Hello RT-list! I'm pleased to announce the 5.10.90-rt61 stable release. You can get this release via the git tree at: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git branch: v5.10-rt Head SHA1: 8bff2d3a6cbc31ef22f1f24ec4f76ddb48892503 Or to build 5.10.90-rt61 directly, the following patches should be applied: https://www.kernel.org/pub/linux/kernel/v5.x/linux-5.10.tar.xz https://www.kernel.org/pub/linux/kernel/v5.x/patch-5.10.90.xz https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/patch-5.10.90-rt61.patch.xz All keys used for the uploads can be found on the following git repository: git://git.kernel.org/pub/scm/docs/kernel/pgpkeys.git Enjoy! Luis Changes from v5.10.90-rt60: --- Luis Claudio R. Goncalves (1): Linux 5.10.90-rt61 Sebastian Andrzej Siewior (1): stop_machine: Remove this_cpu_ptr() from print_stop_info(). Thomas Gleixner (1): eventfd: Make signal recursion protection a task bit Xie Yongji (1): aio: Fix incorrect usage of eventfd_signal_allowed() --- fs/aio.c | 2 +- fs/eventfd.c | 12 +++++------- include/linux/eventfd.h | 11 +++++------ include/linux/sched.h | 4 ++++ kernel/stop_machine.c | 6 +++++- localversion-rt | 2 +- 6 files changed, 21 insertions(+), 16 deletions(-) --- diff --git a/fs/aio.c b/fs/aio.c index c72b2c51b446c..1a78979663dca 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1761,7 +1761,7 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, list_del_init(&req->wait.entry); list_del(&iocb->ki_list); iocb->ki_res.res = mangle_poll(mask); - if (iocb->ki_eventfd && eventfd_signal_count()) { + if (iocb->ki_eventfd && !eventfd_signal_allowed()) { iocb = NULL; INIT_WORK(&req->work, aio_poll_put_work); schedule_work(&req->work); diff --git a/fs/eventfd.c b/fs/eventfd.c index df466ef81dddf..9035ca60bfcf3 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -25,8 +25,6 @@ #include <linux/idr.h> #include <linux/uio.h> -DEFINE_PER_CPU(int, eventfd_wake_count); - static DEFINE_IDA(eventfd_ida); struct eventfd_ctx { @@ -67,21 +65,21 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n) * Deadlock or stack overflow issues can happen if we recurse here * through waitqueue wakeup handlers. If the caller users potentially * nested waitqueues with custom wakeup handlers, then it should - * check eventfd_signal_count() before calling this function. If - * it returns true, the eventfd_signal() call should be deferred to a + * check eventfd_signal_allowed() before calling this function. If + * it returns false, the eventfd_signal() call should be deferred to a * safe context. */ - if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count))) + if (WARN_ON_ONCE(current->in_eventfd_signal)) return 0; spin_lock_irqsave(&ctx->wqh.lock, flags); - this_cpu_inc(eventfd_wake_count); + current->in_eventfd_signal = 1; if (ULLONG_MAX - ctx->count < n) n = ULLONG_MAX - ctx->count; ctx->count += n; if (waitqueue_active(&ctx->wqh)) wake_up_locked_poll(&ctx->wqh, EPOLLIN); - this_cpu_dec(eventfd_wake_count); + current->in_eventfd_signal = 0; spin_unlock_irqrestore(&ctx->wqh.lock, flags); return n; diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index dc4fd8a6644dd..836b4c021a0a4 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -14,6 +14,7 @@ #include <linux/err.h> #include <linux/percpu-defs.h> #include <linux/percpu.h> +#include <linux/sched.h> /* * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining @@ -42,11 +43,9 @@ __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, __u64 *cnt); -DECLARE_PER_CPU(int, eventfd_wake_count); - -static inline bool eventfd_signal_count(void) +static inline bool eventfd_signal_allowed(void) { - return this_cpu_read(eventfd_wake_count); + return !current->in_eventfd_signal; } #else /* CONFIG_EVENTFD */ @@ -77,9 +76,9 @@ static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, return -ENOSYS; } -static inline bool eventfd_signal_count(void) +static inline bool eventfd_signal_allowed(void) { - return false; + return true; } #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 409a24036952c..29e6ff1af1df9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -852,6 +852,10 @@ struct task_struct { /* Stalled due to lack of memory */ unsigned in_memstall:1; #endif +#ifdef CONFIG_EVENTFD + /* Recursion prevention for eventfd_signal() */ + unsigned in_eventfd_signal:1; +#endif unsigned long atomic_flags; /* Flags requiring atomic access. */ diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index dbf585cf4b9f8..971d8acceaecb 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -51,7 +51,11 @@ static bool stop_machine_initialized = false; void print_stop_info(const char *log_lvl, struct task_struct *task) { - struct cpu_stopper *stopper = this_cpu_ptr(&cpu_stopper); + /* + * If @task is a stopper task, it cannot migrate and task_cpu() is + * stable. + */ + struct cpu_stopper *stopper = per_cpu_ptr(&cpu_stopper, task_cpu(task)); if (task != stopper->thread) return; diff --git a/localversion-rt b/localversion-rt index 66fa05e70f292..9b7de9345ef4c 100644 --- a/localversion-rt +++ b/localversion-rt @@ -1 +1 @@ --rt60 +-rt61
