the breakpoint enable command (be) to a logic that is inline with the breakpoint disable command (bd) in which if the breakpoint is already in an enabled state, do not print the message of enabled again to the user. Also a small nit fix of the new line in a separate print. Signed-off-by: Nir Lichtman <nir@lichtman.org> Link: https://lore.kernel.org/r/20241027204729.GA907155@lichtman.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2024-11-02kdb: Remove fallback interpretation of arbitrary numbers as hexNir Lichtman
Remove logic that enables a fallback of interpreting numbers supplied in KDB CLI to be interpreted as hex without explicit "0x" prefix as this can be confusing for the end users. Suggested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Nir Lichtman <nir@lichtman.org> Link: https://lore.kernel.org/r/20241028192228.GC918454@lichtman.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2024-11-02trace: kdb: Replace simple_strtoul with kstrtoul in kdb_ftdumpYuran Pereira
The function simple_strtoul performs no error checking in scenarios where the input value overflows the intended output variable. This results in this function successfully returning, even when the output does not match the input string (aka the function returns successfully even when the result is wrong). Or as it was mentioned [1], "...simple_strtol(), simple_strtoll(), simple_strtoul(), and simple_strtoull() functions explicitly ignore overflows, which may lead to unexpected results in callers." Hence, the use of those functions is discouraged. This patch replaces all uses of the simple_strtoul with the safer alternatives kstrtoint and kstrtol. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org> [nir: style fixes] Signed-off-by: Nir Lichtman <nir@lichtman.org> Link: https://lore.kernel.org/r/20241028192100.GB918454@lichtman.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2024-11-02kdb: Replace the use of simple_strto with safer kstrto in kdb_mainYuran Pereira
The simple_str* family of functions perform no error checking in scenarios where the input value overflows the intended output variable. This results in these functions successfully returning even when the output does not match the input string. Or as it was mentioned [1], "...simple_strtol(), simple_strtoll(), simple_strtoul(), and simple_strtoull() functions explicitly ignore overflows, which may lead to unexpected results in callers." Hence, the use of those functions is discouraged. This patch replaces all uses of the simple_strto* series of functions with their safer kstrto* alternatives. Side effects of this patch: - Every string to long or long long conversion using kstrto* is now checked for failure. - kstrto* errors are handled with appropriate `KDB_BADINT` wherever applicable. - A good side effect is that we end up saving a few lines of code since unlike in simple_strto* functions, kstrto functions do not need an additional "end pointer" variable, and the return values of the latter can be directly checked in an "if" statement without the need to define additional `ret` or `err` variables. This, of course, results in cleaner, yet still easy to understand code. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull Signed-off-by: Yuran Pereira <yuran.pereira@hotmail.com> [nir: addressed review comments by fixing styling, invalid conversion and a missing error return] Signed-off-by: Nir Lichtman <nir@lichtman.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20241028191916.GA918454@lichtman.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2024-11-01bpf: ensure RCU Tasks Trace GP for sleepable raw tracepoint BPF linksAndrii Nakryiko
Now that kernel supports sleepable tracepoints, the fact that bpf_probe_unregister() is asynchronous, i.e., that it doesn't wait for any in-flight tracepoints to conclude before returning, we now need to delay BPF raw tp link's deallocation and bpf_prog_put() of its underlying BPF program (regardless of program's own sleepable semantics) until after full RCU Tasks Trace GP. With that GP over, we'll have a guarantee that no tracepoint can reach BPF link and thus its BPF program. We use newly added tracepoint_is_faultable() check to know when this RCU Tasks Trace GP is necessary and utilize BPF link's own sleepable flag passed through bpf_link_init_sleepable() initializer. Link: https://lore.kernel.org/20241101181754.782341-3-andrii@kernel.org Tested-by: Jordan Rife <jrife@google.com> Reported-by: Jordan Rife <jrife@google.com> Fixes: a363d27cdbc2 ("tracing: Allow system call tracepoints to handle page faults") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01bpf: decouple BPF link/attach hook and BPF program sleepable semanticsAndrii Nakryiko
BPF link's lifecycle protection scheme depends on both BPF hook and BPF program. If *either* of those require RCU Tasks Trace GP, then we need to go through a chain of GPs before putting BPF program refcount and deallocating BPF link memory. This patch adds bpf_link-specific sleepable flag, which can be set to true even if underlying BPF program is not sleepable itself. If either link->sleepable or link->prog->sleepable is true, we'll go through a chain of RCU Tasks Trace GP and RCU GP before putting BPF program and freeing memory. This will be used to protect BPF link for sleepable (faultable) raw tracepoints in the next patch. Link: https://lore.kernel.org/20241101181754.782341-2-andrii@kernel.org Tested-by: Jordan Rife <jrife@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01bpf: put bpf_link's program when link is safe to be deallocatedAndrii Nakryiko
In general, BPF link's underlying BPF program should be considered to be reachable through attach hook -> link -> prog chain, and, pessimistically, we have to assume that as long as link's memory is not safe to free, attach hook's code might hold a pointer to BPF program and use it. As such, it's not (generally) correct to put link's program early before waiting for RCU GPs to go through. More eager bpf_prog_put() that we currently do is mostly correct due to BPF program's release code doing similar RCU GP waiting, but as will be shown in the following patches, BPF program can be non-sleepable (and, thus, reliant on only "classic" RCU GP), while BPF link's attach hook can have sleepable semantics and needs to be protected by RCU Tasks Trace, and for such cases BPF link has to go through RCU Tasks Trace + "classic" RCU GPs before being deallocated. And so, if we put BPF program early, we might free BPF program before we free BPF link, leading to use-after-free situation. So, this patch defers bpf_prog_put() until we are ready to perform bpf_link's deallocation. At worst, this delays BPF program freeing by one extra RCU GP, but that seems completely acceptable. Alternatively, we'd need more elaborate ways to determine BPF hook, BPF link, and BPF program lifetimes, and how they relate to each other, which seems like an unnecessary complication. Note, for most BPF links we still will perform eager bpf_prog_put() and link dealloc, so for those BPF links there are no observable changes whatsoever. Only BPF links that use deferred dealloc might notice slightly delayed freeing of BPF programs. Also, to reduce code and logic duplication, extract program put + link dealloc logic into bpf_link_dealloc() helper. Link: https://lore.kernel.org/20241101181754.782341-1-andrii@kernel.org Tested-by: Jordan Rife <jrife@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01tracing: Replace strncpy() with strscpy() when copying commJinjie Ruan
Replace the depreciated[1] strncpy() calls with strscpy() when copying comm. Link: https://github.com/KSPP/linux/issues/90 [1] Cc: <mhiramat@kernel.org> Cc: <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20241031120139.1343025-1-ruanjinjie@huawei.com Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01tracing: Fix syscall tracepoint use-after-freeMathieu Desnoyers
The grace period used internally within tracepoint.c:release_probes() uses call_rcu() to batch waiting for quiescence of old probe arrays, rather than using the tracepoint_synchronize_unregister() which blocks while waiting for quiescence. With the introduction of faultable syscall tracepoints, this causes use-after-free issues reproduced with syzkaller. Fix this by using the appropriate call_rcu() or call_rcu_tasks_trace() before invoking the rcu_free_old_probes callback. This can be chosen using the tracepoint_is_faultable() API. A similar issue exists in bpf use of call_rcu(). Fixing this is left to a separate change. Reported-by: syzbot+b390c8062d8387b6272a@syzkaller.appspotmail.com Fixes: a363d27cdbc2 ("tracing: Allow system call tracepoints to handle page faults") Tested-by: Jordan Rife <jrife@google.com> Cc: Michael Jeanson <mjeanson@efficios.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Yonghong Song <yhs@fb.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: bpf@vger.kernel.org Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Jordan Rife <jrife@google.com> Cc: linux-trace-kernel@vger.kernel.org Link: https://lore.kernel.org/20241031152056.744137-4-mathieu.desnoyers@efficios.com Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01tracing: Introduce tracepoint extended structureMathieu Desnoyers
Shrink the struct tracepoint size from 80 bytes to 72 bytes on x86-64 by moving the (typically NULL) regfunc/unregfunc pointers to an extended structure. Tested-by: Jordan Rife <jrife@google.com> Cc: Michael Jeanson <mjeanson@efficios.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Yonghong Song <yhs@fb.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: bpf@vger.kernel.org Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Jordan Rife <jrife@google.com> Cc: linux-trace-kernel@vger.kernel.org Link: https://lore.kernel.org/20241031152056.744137-2-mathieu.desnoyers@efficios.com Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01tracing: Remove TRACE_FLAG_IRQS_NOSUPPORTSebastian Andrzej Siewior
It was possible to enable tracing with no IRQ tracing support. The tracing infrastructure would then record TRACE_FLAG_IRQS_NOSUPPORT as the only tracing flag and show an 'X' in the output. The last user of this feature was PPC32 which managed to implement it during PowerPC merge in 2009. Since then, it was unused and the PPC32 dependency was finally removed in commit 0ea5ee035133a ("tracing: Remove PPC32 wart from config TRACING_SUPPORT"). Since the PowerPC merge the code behind !CONFIG_TRACE_IRQFLAGS_SUPPORT with TRACING enabled can no longer be selected used and the 'X' is not displayed or recorded. Remove the CONFIG_TRACE_IRQFLAGS_SUPPORT from the tracing code. Remove TRACE_FLAG_IRQS_NOSUPPORT. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20241022110112.XJI8I9T2@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-01bpf: Add open coded version of kmem_cache iteratorNamhyung Kim
Add a new open coded iterator for kmem_cache which can be called from a BPF program like below. It doesn't take any argument and traverses all kmem_cache entries. struct kmem_cache *pos; bpf_for_each(kmem_cache, pos) { ... } As it needs to grab slab_mutex, it should be called from sleepable BPF programs only. Also update the existing iterator code to use the open coded version internally as suggested by Andrii. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20241030222819.1800667-1-namhyung@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-11-01tracing: Document tracefs gid mount optionKalesh Singh
Commit ee7f3666995d ("tracefs: Have new files inherit the ownership of their parent") and commit 48b27b6b5191 ("tracefs: Set all files to the same group ownership as the mount option") introduced a new gid mount option that allows specifying a group to apply to all entries in tracefs. Document this in the tracing readme. Cc: Eric Sandeen <sandeen@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Ali Zahraee <ahzahraee@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Howells <dhowells@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/20241030171928.4168869-3-kaleshsingh@google.com Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.12-rc6). Conflicts: drivers/net/wireless/intel/iwlwifi/mvm/mld-mac80211.c cbe84e9ad5e2 ("wifi: iwlwifi: mvm: really send iwl_txpower_constraints_cmd") 188a1bf89432 ("wifi: mac80211: re-order assigning channel in activate links") https://lore.kernel.org/all/20241028123621.7bbb131b@canb.auug.org.au/ net/mac80211/cfg.c c4382d5ca1af ("wifi: mac80211: update the right link for tx power") 8dd0498983ee ("wifi: mac80211: Fix setting txpower with emulate_chanctx") drivers/net/ethernet/intel/ice/ice_ptp_hw.h 6e58c3310622 ("ice: fix crash on probe for DPLL enabled E810 LOM") e4291b64e118 ("ice: Align E810T GPIO to other products") ebb2693f8fbd ("ice: Read SDP section from NVM for pin definitions") ac532f4f4251 ("ice: Cleanup unused declarations") https://lore.kernel.org/all/20241030120524.1ee1af18@canb.auug.org.au/ No adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-31Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfLinus Torvalds
Pull bpf fixes from Daniel Borkmann: - Fix BPF verifier to force a checkpoint when the program's jump history becomes too long (Eduard Zingerman) - Add several fixes to the BPF bits iterator addressing issues like memory leaks and overflow problems (Hou Tao) - Fix an out-of-bounds write in trie_get_next_key (Byeonguk Jeong) - Fix BPF test infra's LIVE_FRAME frame update after a page has been recycled (Toke Høiland-Jørgensen) - Fix BPF verifier and undo the 40-bytes extra stack space for bpf_fastcall patterns due to various bugs (Eduard Zingerman) - Fix a BPF sockmap race condition which could trigger a NULL pointer dereference in sock_map_link_update_prog (Cong Wang) - Fix tcp_bpf_recvmsg_parser to retrieve seq_copied from tcp_sk under the socket lock (Jiayuan Chen) * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: bpf, test_run: Fix LIVE_FRAME frame update after a page has been recycled selftests/bpf: Add three test cases for bits_iter bpf: Use __u64 to save the bits in bits iterator bpf: Check the validity of nr_words in bpf_iter_bits_new() bpf: Add bpf_mem_alloc_check_size() helper bpf: Free dynamically allocated bits in bpf_iter_bits_destroy() bpf: disallow 40-bytes extra stack for bpf_fastcall patterns selftests/bpf: Add test for trie_get_next_key() bpf: Fix out-of-bounds write in trie_get_next_key() selftests/bpf: Test with a very short loop bpf: Force checkpoint when jmp history is too long bpf: fix filed access without lock sock_map: fix a NULL pointer dereference in sock_map_link_update_prog()
2024-10-31arm64: Use SYSTEM_OFF2 PSCI call to power off for hibernateDavid Woodhouse
The PSCI v1.3 specification adds support for a SYSTEM_OFF2 function which is analogous to ACPI S4 state. This will allow hosting environments to determine that a guest is hibernated rather than just powered off, and handle that state appropriately on subsequent launches. Since commit 60c0d45a7f7a ("efi/arm64: use UEFI for system reset and poweroff") the EFI shutdown method is deliberately preferred over PSCI or other methods. So register a SYS_OFF_MODE_POWER_OFF handler which *only* handles the hibernation, leaving the original PSCI SYSTEM_OFF as a last resort via the legacy pm_power_off function pointer. The hibernation code already exports a system_entering_hibernation() function which is be used by the higher-priority handler to check for hibernation. That existing function just returns the value of a static boolean variable from hibernate.c, which was previously only set in the hibernation_platform_enter() code path. Set the same flag in the simpler code path around the call to kernel_power_off() too. An alternative way to hook SYSTEM_OFF2 into the hibernation code would be to register a platform_hibernation_ops structure with an ->enter() method which makes the new SYSTEM_OFF2 call. But that would have the unwanted side-effect of making hibernation take a completely different code path in hibernation_platform_enter(), invoking a lot of special dpm callbacks. Another option might be to add a new SYS_OFF_MODE_HIBERNATE mode, with fallback to SYS_OFF_MODE_POWER_OFF. Or to use the sys_off_data to indicate whether the power off is for hibernation. But this version works and is relatively simple. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20241019172459.2241939-7-dwmw2@infradead.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-10-31timers: Add missing READ_ONCE() in __run_timer_base()Thomas Gleixner
__run_timer_base() checks base::next_expiry without holding base::lock. That can race with a remote CPU updating next_expiry under the lock. This is an intentional and harmless data race, but lacks a READ_ONCE(), so KCSAN complains about this. Add the missing READ_ONCE(). All other places are covered already. Fixes: 79f8b28e85f8 ("timers: Annotate possible non critical data race of next_expiry") Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/all/87a5emyqk0.ffs@tglx Closes: https://lore.kernel.org/oe-lkp/202410301205.ef8e9743-lkp@intel.com
2024-10-31tick: Remove now unneeded low-res tick stop on CPUHP_AP_TICK_DYINGFrederic Weisbecker
The generic clockevent layer now detaches and stops the underlying clockevent from the dying CPU, unifying the tick behaviour for both periodic and oneshot mode on offline CPUs. There is no more need for the tick layer to care about that. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241029125451.54574-4-frederic@kernel.org
2024-10-31clockevents: Shutdown and unregister current clockevents at CPUHP_AP_TICK_DYINGFrederic Weisbecker
The way the clockevent devices are finally stopped while a CPU is offlining is currently chaotic. The layout being by order: 1) tick_sched_timer_dying() stops the tick and the underlying clockevent but only for oneshot case. The periodic tick and its related clockevent still runs. 2) tick_broadcast_offline() detaches and stops the per-cpu oneshot broadcast and append it to the released list. 3) Some individual clockevent drivers stop the clockevents (a second time if the tick is oneshot) 4) Once the CPU is dead, a control CPU remotely detaches and stops (a 3rd time if oneshot mode) the CPU clockevent and adds it to the released list. 5) The released list containing the broadcast device released on step 2) and the remotely detached clockevent from step 4) are unregistered. These random events can be factorized if the current clockevent is detached and stopped by the dying CPU at the generic layer, that is from the dying CPU: a) Stop the tick b) Stop/detach the underlying per-cpu oneshot broadcast clockevent c) Stop/detach the underlying clockevent d) Release / unregister the clockevents from b) and c) e) Release / unregister the remaining clockevents from the dying CPU. This part could be performed by the dying CPU This way the drivers and the tick layer don't need to care about clockevent operations during cpuhotplug down. This also unifies the tick behaviour on offline CPUs between oneshot and periodic modes, avoiding offline ticks altogether for sanity. Adopt the simplification. [ tglx: Remove the WARN_ON() in clockevents_register_device() as that is called from an upcoming CPU before the CPU is marked online ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241029125451.54574-3-frederic@kernel.org
2024-10-31clockevents: Improve clockevents_notify_released() commentFrederic Weisbecker
When a new clockevent device is added and replaces a previous device, the latter is put into the released list. Then the released list is added back. This may look counter-intuitive but the reason is that released device might be suitable for other uses. For example a released CPU regular clockevent can be a better replacement for the current broadcast event. Similarly a released broadcast clockevent can be a better replacement for the current regular clockevent of a given CPU. Improve comments stating about these subtleties. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241029125451.54574-2-frederic@kernel.org
2024-10-31kprobes: Use struct_size() in __get_insn_slot()Nathan Chancellor
__get_insn_slot() allocates 'struct kprobe_insn_page' using a custom structure size calculation macro, KPROBE_INSN_PAGE_SIZE. Replace KPROBE_INSN_PAGE_SIZE with the struct_size() macro, which is the preferred way to calculate the size of flexible structures in the kernel because it handles overflow and makes it easier to change and audit how flexible structures are allocated across the entire tree. Link: https://lore.kernel.org/all/20241030-kprobes-fix-counted-by-annotation-v1-2-8f266001fad0@kernel.org/ (Masami modofied this to be applicable without the 1st patch in the series.) Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-10-31kprobes: Cleanup collect_one_slot() and __disable_kprobe()Jinjie Ruan
If kip->nused is not zero, collect_one_slot() return false, otherwise do a lot of linked list operations, reverse the processing order to make the code if nesting more concise. __disable_kprobe() is the same as well. Link: https://lore.kernel.org/all/20240813115334.3922580-4-ruanjinjie@huawei.com/ Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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