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2022-06-22rcu-tasks: Be more patient for RCU Tasks boot-time testingPaul E. McKenney1-7/+21
The RCU-Tasks family of grace-period primitives can take some time to complete, and the amount of time can depend on the exact hardware and software configuration. Some configurations boot up fast enough that the RCU-Tasks verification process gets false-positive failures. This commit therefore allows up to 30 seconds for the grace periods to complete, with this value adjustable downwards using the rcupdate.rcu_task_stall_timeout kernel boot parameter. Reported-by: Matthew Wilcox <willy@infradead.org> Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Tested-by: Mark Rutland <mark.rutland@arm.com>
2022-06-22rcu-tasks: Update commentsPaul E. McKenney1-38/+33
This commit updates comments to reflect the changes in the series of commits that eliminated the full task-list scan. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-22rcu-tasks: Disable and enable CPU hotplug in same functionPaul E. McKenney1-3/+3
The rcu_tasks_trace_pregp_step() function invokes cpus_read_lock() to disable CPU hotplug, and a later call to the rcu_tasks_trace_postscan() function invokes cpus_read_unlock() to re-enable it. This was absolutely necessary in the past in order to protect the intervening scan of the full tasks list, but there is no longer such a scan. This commit therefore improves readability by moving the cpus_read_unlock() call to the end of the rcu_tasks_trace_pregp_step() function. This commit is a pure code-motion commit without any (intended) change in functionality. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-22rcu-tasks: Eliminate RCU Tasks Trace IPIs to online CPUsPaul E. McKenney3-17/+40
Currently, the RCU Tasks Trace grace-period kthread IPIs each online CPU using smp_call_function_single() in order to track any tasks currently in RCU Tasks Trace read-side critical sections during which the corresponding task has neither blocked nor been preempted. These IPIs are annoying and are also not strictly necessary because any task that blocks or is preempted within its current RCU Tasks Trace read-side critical section will be tracked on one of the per-CPU rcu_tasks_percpu structure's ->rtp_blkd_tasks list. So the only time that this is a problem is if one of the CPUs runs through a long-duration RCU Tasks Trace read-side critical section without a context switch. Note that the task_call_func() function cannot help here because there is no safe way to identify the target task. Of course, the task_call_func() function will be very useful later, when processing the list of tasks, but it needs to know the task. This commit therefore creates a cpu_curr_snapshot() function that returns a pointer the task_struct structure of some task that happened to be running on the specified CPU more or less during the time that the cpu_curr_snapshot() function was executing. If there was no context switch during this time, this function will return a pointer to the task_struct structure of the task that was running throughout. If there was a context switch, then the outgoing task will be taken care of by RCU's context-switch hook, and the incoming task was either already taken care during some previous context switch, or it is not currently within an RCU Tasks Trace read-side critical section. And in this latter case, the grace period already started, so there is no need to wait on this task. This new cpu_curr_snapshot() function is invoked on each CPU early in the RCU Tasks Trace grace-period processing, and the resulting tasks are queued for later quiescent-state inspection. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-22rcu-tasks: Maintain a count of tasks blocking RCU Tasks Trace grace periodPaul E. McKenney1-1/+5
This commit maintains a new n_trc_holdouts counter that tracks the number of tasks blocking the RCU Tasks grace period. This counter is useful for debugging, and its value has been added to a diagostic message. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-22rcu-tasks: Stop RCU Tasks Trace from scanning full tasks listPaul E. McKenney1-5/+6
This commit takes off the training wheels and relies only on scanning currently running tasks and tasks that have blocked or been preempted within their current RCU Tasks Trace read-side critical section. Before this commit, the time complexity of an RCU Tasks Trace grace period is O(T), where T is the number of tasks. After this commit, this time complexity is O(C+B), where C is the number of CPUs and B is the number of tasks that have blocked (or been preempted) at least once during their current RCU Tasks Trace read-side critical sections. Of course, if all tasks have blocked (or been preempted) at least once during their current RCU Tasks Trace read-side critical sections, this is still O(T), but current expectations are that RCU Tasks Trace read-side critical section will be short and that there will normally not be large numbers of tasks blocked within such a critical section. Dave Marchevsky kindly measured the effects of this commit on the RCU Tasks Trace grace-period latency and the rcu_tasks_trace_kthread task's CPU consumption per RCU Tasks Trace grace period over the course of a fixed test, all in milliseconds: Before After GP latency 22.3 ms stddev > 0.1 17.0 ms stddev < 0.1 GP CPU 2.3 ms stddev 0.3 1.1 ms stddev 0.2 This was on a system with 15,000 tasks, so it is reasonable to expect much larger savings on the systems on which this issue was first noted, given that they sport well in excess of 100,000 tasks. CPU consumption was measured using profiling techniques. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org> Tested-by: Dave Marchevsky <davemarchevsky@fb.com>
2022-06-20rcu-tasks: Stop RCU Tasks Trace from scanning idle tasksPaul E. McKenney1-7/+1
Now that RCU scans both running tasks and tasks that have blocked within their current RCU Tasks Trace read-side critical section, there is no need for it to scan the idle tasks. After all, an idle loop should not be remain within an RCU Tasks Trace read-side critical section across exit from idle, and from a BPF viewpoint, functions invoked from the idle loop should not sleep. So only running idle tasks can be within RCU Tasks Trace read-side critical sections. This commit therefore removes the scan of the idle tasks from the rcu_tasks_trace_postscan() function. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Pull in tasks blocked within RCU Tasks Trace readersPaul E. McKenney1-0/+24
This commit scans each CPU's ->rtp_blkd_tasks list, adding them to the list of holdout tasks. This will cause the current RCU Tasks Trace grace period to wait until these tasks exit their RCU Tasks Trace read-side critical sections. This commit will enable later work omitting the scan of the full task list. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Scan running tasks for RCU Tasks Trace readersPaul E. McKenney1-11/+40
A running task might be within an RCU Tasks Trace read-side critical section for any length of time, but will not be placed on any of the per-CPU rcu_tasks_percpu structure's ->rtp_blkd_tasks lists. Therefore any RCU Tasks Trace grace-period processing that does not scan the full task list must interact with the running tasks. This commit therefore causes the rcu_tasks_trace_pregp_step() function to IPI each CPU in order to place the corresponding task on the holdouts list and to record whether or not it was in an RCU Tasks Trace read-side critical section. Yes, it is possible to avoid adding it to that list if it is not a reader, but that would prevent the system from remembering that this task was in a quiescent state. Which is why the running tasks are unconditionally added to the holdout list. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Avoid rcu_tasks_trace_pertask() duplicate list additionsPaul E. McKenney1-3/+4
This commit adds checks within rcu_tasks_trace_pertask() to avoid duplicate (and destructive) additions to the holdouts list. These checks will be required later due to the possibility of a given task having blocked while in an RCU Tasks Trace read-side critical section, but now running on a CPU. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Move rcu_tasks_trace_pertask() before rcu_tasks_trace_pregp_step()Paul E. McKenney1-14/+14
This is a code-motion-only commit that moves rcu_tasks_trace_pertask() to precede rcu_tasks_trace_pregp_step(), so that the latter will be able to invoke the other without forward references. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Add blocked-task indicator to RCU Tasks Trace stall warningsPaul E. McKenney1-1/+2
This commit adds a "B" indicator to the RCU Tasks Trace CPU stall warning when the task has blocked within its current read-side critical section. This serves as a debugging aid. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Untrack blocked RCU Tasks Trace at reader endPaul E. McKenney1-6/+18
This commit causes rcu_read_unlock_trace() to check for the current task being on a per-CPU list within the rcu_tasks_percpu structure, and removes it from that list if so. This has the effect of curtailing tracking of a task that blocked within an RCU Tasks Trace read-side critical section once it exits that critical section. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Track blocked RCU Tasks Trace readersPaul E. McKenney3-4/+31
This commit places any task that has ever blocked within its current RCU Tasks Trace read-side critical section on a per-CPU list within the rcu_tasks_percpu structure. Tasks are removed from this list when they exit by the exit_tasks_rcu_finish_trace() function. The purpose of this commit is to provide the information needed to eliminate the current scan of the full task list. This commit offsets the INT_MIN value for ->trc_reader_nesting with the new nesting level in order to avoid queueing tasks that are exiting their read-side critical sections. [ paulmck: Apply kernel test robot feedback. ] [ paulmck: Apply feedback from syzbot+9bb26e7c5e8e4fa7e641@syzkaller.appspotmail.com ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: syzbot <syzbot+9bb26e7c5e8e4fa7e641@syzkaller.appspotmail.com> Tested-by: "Zhang, Qiang1" <qiang1.zhang@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Add data structures for lightweight grace periodsPaul E. McKenney4-0/+8
This commit adds fields to task_struct and to rcu_tasks_percpu that will be used to avoid the task-list scan for RCU Tasks Trace grace periods, and also initializes these fields. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Make RCU Tasks Trace stall warning handle idle offline tasksPaul E. McKenney1-1/+1
When a CPU is offline, its idle task can appear to be running, but it cannot be doing anything while CPU-hotplug operations are excluded. This commit takes advantage of that fact by making trc_check_slow_task() check for task_curr(t) && cpu_online(task_cpu(t)), and recording full information in that case. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Make RCU Tasks Trace stall warnings print full .b.need_qs fieldPaul E. McKenney1-2/+3
Currently, the RCU Tasks Trace CPU stall warning simply indicates whether or not the .b.need_qs field is zero. This commit shows the three permitted values and flags other values with either "!" or "?". This is a debugging aid. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Flag offline CPUs in RCU Tasks Trace stall warningsPaul E. McKenney1-2/+2
This commit tags offline CPUs with "(offline)" in RCU Tasks Trace CPU stall warnings. This is a debugging aid. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Add slow-IPI indicator to RCU Tasks Trace stall warningsPaul E. McKenney1-1/+2
This commit adds a "I" indicator to the RCU Tasks Trace CPU stall warning when an IPI directed to a task has thus far failed to arrive. This serves as a debugging aid. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Simplify trc_inspect_reader() QS logicPaul E. McKenney1-6/+7
Currently, trc_inspect_reader() does one check for nesting less than or equal to zero, then sorts out the distinctions within this single "if" statement. This commit simplifies the logic by providing one "if" statement for quiescent states (nesting of zero) and another "if" statement for transitioning from one nesting level to another or the outermost rcu_read_unlock_trace() (negative nesting). Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Make rcu_note_context_switch() unconditionally call rcu_tasks_qs()Paul E. McKenney1-1/+1
This commit makes rcu_note_context_switch() unconditionally invoke the rcu_tasks_qs() function, as opposed to doing so only when RCU (as opposed to RCU Tasks Trace) urgently needs a grace period to end. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: RCU Tasks Trace grace-period kthread has implicit QSPaul E. McKenney1-2/+3
Because the task driving the grace-period kthread is in quiescent state throughout, this commit excludes it from the list of tasks from which a quiescent state is needed. This does mean that attaching a sleepable BPF program to function in kernel/rcu/tasks.h is a bad idea, by the way. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Handle idle tasks for recently offlined CPUsPaul E. McKenney1-8/+7
This commit identifies idle tasks for recently offlined CPUs as residing in a quiescent state. This is safe only because CPU-hotplug operations are excluded during these checks. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Idle tasks on offline CPUs are in quiescent statesPaul E. McKenney1-1/+1
Any idle task corresponding to an offline CPU is in an RCU Tasks Trace quiescent state. This commit causes rcu_tasks_trace_postscan() to ignore idle tasks for offline CPUs, which it can do safely due to CPU-hotplug operations being disabled. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Make trc_read_check_handler() fetch ->trc_reader_nesting only oncePaul E. McKenney1-2/+4
This commit replaces the pair of READ_ONCE(t->trc_reader_nesting) calls with a single such call and a local variable. This makes the code's intent more clear. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Remove rcu_tasks_trace_postgp() wait for counterPaul E. McKenney1-59/+3
Now that tasks are not removed from the list until they have responded to any needed request for a quiescent state, it is no longer necessary to wait for the trc_n_readers_need_end counter to go to zero. This commit therefore removes that waiting code. It is therefore also no longer necessary for rcu_tasks_trace_postgp() to do the final decrement of this counter, so that code is also removed. This in turn means that trc_n_readers_need_end counter itself can be removed, as can the rcu_tasks_trace_iw irq_work structure and the rcu_read_unlock_iw() function. [ paulmck: Apply feedback from Zqiang. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Merge state into .b.need_qs and atomically updatePaul E. McKenney3-40/+82
This commit gets rid of the task_struct structure's ->trc_reader_checked field, making it instead be a bit within the task_struct structure's existing ->trc_reader_special.b.need_qs field. This commit also atomically loads, stores, and checks the resulting combination of the reader-checked and need-quiescent state flags. This will in turn allow significant simplification of the rcu_tasks_trace_postgp() function as well as elimination of the trc_n_readers_need_end counter in later commits. These changes will in turn simplify later elimination of the RCU Tasks Trace scan of the task list, which will make RCU Tasks Trace grace periods less CPU-intensive. [ paulmck: Apply kernel test robot feedback. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Martin KaFai Lau <kafai@fb.com> Cc: KP Singh <kpsingh@kernel.org>
2022-06-20rcu-tasks: Drive synchronous grace periods from calling taskPaul E. McKenney1-8/+16
This commit causes synchronous grace periods to be driven from the task invoking synchronize_rcu_*(), allowing these functions to be invoked from the mid-boot dead zone extending from when the scheduler was initialized to to point that the various RCU tasks grace-period kthreads are spawned. This change will allow the self-tests to run in a consistent manner. Reported-by: Matthew Wilcox <willy@infradead.org> Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-06-20rcu-tasks: Move synchronize_rcu_tasks_generic() downPaul E. McKenney1-11/+11
This is strictly a code-motion commit that moves the synchronize_rcu_tasks_generic() down to where it can invoke rcu_tasks_one_gp() without the need for a forward declaration. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-06-20rcu-tasks: Split rcu_tasks_one_gp() from rcu_tasks_kthread()Paul E. McKenney1-22/+36
This commit abstracts most of the rcu_tasks_kthread() function's loop body into a new rcu_tasks_one_gp() function. It also introduces a new ->tasks_gp_mutex to synchronize concurrent calls to this new rcu_tasks_one_gp() function. This commit is preparation for allowing RCU tasks grace periods to be driven by the calling task during the mid-boot dead zone. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-06-20rcu-tasks: Check for abandoned callbacksPaul E. McKenney1-0/+5
This commit adds a debugging scan for callbacks that got lost during a callback-queueing transition. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-06-19Linux 5.19-rc3v5.19-rc3Linus Torvalds1-1/+1
2022-06-19Merge tag 'x86-urgent-2022-06-19' of ↵Linus Torvalds4-75/+159
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: - Make RESERVE_BRK() work again with older binutils. The recent 'simplification' broke that. - Make early #VE handling increment RIP when successful. - Make the #VE code consistent vs. the RIP adjustments and add comments. - Handle load_unaligned_zeropad() across page boundaries correctly in #VE when the second page is shared. * tag 'x86-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tdx: Handle load_unaligned_zeropad() page-cross to a shared page x86/tdx: Clarify RIP adjustments in #VE handler x86/tdx: Fix early #VE handling x86/mm: Fix RESERVE_BRK() for older binutils
2022-06-19Merge tag 'objtool-urgent-2022-06-19' of ↵Linus Torvalds6-19/+55
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull build tooling updates from Thomas Gleixner: - Remove obsolete CONFIG_X86_SMAP reference from objtool - Fix overlapping text section failures in faddr2line for real - Remove OBJECT_FILES_NON_STANDARD usage from x86 ftrace and replace it with finegrained annotations so objtool can validate that code correctly. * tag 'objtool-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/ftrace: Remove OBJECT_FILES_NON_STANDARD usage faddr2line: Fix overlapping text section failures, the sequel objtool: Fix obsolete reference to CONFIG_X86_SMAP
2022-06-19Merge tag 'sched-urgent-2022-06-19' of ↵Linus Torvalds2-3/+38
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fix from Thomas Gleixner: "A single scheduler fix plugging a race between sched_setscheduler() and balance_push(). sched_setscheduler() spliced the balance callbacks accross a lock break which makes it possible for an interleaving schedule() to observe an empty list" * tag 'sched-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Fix balance_push() vs __sched_setscheduler()
2022-06-19Merge tag 'locking-urgent-2022-06-19' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull lockdep fix from Thomas Gleixner: "A RT fix for lockdep. lockdep invokes prandom_u32() to create cookies. This worked until prandom_u32() was switched to the real random generator, which takes a spinlock for extraction, which does not work on RT when invoked from atomic contexts. lockdep has no requirement for real random numbers and it turns out sched_clock() is good enough to create the cookie. That works everywhere and is faster" * tag 'locking-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/lockdep: Use sched_clock() for random numbers
2022-06-19Merge tag 'irq-urgent-2022-06-19' of ↵Linus Torvalds9-6/+23
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: "A set of interrupt subsystem updates: Core: - Ensure runtime power management for chained interrupts Drivers: - A collection of OF node refcount fixes - Unbreak MIPS uniprocessor builds - Fix xilinx interrupt controller Kconfig dependencies - Add a missing compatible string to the Uniphier driver" * tag 'irq-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/loongson-liointc: Use architecture register to get coreid irqchip/uniphier-aidet: Add compatible string for NX1 SoC dt-bindings: interrupt-controller/uniphier-aidet: Add bindings for NX1 SoC irqchip/realtek-rtl: Fix refcount leak in map_interrupts irqchip/gic-v3: Fix refcount leak in gic_populate_ppi_partitions irqchip/gic-v3: Fix error handling in gic_populate_ppi_partitions irqchip/apple-aic: Fix refcount leak in aic_of_ic_init irqchip/apple-aic: Fix refcount leak in build_fiq_affinity irqchip/gic/realview: Fix refcount leak in realview_gic_of_init irqchip/xilinx: Remove microblaze+zynq dependency genirq: PM: Use runtime PM for chained interrupts
2022-06-19Merge tag 'char-misc-5.19-rc3-take2' of ↵Linus Torvalds7-5/+14
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver fixes for real from Greg KH: "Let's tag the proper branch this time... Here are some small char/misc driver fixes for 5.19-rc3 that resolve some reported issues. They include: - mei driver fixes - comedi driver fix - rtsx build warning fix - fsl-mc-bus driver fix All of these have been in linux-next for a while with no reported issues" This is what the merge in commit f0ec9c65a8d6 _should_ have merged, but Greg fat-fingered the pull request and I got some small changes from linux-next instead there. Credit to Nathan Chancellor for eagle-eyes. Link: https://lore.kernel.org/all/Yqywy+Md2AfGDu8v@dev-arch.thelio-3990X/ * tag 'char-misc-5.19-rc3-take2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: bus: fsl-mc-bus: fix KASAN use-after-free in fsl_mc_bus_remove() mei: me: add raptor lake point S DID mei: hbm: drop capability response on early shutdown mei: me: set internal pg flag to off on hardware reset misc: rtsx: Fix clang -Wsometimes-uninitialized in rts5261_init_from_hw() comedi: vmk80xx: fix expression for tx buffer size
2022-06-19Merge tag 'i2c-for-5.19-rc3' of ↵Linus Torvalds5-10/+22
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux Pull i2c fixes from Wolfram Sang: "MAINTAINERS rectifications and a few minor driver fixes" * tag 'i2c-for-5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: i2c: mediatek: Fix an error handling path in mtk_i2c_probe() i2c: designware: Use standard optional ref clock implementation MAINTAINERS: core DT include belongs to core MAINTAINERS: add include/dt-bindings/i2c to I2C SUBSYSTEM HOST DRIVERS i2c: npcm7xx: Add check for platform_driver_register MAINTAINERS: Update Synopsys DesignWare I2C to Supported
2022-06-19Merge tag 'xfs-5.19-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds7-25/+37
Pull xfs fixes from Darrick Wong: "There's not a whole lot this time around (I'm still on vacation) but here are some important fixes for new features merged in -rc1: - Fix a bug where inode flag changes would accidentally drop nrext64 - Fix a race condition when toggling LARP mode" * tag 'xfs-5.19-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: preserve DIFLAG2_NREXT64 when setting other inode attributes xfs: fix variable state usage xfs: fix TOCTOU race involving the new logged xattrs control knob
2022-06-19Merge tag 'ext4_for_linus_stable' of ↵Linus Torvalds26-895/+947
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 fixes from Ted Ts'o: "Fix a variety of bugs, many of which were found by folks using fuzzing or error injection. Also fix up how test_dummy_encryption mount option is handled for the new mount API. Finally, fix/cleanup a number of comments and ext4 Documentation files" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix a doubled word "need" in a comment ext4: add reserved GDT blocks check ext4: make variable "count" signed ext4: correct the judgment of BUG in ext4_mb_normalize_request ext4: fix bug_on ext4_mb_use_inode_pa ext4: fix up test_dummy_encryption handling for new mount API ext4: use kmemdup() to replace kmalloc + memcpy ext4: fix super block checksum incorrect after mount ext4: improve write performance with disabled delalloc ext4: fix warning when submitting superblock in ext4_commit_super() ext4, doc: remove unnecessary escaping ext4: fix incorrect comment in ext4_bio_write_page() fs: fix jbd2_journal_try_to_free_buffers() kernel-doc comment
2022-06-19Merge tag '5.19-rc2-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds3-0/+43
Pull cifs client fixes from Steve French: "Two cifs debugging improvements - one found to deal with debugging a multichannel problem and one for a recent fallocate issue This does include the two larger multichannel reconnect (dynamically adjusting interfaces on reconnect) patches, because we recently found an additional problem with multichannel to one server type that I want to include at the same time" * tag '5.19-rc2-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: when a channel is not found for server, log its connection id smb3: add trace point for SMB2_set_eof
2022-06-19ext4: fix a doubled word "need" in a commentXiang wangx1-1/+1
Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com> Link: https://lore.kernel.org/r/20220605091503.12513-1-wangxiang@cdjrlc.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: add reserved GDT blocks checkZhang Yi1-0/+10
We capture a NULL pointer issue when resizing a corrupt ext4 image which is freshly clear resize_inode feature (not run e2fsck). It could be simply reproduced by following steps. The problem is because of the resize_inode feature was cleared, and it will convert the filesystem to meta_bg mode in ext4_resize_fs(), but the es->s_reserved_gdt_blocks was not reduced to zero, so could we mistakenly call reserve_backup_gdb() and passing an uninitialized resize_inode to it when adding new group descriptors. mkfs.ext4 /dev/sda 3G tune2fs -O ^resize_inode /dev/sda #forget to run requested e2fsck mount /dev/sda /mnt resize2fs /dev/sda 8G ======== BUG: kernel NULL pointer dereference, address: 0000000000000028 CPU: 19 PID: 3243 Comm: resize2fs Not tainted 5.18.0-rc7-00001-gfde086c5ebfd #748 ... RIP: 0010:ext4_flex_group_add+0xe08/0x2570 ... Call Trace: <TASK> ext4_resize_fs+0xbec/0x1660 __ext4_ioctl+0x1749/0x24e0 ext4_ioctl+0x12/0x20 __x64_sys_ioctl+0xa6/0x110 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2dd739617b ======== The fix is simple, add a check in ext4_resize_begin() to make sure that the es->s_reserved_gdt_blocks is zero when the resize_inode feature is disabled. Cc: stable@kernel.org Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20220601092717.763694-1-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: make variable "count" signedDing Xiang1-1/+2
Since dx_make_map() may return -EFSCORRUPTED now, so change "count" to be a signed integer so we can correctly check for an error code returned by dx_make_map(). Fixes: 46c116b920eb ("ext4: verify dir block before splitting it") Cc: stable@kernel.org Signed-off-by: Ding Xiang <dingxiang@cmss.chinamobile.com> Link: https://lore.kernel.org/r/20220530100047.537598-1-dingxiang@cmss.chinamobile.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: correct the judgment of BUG in ext4_mb_normalize_requestBaokun Li1-1/+16
ext4_mb_normalize_request() can move logical start of allocated blocks to reduce fragmentation and better utilize preallocation. However logical block requested as a start of allocation (ac->ac_o_ex.fe_logical) should always be covered by allocated blocks so we should check that by modifying and to or in the assertion. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20220528110017.354175-3-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: fix bug_on ext4_mb_use_inode_paBaokun Li1-0/+9
Hulk Robot reported a BUG_ON: ================================================================== kernel BUG at fs/ext4/mballoc.c:3211! [...] RIP: 0010:ext4_mb_mark_diskspace_used.cold+0x85/0x136f [...] Call Trace: ext4_mb_new_blocks+0x9df/0x5d30 ext4_ext_map_blocks+0x1803/0x4d80 ext4_map_blocks+0x3a4/0x1a10 ext4_writepages+0x126d/0x2c30 do_writepages+0x7f/0x1b0 __filemap_fdatawrite_range+0x285/0x3b0 file_write_and_wait_range+0xb1/0x140 ext4_sync_file+0x1aa/0xca0 vfs_fsync_range+0xfb/0x260 do_fsync+0x48/0xa0 [...] ================================================================== Above issue may happen as follows: ------------------------------------- do_fsync vfs_fsync_range ext4_sync_file file_write_and_wait_range __filemap_fdatawrite_range do_writepages ext4_writepages mpage_map_and_submit_extent mpage_map_one_extent ext4_map_blocks ext4_mb_new_blocks ext4_mb_normalize_request >>> start + size <= ac->ac_o_ex.fe_logical ext4_mb_regular_allocator ext4_mb_simple_scan_group ext4_mb_use_best_found ext4_mb_new_preallocation ext4_mb_new_inode_pa ext4_mb_use_inode_pa >>> set ac->ac_b_ex.fe_len <= 0 ext4_mb_mark_diskspace_used >>> BUG_ON(ac->ac_b_ex.fe_len <= 0); we can easily reproduce this problem with the following commands: `fallocate -l100M disk` `mkfs.ext4 -b 1024 -g 256 disk` `mount disk /mnt` `fsstress -d /mnt -l 0 -n 1000 -p 1` The size must be smaller than or equal to EXT4_BLOCKS_PER_GROUP. Therefore, "start + size <= ac->ac_o_ex.fe_logical" may occur when the size is truncated. So start should be the start position of the group where ac_o_ex.fe_logical is located after alignment. In addition, when the value of fe_logical or EXT4_BLOCKS_PER_GROUP is very large, the value calculated by start_off is more accurate. Cc: stable@kernel.org Fixes: cd648b8a8fd5 ("ext4: trim allocation requests to group size") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20220528110017.354175-2-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: fix up test_dummy_encryption handling for new mount APIEric Biggers1-63/+71
Since ext4 was converted to the new mount API, the test_dummy_encryption mount option isn't being handled entirely correctly, because the needed fscrypt_set_test_dummy_encryption() helper function combines parsing/checking/applying into one function. That doesn't work well with the new mount API, which split these into separate steps. This was sort of okay anyway, due to the parsing logic that was copied from fscrypt_set_test_dummy_encryption() into ext4_parse_param(), combined with an additional check in ext4_check_test_dummy_encryption(). However, these overlooked the case of changing the value of test_dummy_encryption on remount, which isn't allowed but ext4 wasn't detecting until ext4_apply_options() when it's too late to fail. Another bug is that if test_dummy_encryption was specified multiple times with an argument, memory was leaked. Fix this up properly by using the new helper functions that allow splitting up the parse/check/apply steps for test_dummy_encryption. Fixes: cebe85d570cf ("ext4: switch to the new mount api") Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20220526040412.173025-1-ebiggers@kernel.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: use kmemdup() to replace kmalloc + memcpyShuqi Zhang1-2/+1
Replace kmalloc + memcpy with kmemdup() Signed-off-by: Shuqi Zhang <zhangshuqi3@huawei.com> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20220525030120.803330-1-zhangshuqi3@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-06-19ext4: fix super block checksum incorrect after mountYe Bin1-8/+8
We got issue as follows: [home]# mount /dev/sda test EXT4-fs (sda): warning: mounting fs with errors, running e2fsck is recommended [home]# dmesg EXT4-fs (sda): warning: mounting fs with errors, running e2fsck is recommended EXT4-fs (sda): Errors on filesystem, clearing orphan list. EXT4-fs (sda): recovery complete EXT4-fs (sda): mounted filesystem with ordered data mode. Quota mode: none. [home]# debugfs /dev/sda debugfs 1.46.5 (30-Dec-2021) Checksum errors in superblock! Retrying... Reason is ext4_orphan_cleanup will reset ‘s_last_orphan’ but not update super block checksum. To solve above issue, defer update super block checksum after ext4_orphan_cleanup. Signed-off-by: Ye Bin <yebin10@huawei.com> Cc: stable@kernel.org Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com> Link: https://lore.kernel.org/r/20220525012904.1604737-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>