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2024-10-08cgroup/bpf: use a dedicated workqueue for cgroup bpf destructionChen Ridong
A hung_task problem shown below was found: INFO: task kworker/0:0:8 blocked for more than 327 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Workqueue: events cgroup_bpf_release Call Trace: <TASK> __schedule+0x5a2/0x2050 ? find_held_lock+0x33/0x100 ? wq_worker_sleeping+0x9e/0xe0 schedule+0x9f/0x180 schedule_preempt_disabled+0x25/0x50 __mutex_lock+0x512/0x740 ? cgroup_bpf_release+0x1e/0x4d0 ? cgroup_bpf_release+0xcf/0x4d0 ? process_scheduled_works+0x161/0x8a0 ? cgroup_bpf_release+0x1e/0x4d0 ? mutex_lock_nested+0x2b/0x40 ? __pfx_delay_tsc+0x10/0x10 mutex_lock_nested+0x2b/0x40 cgroup_bpf_release+0xcf/0x4d0 ? process_scheduled_works+0x161/0x8a0 ? trace_event_raw_event_workqueue_execute_start+0x64/0xd0 ? process_scheduled_works+0x161/0x8a0 process_scheduled_works+0x23a/0x8a0 worker_thread+0x231/0x5b0 ? __pfx_worker_thread+0x10/0x10 kthread+0x14d/0x1c0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x59/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> This issue can be reproduced by the following pressuse test: 1. A large number of cpuset cgroups are deleted. 2. Set cpu on and off repeatly. 3. Set watchdog_thresh repeatly. The scripts can be obtained at LINK mentioned above the signature. The reason for this issue is cgroup_mutex and cpu_hotplug_lock are acquired in different tasks, which may lead to deadlock. It can lead to a deadlock through the following steps: 1. A large number of cpusets are deleted asynchronously, which puts a large number of cgroup_bpf_release works into system_wq. The max_active of system_wq is WQ_DFL_ACTIVE(256). Consequently, all active works are cgroup_bpf_release works, and many cgroup_bpf_release works will be put into inactive queue. As illustrated in the diagram, there are 256 (in the acvtive queue) + n (in the inactive queue) works. 2. Setting watchdog_thresh will hold cpu_hotplug_lock.read and put smp_call_on_cpu work into system_wq. However step 1 has already filled system_wq, 'sscs.work' is put into inactive queue. 'sscs.work' has to wait until the works that were put into the inacvtive queue earlier have executed (n cgroup_bpf_release), so it will be blocked for a while. 3. Cpu offline requires cpu_hotplug_lock.write, which is blocked by step 2. 4. Cpusets that were deleted at step 1 put cgroup_release works into cgroup_destroy_wq. They are competing to get cgroup_mutex all the time. When cgroup_metux is acqured by work at css_killed_work_fn, it will call cpuset_css_offline, which needs to acqure cpu_hotplug_lock.read. However, cpuset_css_offline will be blocked for step 3. 5. At this moment, there are 256 works in active queue that are cgroup_bpf_release, they are attempting to acquire cgroup_mutex, and as a result, all of them are blocked. Consequently, sscs.work can not be executed. Ultimately, this situation leads to four processes being blocked, forming a deadlock. system_wq(step1) WatchDog(step2) cpu offline(step3) cgroup_destroy_wq(step4) ... 2000+ cgroups deleted asyn 256 actives + n inactives __lockup_detector_reconfigure P(cpu_hotplug_lock.read) put sscs.work into system_wq 256 + n + 1(sscs.work) sscs.work wait to be executed warting sscs.work finish percpu_down_write P(cpu_hotplug_lock.write) ...blocking... css_killed_work_fn P(cgroup_mutex) cpuset_css_offline P(cpu_hotplug_lock.read) ...blocking... 256 cgroup_bpf_release mutex_lock(&cgroup_mutex); ..blocking... To fix the problem, place cgroup_bpf_release works on a dedicated workqueue which can break the loop and solve the problem. System wqs are for misc things which shouldn't create a large number of concurrent work items. If something is going to generate >WQ_DFL_ACTIVE(256) concurrent work items, it should use its own dedicated workqueue. Fixes: 4bfc0bb2c60e ("bpf: decouple the lifetime of cgroup_bpf from cgroup itself") Cc: stable@vger.kernel.org # v5.3+ Link: https://lore.kernel.org/cgroups/e90c32d2-2a85-4f28-9154-09c7d320cb60@huawei.com/T/#t Tested-by: Vishal Chourasia <vishalc@linux.ibm.com> Signed-off-by: Chen Ridong <chenridong@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-10-07bpf: Fix memory leak in bpf_core_applyJiri Olsa
We need to free specs properly. Fixes: 3d2786d65aaa ("bpf: correctly handle malformed BPF_CORE_TYPE_ID_LOCAL relos") Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20241007160958.607434-1-jolsa@kernel.org
2024-10-07sched_ext, scx_qmap: Add and use SCX_ENQ_CPU_SELECTEDTejun Heo
scx_qmap and other schedulers in the SCX repo are using SCX_ENQ_WAKEUP to tell whether ops.select_cpu() was called. This is incorrect as ops.select_cpu() can be skipped in the wakeup path and leads to e.g. incorrectly skipping direct dispatch for tasks that are bound to a single CPU. sched core has been updated to specify ENQUEUE_RQ_SELECTED if ->select_task_rq() was called. Map it to SCX_ENQ_CPU_SELECTED and update scx_qmap to test it instead of SCX_ENQ_WAKEUP. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com> Cc: Daniel Hodges <hodges.daniel.scott@gmail.com> Cc: Changwoo Min <multics69@gmail.com> Cc: Andrea Righi <andrea.righi@linux.dev> Cc: Dan Schatzberg <schatzberg.dan@gmail.com>
2024-10-07sched/core: Add ENQUEUE_RQ_SELECTED to indicate whether ->select_task_rq() ↵Tejun Heo
was called During ttwu, ->select_task_rq() can be skipped if only one CPU is allowed or migration is disabled. sched_ext schedulers may perform operations such as direct dispatch from ->select_task_rq() path and it is useful for them to know whether ->select_task_rq() was skipped in the ->enqueue_task() path. Currently, sched_ext schedulers are using ENQUEUE_WAKEUP for this purpose and end up assuming incorrectly that ->select_task_rq() was called for tasks that are bound to a single CPU or migration disabled. Make select_task_rq() indicate whether ->select_task_rq() was called by setting WF_RQ_SELECTED in *wake_flags and make ttwu_do_activate() map that to ENQUEUE_RQ_SELECTED for ->enqueue_task(). This will be used by sched_ext to fix ->select_task_rq() skip detection. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com>
2024-10-07sched/core: Make select_task_rq() take the pointer to wake_flags instead of ↵Tejun Heo
value This will be used to allow select_task_rq() to indicate whether ->select_task_rq() was called by modifying *wake_flags. This makes try_to_wake_up() call all functions that take wake_flags with WF_TTWU set. Previously, only select_task_rq() was. Using the same flags is more consistent, and, as the flag is only tested by ->select_task_rq() implementations, it doesn't cause any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com>
2024-10-07remove pointless includes of <linux/fdtable.h>Al Viro
some of those used to be needed, some had been cargo-culted for no reason... Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-10-07get rid of ...lookup...fdget_rcu() familyAl Viro
Once upon a time, predecessors of those used to do file lookup without bumping a refcount, provided that caller held rcu_read_lock() across the lookup and whatever it wanted to read from the struct file found. When struct file allocation switched to SLAB_TYPESAFE_BY_RCU, that stopped being feasible and these primitives started to bump the file refcount for lookup result, requiring the caller to call fput() afterwards. But that turned them pointless - e.g. rcu_read_lock(); file = lookup_fdget_rcu(fd); rcu_read_unlock(); is equivalent to file = fget_raw(fd); and all callers of lookup_fdget_rcu() are of that form. Similarly, task_lookup_fdget_rcu() calls can be replaced with calling fget_task(). task_lookup_next_fdget_rcu() doesn't have direct counterparts, but its callers would be happier if we replaced it with an analogue that deals with RCU internally. Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-10-07uprobes: fold xol_take_insn_slot() into xol_get_insn_slot()Oleg Nesterov
After the previous change xol_take_insn_slot() becomes trivial, kill it. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241001142503.GA13633@redhat.com
2024-10-07uprobes: kill xol_area->slot_countOleg Nesterov
Add the new helper, xol_get_slot_nr() which does find_first_zero_bit() + test_and_set_bit(). xol_take_insn_slot() can wait for the "xol_get_slot_nr() < UINSNS_PER_PAGE" event instead of "area->slot_count < UINSNS_PER_PAGE". So we can kill area->slot_count and avoid atomic_inc() + atomic_dec(), this simplifies the code and can slightly improve the performance. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241001142458.GA13629@redhat.com
2024-10-07uprobes: deny mremap(xol_vma)Oleg Nesterov
kernel/events/uprobes.c assumes that xol_area->vaddr is always correct but a malicious application can remap its "[uprobes]" vma to another adress to confuse the kernel. Introduce xol_mremap() to make this impossible. With this change utask->xol_vaddr in xol_free_insn_slot() can't be invalid, we can turn the offset check into WARN_ON_ONCE(offset >= PAGE_SIZE). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144258.GA9492@redhat.com
2024-10-07uprobes: pass utask to xol_get_insn_slot() and xol_free_insn_slot()Oleg Nesterov
Add the "struct uprobe_task *utask" argument to xol_get_insn_slot() and xol_free_insn_slot(), their callers already have it so we can avoid the unnecessary dereference and simplify the code. Kill the "tsk" argument of xol_free_insn_slot(), it is always current. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144253.GA9487@redhat.com
2024-10-07uprobes: move the initialization of utask->xol_vaddr from pre_ssout() to ↵Oleg Nesterov
xol_get_insn_slot() This simplifies the code and makes xol_get_insn_slot() symmetric with xol_free_insn_slot() which clears utask->xol_vaddr. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144248.GA9483@redhat.com
2024-10-07uprobes: simplify xol_take_insn_slot() and its callerOleg Nesterov
The do / while (slot_nr >= UINSNS_PER_PAGE) loop in xol_take_insn_slot() makes no sense, the checked condition is always true. Change this code to use the "for (;;)" loop, this way we do not need to change slot_nr if test_and_set_bit() fails. Also, kill the unnecessary xol_vaddr != NULL check in xol_get_insn_slot(), xol_take_insn_slot() never returns NULL. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144244.GA9480@redhat.com
2024-10-07uprobes: kill the unnecessary put_uprobe/xol_free_insn_slot in ↵Oleg Nesterov
uprobe_free_utask() If pre_ssout() succeeds and sets utask->active_uprobe and utask->xol_vaddr the task must not exit until it calls handle_singlestep() which does the necessary put_uprobe() and xol_free_insn_slot(). Remove put_uprobe() and xol_free_insn_slot() from uprobe_free_utask(). With this change xol_free_insn_slot() can't hit xol_area/utask/xol_vaddr == NULL, we can kill the unnecessary checks checks and simplify this function more. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144239.GA9475@redhat.com
2024-10-07uprobes: sanitiize xol_free_insn_slot()Oleg Nesterov
1. Clear utask->xol_vaddr unconditionally, even if this addr is not valid, xol_free_insn_slot() should never return with utask->xol_vaddr != NULL. 2. Add a comment to explain why do we need to validate slot_addr. 3. Simplify the validation above. We can simply check offset < PAGE_SIZE, unsigned underflows are fine, it should work if slot_addr < area->vaddr. 4. Kill the unnecessary "slot_nr >= UINSNS_PER_PAGE" check, slot_nr must be valid if offset < PAGE_SIZE. The next patches will cleanup this function even more. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144235.GA9471@redhat.com
2024-10-07uprobes: don't abuse get_utask() in pre_ssout() and prepare_uretprobe()Oleg Nesterov
handle_swbp() calls get_utask() before prepare_uretprobe() or pre_ssout() can be called, they can simply use current->utask which can't be NULL. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240929144230.GA9468@redhat.com
2024-10-07uprobes: switch to RCU Tasks Trace flavor for better performanceAndrii Nakryiko
This patch switches uprobes SRCU usage to RCU Tasks Trace flavor, which is optimized for more lightweight and quick readers (at the expense of slower writers, which for uprobes is a fine tradeof) and has better performance and scalability with number of CPUs. Similarly to baseline vs SRCU, we've benchmarked SRCU-based implementation vs RCU Tasks Trace implementation. SRCU ==== uprobe-nop ( 1 cpus): 3.276 ± 0.005M/s ( 3.276M/s/cpu) uprobe-nop ( 2 cpus): 4.125 ± 0.002M/s ( 2.063M/s/cpu) uprobe-nop ( 4 cpus): 7.713 ± 0.002M/s ( 1.928M/s/cpu) uprobe-nop ( 8 cpus): 8.097 ± 0.006M/s ( 1.012M/s/cpu) uprobe-nop (16 cpus): 6.501 ± 0.056M/s ( 0.406M/s/cpu) uprobe-nop (32 cpus): 4.398 ± 0.084M/s ( 0.137M/s/cpu) uprobe-nop (64 cpus): 6.452 ± 0.000M/s ( 0.101M/s/cpu) uretprobe-nop ( 1 cpus): 2.055 ± 0.001M/s ( 2.055M/s/cpu) uretprobe-nop ( 2 cpus): 2.677 ± 0.000M/s ( 1.339M/s/cpu) uretprobe-nop ( 4 cpus): 4.561 ± 0.003M/s ( 1.140M/s/cpu) uretprobe-nop ( 8 cpus): 5.291 ± 0.002M/s ( 0.661M/s/cpu) uretprobe-nop (16 cpus): 5.065 ± 0.019M/s ( 0.317M/s/cpu) uretprobe-nop (32 cpus): 3.622 ± 0.003M/s ( 0.113M/s/cpu) uretprobe-nop (64 cpus): 3.723 ± 0.002M/s ( 0.058M/s/cpu) RCU Tasks Trace =============== uprobe-nop ( 1 cpus): 3.396 ± 0.002M/s ( 3.396M/s/cpu) uprobe-nop ( 2 cpus): 4.271 ± 0.006M/s ( 2.135M/s/cpu) uprobe-nop ( 4 cpus): 8.499 ± 0.015M/s ( 2.125M/s/cpu) uprobe-nop ( 8 cpus): 10.355 ± 0.028M/s ( 1.294M/s/cpu) uprobe-nop (16 cpus): 7.615 ± 0.099M/s ( 0.476M/s/cpu) uprobe-nop (32 cpus): 4.430 ± 0.007M/s ( 0.138M/s/cpu) uprobe-nop (64 cpus): 6.887 ± 0.020M/s ( 0.108M/s/cpu) uretprobe-nop ( 1 cpus): 2.174 ± 0.001M/s ( 2.174M/s/cpu) uretprobe-nop ( 2 cpus): 2.853 ± 0.001M/s ( 1.426M/s/cpu) uretprobe-nop ( 4 cpus): 4.913 ± 0.002M/s ( 1.228M/s/cpu) uretprobe-nop ( 8 cpus): 5.883 ± 0.002M/s ( 0.735M/s/cpu) uretprobe-nop (16 cpus): 5.147 ± 0.001M/s ( 0.322M/s/cpu) uretprobe-nop (32 cpus): 3.738 ± 0.008M/s ( 0.117M/s/cpu) uretprobe-nop (64 cpus): 4.397 ± 0.002M/s ( 0.069M/s/cpu) Peak throughput for uprobes increases from 8 mln/s to 10.3 mln/s (+28%!), and for uretprobes from 5.3 mln/s to 5.8 mln/s (+11%), as we have more work to do on uretprobes side. Even single-thread (no contention) performance is slightly better: 3.276 mln/s to 3.396 mln/s (+3.5%) for uprobes, and 2.055 mln/s to 2.174 mln/s (+5.8%) for uretprobes. We also select TASKS_TRACE_RCU for UPROBES in Kconfig due to the new dependency. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lkml.kernel.org/r/20240910174312.3646590-1-andrii@kernel.org
2024-10-07sched/wait: Remove unused bit_wait_io_timeoutDr. David Alan Gilbert
bit_wait_io_timeout has been unused since 2016's commit 62906027091f ("mm: add PageWaiters indicating tasks are waiting for a page bit") Remove it. Signed-off-by: "Dr. David Alan Gilbert" <linux@treblig.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com> Link: https://lore.kernel.org/r/20241001234016.231696-1-linux@treblig.org
2024-10-07sched/fair: fix the comment for PREEMPT_SHORTHuang Shijie
We do not have RESPECT_SLICE, we only have RUN_TO_PARITY. Change RESPECT_SLICE to RUN_TO_PARITY, makes it more clear. Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com> Link: https://lkml.kernel.org/r/20241001070456.10939-1-shijie@os.amperecomputing.com
2024-10-07sched/fair: optimize the PLACE_LAG when se->vlag is zeroHuang Shijie
When PLACE_LAG is enabled, from the relationship: vl_i = (W + w_i)*vl'_i / W we know that if vl'_i(se->vlag) is zero, the vl_i is zero too. So if se->vlag is zero, there is no need to waste cycles to do the calculation. Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com> Link: https://lkml.kernel.org/r/20241001070021.10626-1-shijie@os.amperecomputing.com
2024-10-07sched/fair: remove the DOUBLE_TICK featureHuang Shijie
The patch "5e963f2bd46 sched/fair: Commit to EEVDF" removed the code following the DOUBLE_TICK: - - if (!sched_feat(EEVDF) && cfs_rq->nr_running > 1) - check_preempt_tick(cfs_rq, curr); The DOUBLE_TICK feature becomes dead code now, so remove it. Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: "Christoph Lameter (Ampere)" <cl@linux.com> Reviewed-by: Vishal Chourasia <vishalc@linux.ibm.com> Link: https://lore.kernel.org/r/20241001065451.10356-1-shijie@os.amperecomputing.com
2024-10-07softirq: use bit waits instead of var waits.NeilBrown
The waiting in softirq.c is always waiting for a bit to be cleared. This makes the bit wait functions seem more suitable. By switching over we can rid of all explicit barriers. We also use wait_on_bit_lock() to avoid an explicit loop. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240925053405.3960701-8-neilb@suse.de
2024-10-07sched: Document wait_var_event() family of functions and wake_up_var()NeilBrown
wake_up_var(), wait_var_event() and related interfaces are not documented but have important ordering requirements. This patch adds documentation and makes these requirements explicit. The return values for those wait_var_event_* functions which return a value are documented. Note that these are, perhaps surprisingly, sometimes different from comparable wait_on_bit() functions. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240925053405.3960701-4-neilb@suse.de
2024-10-07sched: Improve documentation for wake_up_bit/wait_on_bit family of functionsNeilBrown
This patch revises the documention for wake_up_bit(), clear_and_wake_up_bit(), and all the wait_on_bit() family of functions. The new documentation places less emphasis on the pool of waitqueues used (an implementation detail) and focuses instead on details of how the functions behave. The barriers included in the wait functions and clear_and_wake_up_bit() and those required for wake_up_bit() are spelled out more clearly. The error statuses returned are given explicitly. The fact that the wait_on_bit_lock() function sets the bit is made more obvious. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240925053405.3960701-3-neilb@suse.de
2024-10-07sched: change wake_up_bit() and related function to expect unsigned long *NeilBrown
wake_up_bit() currently allows a "void *". While this isn't strictly a problem as the address is never dereferenced, it is inconsistent with the corresponding wait_on_bit() which requires "unsigned long *" and does dereference the pointer. Any code that needs to wait for a change in something other than an unsigned long would be better served by wake_up_var()/wait_var_event(). This patch changes all related "void *" to "unsigned long *". Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240925053405.3960701-2-neilb@suse.de
2024-10-07locking/spinlocks: Make __raw_* lock ops staticGeert Uytterhoeven
If CONFIG_GENERIC_LOCKBREAK=y and CONFIG_DEBUG_LOCK_ALLOC=n (e.g. sh/sdk7786_defconfig): kernel/locking/spinlock.c:68:17: warning: no previous prototype for '__raw_spin_lock' [-Wmissing-prototypes] kernel/locking/spinlock.c:80:26: warning: no previous prototype for '__raw_spin_lock_irqsave' [-Wmissing-prototypes] kernel/locking/spinlock.c:98:17: warning: no previous prototype for '__raw_spin_lock_irq' [-Wmissing-prototypes] kernel/locking/spinlock.c:103:17: warning: no previous prototype for '__raw_spin_lock_bh' [-Wmissing-prototypes] kernel/locking/spinlock.c:68:17: warning: no previous prototype for '__raw_read_lock' [-Wmissing-prototypes] kernel/locking/spinlock.c:80:26: warning: no previous prototype for '__raw_read_lock_irqsave' [-Wmissing-prototypes] kernel/locking/spinlock.c:98:17: warning: no previous prototype for '__raw_read_lock_irq' [-Wmissing-prototypes] kernel/locking/spinlock.c:103:17: warning: no previous prototype for '__raw_read_lock_bh' [-Wmissing-prototypes] kernel/locking/spinlock.c:68:17: warning: no previous prototype for '__raw_write_lock' [-Wmissing-prototypes] kernel/locking/spinlock.c:80:26: warning: no previous prototype for '__raw_write_lock_irqsave' [-Wmissing-prototypes] kernel/locking/spinlock.c:98:17: warning: no previous prototype for '__raw_write_lock_irq' [-Wmissing-prototypes] kernel/locking/spinlock.c:103:17: warning: no previous prototype for '__raw_write_lock_bh' [-Wmissing-prototypes] All __raw_* lock ops are internal functions without external callers. Hence fix this by making them static. Note that if CONFIG_GENERIC_LOCKBREAK=y, no lock ops are inlined, as all of CONFIG_INLINE_*_LOCK* depend on !GENERIC_LOCKBREAK. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lkml.kernel.org/r/7201d7fb408375c6c4df541270d787b1b4a32354.1727879348.git.geert+renesas@glider.be
2024-10-06Merge branch 'timers/vfs' into timers/coreThomas Gleixner
Pick up the VFS specific interfaces so further timekeeping changes can be based on them.
2024-10-06timekeeping: Add percpu counter for tracking floor swap eventsJeff Layton
The mgtime_floor value is a global variable for tracking the latest fine-grained timestamp handed out. Because it's a global, track the number of times that a new floor value is assigned. Add a new percpu counter to the timekeeping code to track the number of floor swap events that have occurred. A later patch will add a debugfs file to display this counter alongside other stats involving multigrain timestamps. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Randy Dunlap <rdunlap@infradead.org> # documentation bits Link: https://lore.kernel.org/all/20241002-mgtime-v10-2-d1c4717f5284@kernel.org
2024-10-06timekeeping: Add interfaces for handling timestamps with a floor valueJeff Layton
Multigrain timestamps allow the kernel to use fine-grained timestamps when an inode's attributes is being actively observed via ->getattr(). With this support, it's possible for a file to get a fine-grained timestamp, and another modified after it to get a coarse-grained stamp that is earlier than the fine-grained time. If this happens then the files can appear to have been modified in reverse order, which breaks VFS ordering guarantees [1]. To prevent this, maintain a floor value for multigrain timestamps. Whenever a fine-grained timestamp is handed out, record it, and when later coarse-grained stamps are handed out, ensure they are not earlier than that value. If the coarse-grained timestamp is earlier than the fine-grained floor, return the floor value instead. Add a static singleton atomic64_t into timekeeper.c that is used to keep track of the latest fine-grained time ever handed out. This is tracked as a monotonic ktime_t value to ensure that it isn't affected by clock jumps. Because it is updated at different times than the rest of the timekeeper object, the floor value is managed independently of the timekeeper via a cmpxchg() operation, and sits on its own cacheline. Add two new public interfaces: - ktime_get_coarse_real_ts64_mg() fills a timespec64 with the later of the coarse-grained clock and the floor time - ktime_get_real_ts64_mg() gets the fine-grained clock value, and tries to swap it into the floor. A timespec64 is filled with the result. The floor value is global and updated via a single try_cmpxchg(). If that fails then the operation raced with a concurrent update. Any concurrent update must be later than the existing floor value, so any racing tasks can accept any resulting floor value without retrying. [1]: POSIX requires that files be stamped with realtime clock values, and makes no provision for dealing with backward clock jumps. If a backward realtime clock jump occurs, then files can appear to have been modified in reverse order. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Randy Dunlap <rdunlap@infradead.org> # documentation bits Acked-by: John Stultz <jstultz@google.com> Link: https://lore.kernel.org/all/20241002-mgtime-v10-1-d1c4717f5284@kernel.org
2024-10-05function_graph: Remove unnecessary initialization in ftrace_graph_ret_addr()Oleg Nesterov
After the commit 29c1c24a2707 ("function_graph: Fix up ftrace_graph_ret_addr()") ftrace_graph_ret_addr() doesn't need to initialize "int i" at the start. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Puranjay Mohan <puranjay@kernel.org> Link: https://lore.kernel.org/20240916175818.GA28944@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-05function_graph: Support recording and printing the function return addressDonglin Peng
When using function_graph tracer to analyze the flow of kernel function execution, it is often necessary to quickly locate the exact line of code where the call occurs. While this may be easy at times, it can be more time-consuming when some functions are inlined or the flow is too long. This feature aims to simplify the process by recording the return address of traced funcions and printing it when outputing trace logs. To enhance human readability, the prefix 'ret=' is used for the kernel return value, while '<-' serves as the prefix for the return address in trace logs to make it look more like the function tracer. A new trace option named 'funcgraph-retaddr' has been introduced, and the existing option 'sym-addr' can be used to control the format of the return address. See below logs with both funcgraph-retval and funcgraph-retaddr enabled. 0) | load_elf_binary() { /* <-bprm_execve+0x249/0x600 */ 0) | load_elf_phdrs() { /* <-load_elf_binary+0x84/0x1730 */ 0) | __kmalloc_noprof() { /* <-load_elf_phdrs+0x4a/0xb0 */ 0) 3.657 us | __cond_resched(); /* <-__kmalloc_noprof+0x28c/0x390 ret=0x0 */ 0) + 24.335 us | } /* __kmalloc_noprof ret=0xffff8882007f3000 */ 0) | kernel_read() { /* <-load_elf_phdrs+0x6c/0xb0 */ 0) | rw_verify_area() { /* <-kernel_read+0x2b/0x50 */ 0) | security_file_permission() { /* <-kernel_read+0x2b/0x50 */ 0) | selinux_file_permission() { /* <-security_file_permission+0x26/0x40 */ 0) | __inode_security_revalidate() { /* <-selinux_file_permission+0x6d/0x140 */ 0) 2.034 us | __cond_resched(); /* <-__inode_security_revalidate+0x5f/0x80 ret=0x0 */ 0) 6.602 us | } /* __inode_security_revalidate ret=0x0 */ 0) 2.214 us | avc_policy_seqno(); /* <-selinux_file_permission+0x107/0x140 ret=0x0 */ 0) + 16.670 us | } /* selinux_file_permission ret=0x0 */ 0) + 20.809 us | } /* security_file_permission ret=0x0 */ 0) + 25.217 us | } /* rw_verify_area ret=0x0 */ 0) | __kernel_read() { /* <-load_elf_phdrs+0x6c/0xb0 */ 0) | ext4_file_read_iter() { /* <-__kernel_read+0x160/0x2e0 */ Then, we can use the faddr2line to locate the source code, for example: $ ./scripts/faddr2line ./vmlinux load_elf_phdrs+0x6c/0xb0 load_elf_phdrs+0x6c/0xb0: elf_read at fs/binfmt_elf.c:471 (inlined by) load_elf_phdrs at fs/binfmt_elf.c:531 Link: https://lore.kernel.org/20240915032912.1118397-1-dolinux.peng@gmail.com Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202409150605.HgUmU8ea-lkp@intel.com/ Signed-off-by: Donglin Peng <dolinux.peng@gmail.com> [ Rebased to handle text_delta offsets ] Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-04rv: Fix a typoAndrew Kreimer
Fix a typo in comments. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20240911114349.20449-1-algonell@gmail.com Reported-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Kreimer <algonell@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-04sched_ext: scx_cgroup_exit() may be called without successful scx_cgroup_init()Tejun Heo
568894edbe48 ("sched_ext: Add scx_cgroup_enabled to gate cgroup operations and fix scx_tg_online()") assumed that scx_cgroup_exit() is only called after scx_cgroup_init() finished successfully. This isn't true. scx_cgroup_exit() can be called without scx_cgroup_init() being called at all or after scx_cgroup_init() failed in the middle. As init state is tracked per cgroup, scx_cgroup_exit() can be used safely to clean up in all cases. Remove the incorrect WARN_ON_ONCE(). Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 568894edbe48 ("sched_ext: Add scx_cgroup_enabled to gate cgroup operations and fix scx_tg_online()")
2024-10-04sched_ext: Improve error reporting during loadingTejun Heo
When the BPF scheduler fails, ops.exit() allows rich error reporting through scx_exit_info. Use scx.exit() path consistently for all failures which can be caused by the BPF scheduler: - scx_ops_error() is called after ops.init() and ops.cgroup_init() failure to record error information. - ops.init_task() failure now uses scx_ops_error() instead of pr_err(). - The err_disable path updated to automatically trigger scx_ops_error() to cover cases that the error message hasn't already been generated and always return 0 indicating init success so that the error is reported through ops.exit(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David Vernet <void@manifault.com> Cc: Daniel Hodges <hodges.daniel.scott@gmail.com> Cc: Changwoo Min <multics69@gmail.com> Cc: Andrea Righi <andrea.righi@linux.dev> Cc: Dan Schatzberg <schatzberg.dan@gmail.com>
2024-10-04Merge tag 'trace-v6.12-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix tp_printk command line option crashing the kernel With the code that can handle a buffer from a previous boot, the trace_check_vprintf() needed access to the delta of the address space used by the old buffer and the current buffer. To do so, the trace_array (tr) parameter was used. But when tp_printk is enabled on the kernel command line, no trace buffer is used and the trace event is sent directly to printk(). That meant the tr field of the iterator descriptor was NULL, and since tp_printk still uses trace_check_vprintf() it caused a NULL dereference. - Add ptrace.h include to x86 ftrace file for completeness - Fix rtla installation when done with out-of-tree build - Fix the help messages in rtla that were incorrect - Several fixes to fix races with the timerlat and hwlat code Several locking issues were discovered with the coordination between timerlat kthread creation and hotplug. As timerlat has callbacks from hotplug code to start kthreads when CPUs come online. There are also locking issues with grabbing the cpu_read_lock() and the locks within timerlat. * tag 'trace-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing/hwlat: Fix a race during cpuhp processing tracing/timerlat: Fix a race during cpuhp processing tracing/timerlat: Drop interface_lock in stop_kthread() tracing/timerlat: Fix duplicated kthread creation due to CPU online/offline x86/ftrace: Include <asm/ptrace.h> rtla: Fix the help text in osnoise and timerlat top tools tools/rtla: Fix installation from out-of-tree build tracing: Fix trace_check_vprintf() when tp_printk is used
2024-10-04Merge tag 'slab-for-6.12-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab Pull slab fixes from Vlastimil Babka: "Fixes for issues introduced in this merge window: kobject memory leak, unsupressed warning and possible lockup in new slub_kunit tests, misleading code in kvfree_rcu_queue_batch()" * tag 'slab-for-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: slub/kunit: skip test_kfree_rcu when the slub kunit test is built-in mm, slab: suppress warnings in test_leak_destroy kunit test rcu/kvfree: Refactor kvfree_rcu_queue_batch() mm, slab: fix use of SLAB_SUPPORTS_SYSFS in kmem_cache_release()
2024-10-04Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds
Pull close_range() fix from Al Viro: "Fix the logic in descriptor table trimming" * tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: close_range(): fix the logics in descriptor table trimming
2024-10-04prctl: arch-agnostic prctl for shadow stackMark Brown
Three architectures (x86, aarch64, riscv) have announced support for shadow stacks with fairly similar functionality. While x86 is using arch_prctl() to control the functionality neither arm64 nor riscv uses that interface so this patch adds arch-agnostic prctl() support to get and set status of shadow stacks and lock the current configuation to prevent further changes, with support for turning on and off individual subfeatures so applications can limit their exposure to features that they do not need. The features are: - PR_SHADOW_STACK_ENABLE: Tracking and enforcement of shadow stacks, including allocation of a shadow stack if one is not already allocated. - PR_SHADOW_STACK_WRITE: Writes to specific addresses in the shadow stack. - PR_SHADOW_STACK_PUSH: Push additional values onto the shadow stack. These features are expected to be inherited by new threads and cleared on exec(), unknown features should be rejected for enable but accepted for locking (in order to allow for future proofing). This is based on a patch originally written by Deepak Gupta but modified fairly heavily, support for indirect landing pads is removed, additional modes added and the locking interface reworked. The set status prctl() is also reworked to just set flags, if setting/reading the shadow stack pointer is required this could be a separate prctl. Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Yury Khrustalev <yury.khrustalev@arm.com> Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Deepak Gupta <debug@rivosinc.com> Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-4-222b78d87eee@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-03bpf: Use KF_FASTCALL to mark kfuncs supporting fastcall contractEduard Zingerman
In order to allow pahole add btf_decl_tag("bpf_fastcall") for kfuncs supporting bpf_fastcall, mark such functions with KF_FASTCALL in id_set8 objects. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240916091712.2929279-4-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-03bpf: Call kfree(obj) only once in free_one()Markus Elfring
A kfree() call is always used at the end of this function implementation. Thus specify such a function call only once instead of duplicating it in a previous if branch. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/08987123-668c-40f3-a8ee-c3038d94f069@web.de Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-03bpf: Constify struct btf_kind_operationsChristophe JAILLET
struct btf_kind_operations are not modified in BTF. Constifying this structures moves some data to a read-only section, so increase overall security, especially when the structure holds some function pointers. On a x86_64, with allmodconfig: Before: ====== text data bss dec hex filename 184320 7091 548 191959 2edd7 kernel/bpf/btf.o After: ===== text data bss dec hex filename 184896 6515 548 191959 2edd7 kernel/bpf/btf.o Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/9192ab72b2e9c66aefd6520f359a20297186327f.1726417289.git.christophe.jaillet@wanadoo.fr Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-10-03sched: psi: fix bogus pressure spikes from aggregation raceJohannes Weiner
Brandon reports sporadic, non-sensical spikes in cumulative pressure time (total=) when reading cpu.pressure at a high rate. This is due to a race condition between reader aggregation and tasks changing states. While it affects all states and all resources captured by PSI, in practice it most likely triggers with CPU pressure, since scheduling events are so frequent compared to other resource events. The race context is the live snooping of ongoing stalls during a pressure read. The read aggregates per-cpu records for stalls that have concluded, but will also incorporate ad-hoc the duration of any active state that hasn't been recorded yet. This is important to get timely measurements of ongoing stalls. Those ad-hoc samples are calculated on-the-fly up to the current time on that CPU; since the stall hasn't concluded, it's expected that this is the minimum amount of stall time that will enter the per-cpu records once it does. The problem is that the path that concludes the state uses a CPU clock read that is not synchronized against aggregators; the clock is read outside of the seqlock protection. This allows aggregators to race and snoop a stall with a longer duration than will actually be recorded. With the recorded stall time being less than the last snapshot remembered by the aggregator, a subsequent sample will underflow and observe a bogus delta value, resulting in an erratic jump in pressure. Fix this by moving the clock read of the state change into the seqlock protection. This ensures no aggregation can snoop live stalls past the time that's recorded when the state concludes. Reported-by: Brandon Duffany <brandon@buildbuddy.io> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219194 Link: https://lore.kernel.org/lkml/20240827121851.GB438928@cmpxchg.org/ Fixes: df77430639c9 ("psi: Reduce calls to sched_clock() in psi") Cc: stable@vger.kernel.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-10-03tracing/hwlat: Fix a race during cpuhp processingWei Li
The cpuhp online/offline processing race also exists in percpu-mode hwlat tracer in theory, apply the fix too. That is: T1 | T2 [CPUHP_ONLINE] | cpu_device_down() hwlat_hotplug_workfn() | | cpus_write_lock() | takedown_cpu(1) | cpus_write_unlock() [CPUHP_OFFLINE] | cpus_read_lock() | start_kthread(1) | cpus_read_unlock() | Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20240924094515.3561410-5-liwei391@huawei.com Fixes: ba998f7d9531 ("trace/hwlat: Support hotplug operations") Signed-off-by: Wei Li <liwei391@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03tracing/timerlat: Fix a race during cpuhp processingWei Li
There is another found exception that the "timerlat/1" thread was scheduled on CPU0, and lead to timer corruption finally: ``` ODEBUG: init active (active state 0) object: ffff888237c2e108 object type: hrtimer hint: timerlat_irq+0x0/0x220 WARNING: CPU: 0 PID: 426 at lib/debugobjects.c:518 debug_print_object+0x7d/0xb0 Modules linked in: CPU: 0 UID: 0 PID: 426 Comm: timerlat/1 Not tainted 6.11.0-rc7+ #45 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:debug_print_object+0x7d/0xb0 ... Call Trace: <TASK> ? __warn+0x7c/0x110 ? debug_print_object+0x7d/0xb0 ? report_bug+0xf1/0x1d0 ? prb_read_valid+0x17/0x20 ? handle_bug+0x3f/0x70 ? exc_invalid_op+0x13/0x60 ? asm_exc_invalid_op+0x16/0x20 ? debug_print_object+0x7d/0xb0 ? debug_print_object+0x7d/0xb0 ? __pfx_timerlat_irq+0x10/0x10 __debug_object_init+0x110/0x150 hrtimer_init+0x1d/0x60 timerlat_main+0xab/0x2d0 ? __pfx_timerlat_main+0x10/0x10 kthread+0xb7/0xe0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2d/0x40 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> ``` After tracing the scheduling event, it was discovered that the migration of the "timerlat/1" thread was performed during thread creation. Further analysis confirmed that it is because the CPU online processing for osnoise is implemented through workers, which is asynchronous with the offline processing. When the worker was scheduled to create a thread, the CPU may has already been removed from the cpu_online_mask during the offline process, resulting in the inability to select the right CPU: T1 | T2 [CPUHP_ONLINE] | cpu_device_down() osnoise_hotplug_workfn() | | cpus_write_lock() | takedown_cpu(1) | cpus_write_unlock() [CPUHP_OFFLINE] | cpus_read_lock() | start_kthread(1) | cpus_read_unlock() | To fix this, skip online processing if the CPU is already offline. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20240924094515.3561410-4-liwei391@huawei.com Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations") Signed-off-by: Wei Li <liwei391@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03tracing/timerlat: Drop interface_lock in stop_kthread()Wei Li
stop_kthread() is the offline callback for "trace/osnoise:online", since commit 5bfbcd1ee57b ("tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()"), the following ABBA deadlock scenario is introduced: T1 | T2 [BP] | T3 [AP] osnoise_hotplug_workfn() | work_for_cpu_fn() | cpuhp_thread_fun() | _cpu_down() | osnoise_cpu_die() mutex_lock(&interface_lock) | | stop_kthread() | cpus_write_lock() | mutex_lock(&interface_lock) cpus_read_lock() | cpuhp_kick_ap() | As the interface_lock here in just for protecting the "kthread" field of the osn_var, use xchg() instead to fix this issue. Also use for_each_online_cpu() back in stop_per_cpu_kthreads() as it can take cpu_read_lock() again. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20240924094515.3561410-3-liwei391@huawei.com Fixes: 5bfbcd1ee57b ("tracing/timerlat: Add interface_lock around clearing of kthread in stop_kthread()") Signed-off-by: Wei Li <liwei391@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03tracing/timerlat: Fix duplicated kthread creation due to CPU online/offlineWei Li
osnoise_hotplug_workfn() is the asynchronous online callback for "trace/osnoise:online". It may be congested when a CPU goes online and offline repeatedly and is invoked for multiple times after a certain online. This will lead to kthread leak and timer corruption. Add a check in start_kthread() to prevent this situation. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20240924094515.3561410-2-liwei391@huawei.com Fixes: c8895e271f79 ("trace/osnoise: Support hotplug operations") Signed-off-by: Wei Li <liwei391@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03tracing: Fix trace_check_vprintf() when tp_printk is usedSteven Rostedt
When the tp_printk kernel command line is used, the trace events go directly to printk(). It is still checked via the trace_check_vprintf() function to make sure the pointers of the trace event are legit. The addition of reading buffers from previous boots required adding a delta between the addresses of the previous boot and the current boot so that the pointers in the old buffer can still be used. But this required adding a trace_array pointer to acquire the delta offsets. The tp_printk code does not provide a trace_array (tr) pointer, so when the offsets were examined, a NULL pointer dereference happened and the kernel crashed. If the trace_array does not exist, just default the delta offsets to zero, as that also means the trace event is not being read from a previous boot. Link: https://lore.kernel.org/all/Zv3z5UsG_jsO9_Tb@aschofie-mobl2.lan/ Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20241003104925.4e1b1fd9@gandalf.local.home Fixes: 07714b4bb3f98 ("tracing: Handle old buffer mappings for event strings and functions") Reported-by: Alison Schofield <alison.schofield@intel.com> Tested-by: Alison Schofield <alison.schofield@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03audit: Reorganize kerneldoc parameter namesJulia Lawall
Reorganize kerneldoc parameter names to match the parameter order in the function header. Problems identified using Coccinelle. Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-10-03bpf: Include <linux/prandom.h> instead of <linux/random.h>Uros Bizjak
Substitute the inclusion of <linux/random.h> header with <linux/prandom.h> to allow the removal of legacy inclusion of <linux/prandom.h> from <linux/random.h>. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Eduard Zingerman <eddyz87@gmail.com> Cc: Song Liu <song@kernel.org> Cc: Yonghong Song <yonghong.song@linux.dev> Cc: KP Singh <kpsingh@kernel.org> Cc: Stanislav Fomichev <sdf@fomichev.me> Cc: Hao Luo <haoluo@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2024-10-02Merge tag 'pull-work.unaligned' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull generic unaligned.h cleanups from Al Viro: "Get rid of architecture-specific <asm/unaligned.h> includes, replacing them with a single generic <linux/unaligned.h> header file. It's the second largest (after asm/io.h) class of asm/* includes, and all but two architectures actually end up using exact same file. Massage the remaining two (arc and parisc) to do the same and just move the thing to from asm-generic/unaligned.h to linux/unaligned.h" [ This is one of those things that we're better off doing outside the merge window, and would only cause extra conflict noise if it was in linux-next for the next release due to all the trivial #include line updates. Rip off the band-aid. - Linus ] * tag 'pull-work.unaligned' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: move asm/unaligned.h to linux/unaligned.h arc: get rid of private asm/unaligned.h parisc: get rid of private asm/unaligned.h