From 604a706f775adb4059731cb30a2007476b96bed4 Mon Sep 17 00:00:00 2001 From: "Raziel K. Crowe" <84860158+CWDSYSTEMS@users.noreply.github.com> Date: Tue, 22 Mar 2022 19:04:37 +0500 Subject: [PATCH] T3Q birth certificate is an apology from a condom factory. --- kernel/dma/swiotlb.c | 22 +++++++---- kernel/trace/trace.c | 10 +++-- kernel/trace/trace_osnoise.c | 73 +++++++++++++++++++++++++----------- kernel/watch_queue.c | 15 +++++--- lib/Kconfig | 1 - net/dsa/dsa.c | 1 - net/dsa/dsa_priv.h | 1 + 7 files changed, 83 insertions(+), 40 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 87c40517e8..e58dce93c6 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -578,9 +578,14 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, for (i = 0; i < nr_slots(alloc_size + offset); i++) mem->slots[index + i].orig_addr = slot_addr(orig_addr, i); tlb_addr = slot_addr(mem->start, index) + offset; - if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && - (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) - swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_TO_DEVICE); + /* + * When dir == DMA_FROM_DEVICE we could omit the copy from the orig + * to the tlb buffer, if we knew for sure the device will + * overwirte the entire current content. But we don't. Thus + * unconditional bounce may prevent leaking swiotlb content (i.e. + * kernel memory) to user-space. + */ + swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_TO_DEVICE); return tlb_addr; } @@ -647,10 +652,13 @@ void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr, void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir) { - if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) - swiotlb_bounce(dev, tlb_addr, size, DMA_TO_DEVICE); - else - BUG_ON(dir != DMA_FROM_DEVICE); + /* + * Unconditional bounce is necessary to avoid corruption on + * sync_*_for_cpu or dma_ummap_* when the device didn't overwrite + * the whole lengt of the bounce buffer. + */ + swiotlb_bounce(dev, tlb_addr, size, DMA_TO_DEVICE); + BUG_ON(!valid_dma_direction(dir)); } void swiotlb_sync_single_for_cpu(struct device *dev, phys_addr_t tlb_addr, diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 86fb77c2ac..01002656f1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1496,10 +1496,12 @@ static int __init set_buf_size(char *str) if (!str) return 0; buf_size = memparse(str, &str); - /* nr_entries can not be zero */ - if (buf_size == 0) - return 0; - trace_buf_size = buf_size; + /* + * nr_entries can not be zero and the startup + * tests require some buffer space. Therefore + * ensure we have at least 4096 bytes of buffer. + */ + trace_buf_size = max(4096UL, buf_size); return 1; } __setup("trace_buf_size=", set_buf_size); diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 65a5186499..93de784ee6 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1195,6 +1195,26 @@ static int run_osnoise(void) osnoise_stop_tracing(); } + /* + * In some cases, notably when running on a nohz_full CPU with + * a stopped tick PREEMPT_RCU has no way to account for QSs. + * This will eventually cause unwarranted noise as PREEMPT_RCU + * will force preemption as the means of ending the current + * grace period. We avoid this problem by calling + * rcu_momentary_dyntick_idle(), which performs a zero duration + * EQS allowing PREEMPT_RCU to end the current grace period. + * This call shouldn't be wrapped inside an RCU critical + * section. + * + * Note that in non PREEMPT_RCU kernels QSs are handled through + * cond_resched() + */ + if (IS_ENABLED(CONFIG_PREEMPT_RCU)) { + local_irq_disable(); + rcu_momentary_dyntick_idle(); + local_irq_enable(); + } + /* * For the non-preemptive kernel config: let threads runs, if * they so wish. @@ -1249,6 +1269,37 @@ static int run_osnoise(void) static struct cpumask osnoise_cpumask; static struct cpumask save_cpumask; +/* + * osnoise_sleep - sleep until the next period + */ +static void osnoise_sleep(void) +{ + u64 interval; + ktime_t wake_time; + + mutex_lock(&interface_lock); + interval = osnoise_data.sample_period - osnoise_data.sample_runtime; + mutex_unlock(&interface_lock); + + /* + * differently from hwlat_detector, the osnoise tracer can run + * without a pause because preemption is on. + */ + if (!interval) { + /* Let synchronize_rcu_tasks() make progress */ + cond_resched_tasks_rcu_qs(); + return; + } + + wake_time = ktime_add_us(ktime_get(), interval); + __set_current_state(TASK_INTERRUPTIBLE); + + while (schedule_hrtimeout_range(&wake_time, 0, HRTIMER_MODE_ABS)) { + if (kthread_should_stop()) + break; + } +} + /* * osnoise_main - The osnoise detection kernel thread * @@ -1257,30 +1308,10 @@ static struct cpumask save_cpumask; */ static int osnoise_main(void *data) { - u64 interval; while (!kthread_should_stop()) { - run_osnoise(); - - mutex_lock(&interface_lock); - interval = osnoise_data.sample_period - osnoise_data.sample_runtime; - mutex_unlock(&interface_lock); - - do_div(interval, USEC_PER_MSEC); - - /* - * differently from hwlat_detector, the osnoise tracer can run - * without a pause because preemption is on. - */ - if (interval < 1) { - /* Let synchronize_rcu_tasks() make progress */ - cond_resched_tasks_rcu_qs(); - continue; - } - - if (msleep_interruptible(interval)) - break; + osnoise_sleep(); } return 0; diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c index 9c9eb20dd2..055bc20ecd 100644 --- a/kernel/watch_queue.c +++ b/kernel/watch_queue.c @@ -54,6 +54,7 @@ static void watch_queue_pipe_buf_release(struct pipe_inode_info *pipe, bit += page->index; set_bit(bit, wqueue->notes_bitmap); + generic_pipe_buf_release(pipe, buf); } // No try_steal function => no stealing @@ -112,7 +113,7 @@ static bool post_one_notification(struct watch_queue *wqueue, buf->offset = offset; buf->len = len; buf->flags = PIPE_BUF_FLAG_WHOLE; - pipe->head = head + 1; + smp_store_release(&pipe->head, head + 1); /* vs pipe_read() */ if (!test_and_clear_bit(note, wqueue->notes_bitmap)) { spin_unlock_irq(&pipe->rd_wait.lock); @@ -243,7 +244,8 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes) goto error; } - ret = pipe_resize_ring(pipe, nr_notes); + nr_notes = nr_pages * WATCH_QUEUE_NOTES_PER_PAGE; + ret = pipe_resize_ring(pipe, roundup_pow_of_two(nr_notes)); if (ret < 0) goto error; @@ -268,7 +270,7 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes) wqueue->notes = pages; wqueue->notes_bitmap = bitmap; wqueue->nr_pages = nr_pages; - wqueue->nr_notes = nr_pages * WATCH_QUEUE_NOTES_PER_PAGE; + wqueue->nr_notes = nr_notes; return 0; error_p: @@ -320,7 +322,7 @@ long watch_queue_set_filter(struct pipe_inode_info *pipe, tf[i].info_mask & WATCH_INFO_LENGTH) goto err_filter; /* Ignore any unknown types */ - if (tf[i].type >= sizeof(wfilter->type_filter) * 8) + if (tf[i].type >= WATCH_TYPE__NR) continue; nr_filter++; } @@ -336,7 +338,7 @@ long watch_queue_set_filter(struct pipe_inode_info *pipe, q = wfilter->filters; for (i = 0; i < filter.nr_filters; i++) { - if (tf[i].type >= sizeof(wfilter->type_filter) * BITS_PER_LONG) + if (tf[i].type >= WATCH_TYPE__NR) continue; q->type = tf[i].type; @@ -371,6 +373,7 @@ static void __put_watch_queue(struct kref *kref) for (i = 0; i < wqueue->nr_pages; i++) __free_page(wqueue->notes[i]); + bitmap_free(wqueue->notes_bitmap); wfilter = rcu_access_pointer(wqueue->filter); if (wfilter) @@ -566,7 +569,7 @@ void watch_queue_clear(struct watch_queue *wqueue) rcu_read_lock(); spin_lock_bh(&wqueue->lock); - /* Prevent new additions and prevent notifications from happening */ + /* Prevent new notifications from being stored. */ wqueue->defunct = true; while (!hlist_empty(&wqueue->watches)) { diff --git a/lib/Kconfig b/lib/Kconfig index 5e7165e6a3..fa4b10322e 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -45,7 +45,6 @@ config BITREVERSE config HAVE_ARCH_BITREVERSE bool default n - depends on BITREVERSE help This option enables the use of hardware bit-reversal instructions on architectures which support such operations. diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c index 4ff03fb262..41f36ad8b0 100644 --- a/net/dsa/dsa.c +++ b/net/dsa/dsa.c @@ -349,7 +349,6 @@ void dsa_flush_workqueue(void) { flush_workqueue(dsa_owq); } -EXPORT_SYMBOL_GPL(dsa_flush_workqueue); int dsa_devlink_param_get(struct devlink *dl, u32 id, struct devlink_param_gset_ctx *ctx) diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h index 33ab7d7af9..a5c9bc7b66 100644 --- a/net/dsa/dsa_priv.h +++ b/net/dsa/dsa_priv.h @@ -170,6 +170,7 @@ void dsa_tag_driver_put(const struct dsa_device_ops *ops); const struct dsa_device_ops *dsa_find_tagger_by_name(const char *buf); bool dsa_schedule_work(struct work_struct *work); +void dsa_flush_workqueue(void); const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops); static inline int dsa_tag_protocol_overhead(const struct dsa_device_ops *ops)