From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- io_uring/tctx.c | 424 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 424 insertions(+) create mode 100644 io_uring/tctx.c (limited to 'io_uring/tctx.c') diff --git a/io_uring/tctx.c b/io_uring/tctx.c new file mode 100644 index 000000000..466b7300e --- /dev/null +++ b/io_uring/tctx.c @@ -0,0 +1,424 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include + +#include + +#include "io_uring.h" +#include "tctx.h" +#include "bpf_filter.h" + +static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx, + struct task_struct *task) +{ + struct io_wq_hash *hash; + struct io_wq_data data; + unsigned int concurrency; + + mutex_lock(&ctx->uring_lock); + hash = ctx->hash_map; + if (!hash) { + hash = kzalloc_obj(*hash); + if (!hash) { + mutex_unlock(&ctx->uring_lock); + return ERR_PTR(-ENOMEM); + } + refcount_set(&hash->refs, 1); + init_waitqueue_head(&hash->wait); + ctx->hash_map = hash; + } + mutex_unlock(&ctx->uring_lock); + + data.hash = hash; + data.task = task; + + /* Do QD, or 4 * CPUS, whatever is smallest */ + concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); + + return io_wq_create(concurrency, &data); +} + +void io_uring_free_tctx(struct task_struct *tsk) +{ + struct io_uring_task *tctx = tsk->io_uring; + struct io_tctx_node *node; + unsigned long index; + + /* + * Fault injection forcing allocation errors in the xa_store() path + * can lead to xa_empty() returning false, even though no actual + * node is stored in the xarray. Until that gets sorted out, attempt + * an iteration here and warn if any entries are found. + */ + if (tctx) { + xa_for_each(&tctx->xa, index, node) { + WARN_ON_ONCE(1); + break; + } + WARN_ON_ONCE(tctx->io_wq); + WARN_ON_ONCE(tctx->cached_refs); + + percpu_counter_destroy(&tctx->inflight); + kfree(tctx); + tsk->io_uring = NULL; + } +} + +void __io_uring_free(struct task_struct *tsk) +{ + io_uring_free_tctx(tsk); + if (tsk->io_uring_restrict) { + io_put_bpf_filters(tsk->io_uring_restrict); + kfree(tsk->io_uring_restrict); + tsk->io_uring_restrict = NULL; + } +} + +__cold struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task, + struct io_ring_ctx *ctx) +{ + struct io_uring_task *tctx; + int ret; + + tctx = kzalloc_obj(*tctx); + if (unlikely(!tctx)) + return ERR_PTR(-ENOMEM); + + ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); + if (unlikely(ret)) { + kfree(tctx); + return ERR_PTR(ret); + } + + tctx->io_wq = io_init_wq_offload(ctx, task); + if (IS_ERR(tctx->io_wq)) { + ret = PTR_ERR(tctx->io_wq); + percpu_counter_destroy(&tctx->inflight); + kfree(tctx); + return ERR_PTR(ret); + } + + tctx->task = task; + xa_init(&tctx->xa); + init_waitqueue_head(&tctx->wait); + atomic_set(&tctx->in_cancel, 0); + atomic_set(&tctx->inflight_tracked, 0); + mpscq_init(&tctx->task_list, &tctx->task_head); + INIT_WORK(&tctx->fallback_work, io_tctx_fallback_work); + init_task_work(&tctx->task_work, tctx_task_work); + return tctx; +} + +static int io_tctx_install_node(struct io_ring_ctx *ctx, + struct io_uring_task *tctx) +{ + struct io_tctx_node *node; + int ret; + + if (xa_load(&tctx->xa, (unsigned long)ctx)) + return 0; + + node = kmalloc_obj(*node); + if (!node) + return -ENOMEM; + node->ctx = ctx; + node->task = current; + + ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx, + node, GFP_KERNEL)); + if (ret) { + kfree(node); + return ret; + } + + mutex_lock(&ctx->tctx_lock); + list_add(&node->ctx_node, &ctx->tctx_list); + mutex_unlock(&ctx->tctx_lock); + return 0; +} + +int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) +{ + struct io_uring_task *tctx = current->io_uring; + bool new_tctx = false; + int ret; + + if (unlikely(!tctx)) { + tctx = io_uring_alloc_task_context(current, ctx); + if (IS_ERR(tctx)) + return PTR_ERR(tctx); + new_tctx = true; + + if (data_race(ctx->int_flags) & IO_RING_F_IOWQ_LIMITS_SET) { + unsigned int limits[2]; + + mutex_lock(&ctx->uring_lock); + limits[0] = ctx->iowq_limits[0]; + limits[1] = ctx->iowq_limits[1]; + mutex_unlock(&ctx->uring_lock); + + ret = io_wq_max_workers(tctx->io_wq, limits); + if (ret) + goto err_free; + } + } + + /* + * Re-activate io-wq keepalive on any new io_uring usage. The wq may have + * been marked for idle-exit when the task temporarily had no active + * io_uring instances. + */ + if (tctx->io_wq) + io_wq_set_exit_on_idle(tctx->io_wq, false); + + if (new_tctx) + current->io_uring = tctx; + + ret = io_tctx_install_node(ctx, tctx); + if (!ret) + return 0; +err_free: + if (new_tctx) { + current->io_uring = NULL; + if (tctx->io_wq) { + io_wq_exit_start(tctx->io_wq); + io_wq_put_and_exit(tctx->io_wq); + } + percpu_counter_destroy(&tctx->inflight); + kfree(tctx); + } + return ret; +} + +int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx) +{ + int ret; + + if (ctx->flags & IORING_SETUP_SINGLE_ISSUER + && ctx->submitter_task != current) + return -EEXIST; + + ret = __io_uring_add_tctx_node(ctx); + if (ret) + return ret; + + current->io_uring->last = ctx; + return 0; +} + +/* + * Remove this io_uring_file -> task mapping. + */ +__cold void io_uring_del_tctx_node(unsigned long index) +{ + struct io_uring_task *tctx = current->io_uring; + struct io_tctx_node *node; + + if (!tctx) + return; + node = xa_erase(&tctx->xa, index); + if (!node) + return; + + WARN_ON_ONCE(current != node->task); + WARN_ON_ONCE(list_empty(&node->ctx_node)); + + mutex_lock(&node->ctx->tctx_lock); + list_del(&node->ctx_node); + mutex_unlock(&node->ctx->tctx_lock); + + if (tctx->last == node->ctx) + tctx->last = NULL; + kfree(node); + + if (xa_empty(&tctx->xa) && tctx->io_wq) + io_wq_set_exit_on_idle(tctx->io_wq, true); +} + +__cold void io_uring_clean_tctx(struct io_uring_task *tctx) +{ + struct io_wq *wq = tctx->io_wq; + struct io_tctx_node *node; + unsigned long index; + + xa_for_each(&tctx->xa, index, node) { + io_uring_del_tctx_node(index); + cond_resched(); + } + if (wq) { + /* + * Must be after io_uring_del_tctx_node() (removes nodes under + * uring_lock) to avoid race with io_uring_try_cancel_iowq(). + */ + io_wq_put_and_exit(wq); + tctx->io_wq = NULL; + } +} + +void io_uring_unreg_ringfd(void) +{ + struct io_uring_task *tctx = current->io_uring; + int i; + + for (i = 0; i < IO_RINGFD_REG_MAX; i++) { + if (tctx->registered_rings[i]) { + fput(tctx->registered_rings[i]); + tctx->registered_rings[i] = NULL; + } + } +} + +int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, + int start, int end) +{ + int offset, idx; + for (offset = start; offset < end; offset++) { + idx = array_index_nospec(offset, IO_RINGFD_REG_MAX); + if (tctx->registered_rings[idx]) + continue; + + tctx->registered_rings[idx] = file; + return idx; + } + return -EBUSY; +} + +static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, + int start, int end) +{ + struct file *file; + int offset; + + file = fget(fd); + if (!file) { + return -EBADF; + } else if (!io_is_uring_fops(file)) { + fput(file); + return -EOPNOTSUPP; + } + offset = io_ring_add_registered_file(tctx, file, start, end); + if (offset < 0) + fput(file); + return offset; +} + +/* + * Register a ring fd to avoid fdget/fdput for each io_uring_enter() + * invocation. User passes in an array of struct io_uring_rsrc_update + * with ->data set to the ring_fd, and ->offset given for the desired + * index. If no index is desired, application may set ->offset == -1U + * and we'll find an available index. Returns number of entries + * successfully processed, or < 0 on error if none were processed. + */ +int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, + unsigned nr_args) +{ + struct io_uring_rsrc_update __user *arg = __arg; + struct io_uring_rsrc_update reg; + struct io_uring_task *tctx; + int ret, i; + + if (!nr_args || nr_args > IO_RINGFD_REG_MAX) + return -EINVAL; + + mutex_unlock(&ctx->uring_lock); + ret = __io_uring_add_tctx_node(ctx); + mutex_lock(&ctx->uring_lock); + if (ret) + return ret; + + tctx = current->io_uring; + for (i = 0; i < nr_args; i++) { + int start, end; + + if (copy_from_user(®, &arg[i], sizeof(reg))) { + ret = -EFAULT; + break; + } + + if (reg.resv) { + ret = -EINVAL; + break; + } + + if (reg.offset == -1U) { + start = 0; + end = IO_RINGFD_REG_MAX; + } else { + if (reg.offset >= IO_RINGFD_REG_MAX) { + ret = -EINVAL; + break; + } + start = reg.offset; + end = start + 1; + } + + ret = io_ring_add_registered_fd(tctx, reg.data, start, end); + if (ret < 0) + break; + + reg.offset = ret; + if (copy_to_user(&arg[i], ®, sizeof(reg))) { + fput(tctx->registered_rings[reg.offset]); + tctx->registered_rings[reg.offset] = NULL; + ret = -EFAULT; + break; + } + } + + return i ? i : ret; +} + +int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, + unsigned nr_args) +{ + struct io_uring_rsrc_update __user *arg = __arg; + struct io_uring_task *tctx = current->io_uring; + struct io_uring_rsrc_update reg; + int ret = 0, i; + + if (!nr_args || nr_args > IO_RINGFD_REG_MAX) + return -EINVAL; + if (!tctx) + return 0; + + for (i = 0; i < nr_args; i++) { + if (copy_from_user(®, &arg[i], sizeof(reg))) { + ret = -EFAULT; + break; + } + if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { + ret = -EINVAL; + break; + } + + reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); + if (tctx->registered_rings[reg.offset]) { + fput(tctx->registered_rings[reg.offset]); + tctx->registered_rings[reg.offset] = NULL; + } + } + + return i ? i : ret; +} + +int __io_uring_fork(struct task_struct *tsk) +{ + struct io_restriction *res, *src = tsk->io_uring_restrict; + + /* Don't leave it dangling on error */ + tsk->io_uring_restrict = NULL; + + res = kzalloc_obj(*res, GFP_KERNEL_ACCOUNT); + if (!res) + return -ENOMEM; + + tsk->io_uring_restrict = res; + io_restriction_clone(res, src); + return 0; +} -- cgit v1.3.1