Hello RT Folks! I'm pleased to announce the 5.4.182-rt71 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: v5.4-rt Head SHA1: 8f83fc7941f704f55939adaa778afd8ae76662e4 Or to build 5.4.182-rt71 directly, the following patches should be applied: https://www.kernel.org/pub/linux/kernel/v5.x/linux-5.4.tar.xz https://www.kernel.org/pub/linux/kernel/v5.x/patch-5.4.182.xz https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/patch-5.4.182-rt71.patch.xz You can also build from 5.4.182-rt70 by applying the incremental patch: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/incr/patch-5.4.182-rt70-rt71.patch.xz Enjoy! Tom Changes from v5.4.182-rt70: --- Thomas Gleixner (1): eventfd: Make signal recursion protection a task bit Tom Zanussi (1): Linux 5.4.182-rt71 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 | 12 ++++++++++++ localversion-rt | 2 +- 5 files changed, 24 insertions(+), 15 deletions(-) --- diff --git a/fs/aio.c b/fs/aio.c index fb92c32a6f1e..0bb9abf39065 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1767,7 +1767,7 @@ 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 78e41c7c3d05..661ccc45852b 100644 --- a/fs/eventfd.c +++ b/fs/eventfd.c @@ -24,8 +24,6 @@ #include <linux/seq_file.h> #include <linux/idr.h> -DEFINE_PER_CPU(int, eventfd_wake_count); - static DEFINE_IDA(eventfd_ida); struct eventfd_ctx { @@ -66,21 +64,21 @@ __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 dc4fd8a6644d..836b4c021a0a 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 79e34e98f812..e1dfb01f4623 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -802,6 +802,18 @@ struct task_struct { /* to be used once the psi infrastructure lands upstream. */ unsigned use_memdelay:1; #endif +#ifdef CONFIG_PSI + /* Stalled due to lack of memory */ + unsigned in_memstall:1; +#endif +#ifdef CONFIG_PAGE_OWNER + /* Used by page_owner=on to detect recursion in page tracking. */ + unsigned in_page_owner: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/localversion-rt b/localversion-rt index f36b5d418dd8..f38a3cc7f310 100644 --- a/localversion-rt +++ b/localversion-rt @@ -1 +1 @@ --rt70 +-rt71
