The patch titled Subject: genirq: reimplement exit_irq_thread() hook via task_work_add() has been added to the -mm tree. Its filename is genirq-reimplement-exit_irq_thread-hook-via-task_work_add.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: genirq: reimplement exit_irq_thread() hook via task_work_add() exit_irq_thread() and task->irq_thread are needed to handle the unexpected (and unlikely) exit of irq-thread. We can use task_work instead and make this all private to kernel/irq/manage.c, cleanup plus micro-optimization. 1. rename exit_irq_thread() to irq_thread_dtor(), make it static, and move it up before irq_thread(). 2. change irq_thread() to do task_work_add(irq_thread_dtor) at the start and task_work_cancel() before return. tracehook_notify_resume() can never play with kthreads, only do_exit()->exit_task_work() can call the callback and this is what we want. 3. remove task_struct->irq_thread and the special hook in do_exit(). Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: David Howells <dhowells@xxxxxxxxxx> Cc: Richard Kuo <rkuo@xxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Alexander Gordeev <agordeev@xxxxxxxxxx> Cc: Chris Zankel <chris@xxxxxxxxxx> Cc: David Smith <dsmith@xxxxxxxxxx> Cc: "Frank Ch. Eigler" <fche@xxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Larry Woodman <lwoodman@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/interrupt.h | 4 -- include/linux/sched.h | 10 +---- kernel/exit.c | 2 - kernel/irq/manage.c | 68 +++++++++++++++++------------------- 4 files changed, 35 insertions(+), 49 deletions(-) diff -puN include/linux/interrupt.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add include/linux/interrupt.h --- a/include/linux/interrupt.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add +++ a/include/linux/interrupt.h @@ -142,8 +142,6 @@ request_any_context_irq(unsigned int irq extern int __must_check request_percpu_irq(unsigned int irq, irq_handler_t handler, const char *devname, void __percpu *percpu_dev_id); - -extern void exit_irq_thread(void); #else extern int __must_check @@ -177,8 +175,6 @@ request_percpu_irq(unsigned int irq, irq { return request_irq(irq, handler, 0, devname, percpu_dev_id); } - -static inline void exit_irq_thread(void) { } #endif extern void free_irq(unsigned int, void *); diff -puN include/linux/sched.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add include/linux/sched.h --- a/include/linux/sched.h~genirq-reimplement-exit_irq_thread-hook-via-task_work_add +++ a/include/linux/sched.h @@ -1356,11 +1356,6 @@ struct task_struct { unsigned sched_reset_on_fork:1; unsigned sched_contributes_to_load:1; -#ifdef CONFIG_GENERIC_HARDIRQS - /* IRQ handler threads */ - unsigned irq_thread:1; -#endif - pid_t pid; pid_t tgid; @@ -1368,10 +1363,9 @@ struct task_struct { /* Canary value for the -fstack-protector gcc feature */ unsigned long stack_canary; #endif - - /* + /* * pointers to (original) parent process, youngest child, younger sibling, - * older sibling, respectively. (p->father can be replaced with + * older sibling, respectively. (p->father can be replaced with * p->real_parent->pid) */ struct task_struct __rcu *real_parent; /* real parent process */ diff -puN kernel/exit.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add kernel/exit.c --- a/kernel/exit.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add +++ a/kernel/exit.c @@ -954,8 +954,6 @@ void do_exit(long code) exit_task_work(tsk); - exit_irq_thread(); - if (unlikely(in_atomic())) printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", current->comm, task_pid_nr(current), diff -puN kernel/irq/manage.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add kernel/irq/manage.c --- a/kernel/irq/manage.c~genirq-reimplement-exit_irq_thread-hook-via-task_work_add +++ a/kernel/irq/manage.c @@ -14,6 +14,7 @@ #include <linux/interrupt.h> #include <linux/slab.h> #include <linux/sched.h> +#include <linux/task_work.h> #include "internals.h" @@ -773,11 +774,39 @@ static void wake_threads_waitq(struct ir wake_up(&desc->wait_for_threads); } +static void irq_thread_dtor(struct task_work *unused) +{ + struct task_struct *tsk = current; + struct irq_desc *desc; + struct irqaction *action; + + if (WARN_ON_ONCE(!(current->flags & PF_EXITING))) + return; + + action = kthread_data(tsk); + + pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n", + tsk->comm ? tsk->comm : "", tsk->pid, action->irq); + + + desc = irq_to_desc(action->irq); + /* + * If IRQTF_RUNTHREAD is set, we need to decrement + * desc->threads_active and wake possible waiters. + */ + if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) + wake_threads_waitq(desc); + + /* Prevent a stale desc->threads_oneshot */ + irq_finalize_oneshot(desc, action); +} + /* * Interrupt handler thread */ static int irq_thread(void *data) { + struct task_work on_exit_work; static const struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, }; @@ -793,7 +822,9 @@ static int irq_thread(void *data) handler_fn = irq_thread_fn; sched_setscheduler(current, SCHED_FIFO, ¶m); - current->irq_thread = 1; + + init_task_work(&on_exit_work, irq_thread_dtor, NULL); + task_work_add(current, &on_exit_work, false); while (!irq_wait_for_interrupt(action)) { irqreturn_t action_ret; @@ -815,44 +846,11 @@ static int irq_thread(void *data) * cannot touch the oneshot mask at this point anymore as * __setup_irq() might have given out currents thread_mask * again. - * - * Clear irq_thread. Otherwise exit_irq_thread() would make - * fuzz about an active irq thread going into nirvana. */ - current->irq_thread = 0; + task_work_cancel(current, irq_thread_dtor); return 0; } -/* - * Called from do_exit() - */ -void exit_irq_thread(void) -{ - struct task_struct *tsk = current; - struct irq_desc *desc; - struct irqaction *action; - - if (!tsk->irq_thread) - return; - - action = kthread_data(tsk); - - pr_err("genirq: exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n", - tsk->comm ? tsk->comm : "", tsk->pid, action->irq); - - desc = irq_to_desc(action->irq); - - /* - * If IRQTF_RUNTHREAD is set, we need to decrement - * desc->threads_active and wake possible waiters. - */ - if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) - wake_threads_waitq(desc); - - /* Prevent a stale desc->threads_oneshot */ - irq_finalize_oneshot(desc, action); -} - static void irq_setup_forced_threading(struct irqaction *new) { if (!force_irqthreads) _ Subject: Subject: genirq: reimplement exit_irq_thread() hook via task_work_add() Patches currently in -mm which might be from oleg@xxxxxxxxxx are linux-next.patch avr32-dont-mask-signals-in-the-error-path.patch avr32-use-set_current_blocked-in-handle_signal-sys_rt_sigreturn.patch avr32-use-block_sigmask.patch m32r-use-set_current_blocked-and-block_sigmask.patch m68k-use-set_current_blocked-and-block_sigmask.patch mn10300-use-set_current_blocked-and-block_sigmask.patch cris-use-set_current_blocked-and-block_sigmask.patch ia64-use-set_current_blocked-and-block_sigmask.patch microblaze-dont-reimplement-force_sigsegv.patch microblaze-no-need-to-reset-handler-if-sa_oneshot.patch microblaze-fix-signal-masking.patch microblaze-use-set_current_blocked-and-block_sigmask.patch score-dont-mask-signals-if-we-fail-to-setup-signal-stack.patch score-use-set_current_blocked-and-block_sigmask.patch h8300-use-set_current_blocked-and-block_sigmask.patch unicore32-use-block_sigmask.patch blackfin-use-set_current_blocked-and-block_sigmask.patch mm-fork-fix-overflow-in-vma-length-when-copying-mmap-on-clone.patch mm-correctly-synchronize-rss-counters-at-exit-exec.patch frv-use-set_current_blocked-and-block_sigmask.patch parisc-use-set_current_blocked-and-block_sigmask.patch task_work_add-generic-process-context-callbacks.patch genirq-reimplement-exit_irq_thread-hook-via-task_work_add.patch hexagon-do_notify_resume-needs-tracehook_notify_resume.patch keys-change-keyctl_session_to_parent-to-use-task_work_add.patch keys-kill-the-dummy-key_replace_session_keyring.patch keys-kill-task_struct-replacement_session_keyring.patch kmod-unexport-call_usermodehelper_freeinfo.patch kmod-convert-two-call-sites-to-call_usermodehelper_fns.patch kmod-move-call_usermodehelper_fns-to-c-file-and-unexport-all-its-helpers.patch cred-remove-task_is_dead-from-__task_cred-validation.patch stack-usage-add-pid-to-warning-printk-in-check_stack_usage.patch proc-clean-up-proc-pid-environ-handling.patch proc-unify-ptrace_may_access-locking-code.patch proc-remove-mm_for_maps.patch proc-use-mm_access-instead-of-ptrace_may_access.patch proc-use-is_err_or_null.patch fork-call-complete_vfork_done-after-clearing-child_tid-and-flushing-rss-counters.patch cpu-introduce-clear_tasks_mm_cpumask-helper.patch arm-use-clear_tasks_mm_cpumask.patch powerpc-use-clear_tasks_mm_cpumask.patch sh-use-clear_tasks_mm_cpumask.patch blackfin-a-couple-of-task-mm-handling-fixes.patch blackfin-fix-possible-deadlock-in-decode_address.patch um-should-hold-tasklist_lock-while-traversing-processes.patch um-fix-possible-race-on-task-mm.patch um-properly-check-all-process-threads-for-a-live-mm.patch aio-vfs-cleanup-of-rw_copy_check_uvector-and-compat_rw_copy_check_uvector.patch sysctl-make-kernelns_last_pid-control-being-checkpoint_restore-dependent.patch fs-proc-introduce-proc-pid-task-tid-children-entry-v9.patch fs-proc-introduce-proc-pid-task-tid-children-entry-v9-fix.patch c-r-prctl-add-ability-to-set-new-mm_struct-exe_file.patch c-r-prctl-add-ability-to-set-new-mm_struct-exe_file-update-after-mm-num_exe_file_vmas-removal.patch c-r-prctl-add-ability-to-get-clear_tid_address.patch c-r-prctl-drop-vma-flags-test-on-pr_set_mm_-stack-data-assignment.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html