From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/gpu/host1x/context.c | 187 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 187 insertions(+) create mode 100644 drivers/gpu/host1x/context.c (limited to 'drivers/gpu/host1x/context.c') diff --git a/drivers/gpu/host1x/context.c b/drivers/gpu/host1x/context.c new file mode 100644 index 000000000..94ecc8769 --- /dev/null +++ b/drivers/gpu/host1x/context.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2021, NVIDIA Corporation. + */ + +#include +#include +#include +#include +#include +#include +#include + +#include "context.h" +#include "dev.h" + +static void host1x_memory_context_release(struct device *dev) +{ + /* context device is freed in host1x_memory_context_list_free() */ +} + +int host1x_memory_context_list_init(struct host1x *host1x) +{ + struct host1x_memory_context_list *cdl = &host1x->context_list; + struct device_node *node = host1x->dev->of_node; + struct host1x_memory_context *ctx; + unsigned int devs, i; + int err; + + cdl->devs = NULL; + cdl->len = 0; + mutex_init(&cdl->lock); + + err = of_property_count_u32_elems(node, "iommu-map"); + if (err < 0) + return 0; + + devs = 0; + + for (i = 0; i < err / 4; i++) { + u32 length; + + of_property_read_u32_index(node, "iommu-map", i * 4 + 3, &length); + devs += length; + } + + cdl->len = devs; + cdl->devs = kzalloc_objs(*cdl->devs, cdl->len); + if (!cdl->devs) + return -ENOMEM; + + for (i = 0; i < cdl->len; i++) { + ctx = &cdl->devs[i]; + + ctx->host = host1x; + + device_initialize(&ctx->dev); + + /* + * Due to an issue with T194 NVENC, only 38 bits can be used. + * Anyway, 256GiB of IOVA ought to be enough for anyone. + */ + ctx->dma_mask = DMA_BIT_MASK(38); + ctx->dev.dma_mask = &ctx->dma_mask; + ctx->dev.coherent_dma_mask = ctx->dma_mask; + dev_set_name(&ctx->dev, "host1x-ctx.%d", i); + ctx->dev.bus = &host1x_context_device_bus_type; + ctx->dev.parent = host1x->dev; + ctx->dev.release = host1x_memory_context_release; + + ctx->dev.dma_parms = &ctx->dma_parms; + dma_set_max_seg_size(&ctx->dev, UINT_MAX); + + err = device_add(&ctx->dev); + if (err) { + dev_err(host1x->dev, "could not add context device %d: %d\n", i, err); + put_device(&ctx->dev); + goto unreg_devices; + } + + err = of_dma_configure_id(&ctx->dev, node, true, &i); + if (err) { + dev_err(host1x->dev, "IOMMU configuration failed for context device %d: %d\n", + i, err); + device_unregister(&ctx->dev); + goto unreg_devices; + } + + if (!tegra_dev_iommu_get_stream_id(&ctx->dev, &ctx->stream_id) || + !device_iommu_mapped(&ctx->dev)) { + dev_err(host1x->dev, "Context device %d has no IOMMU!\n", i); + device_unregister(&ctx->dev); + + /* + * This means that if IOMMU is disabled but context devices + * are defined in the device tree, Host1x will fail to probe. + * That's probably OK in this time and age. + */ + err = -EINVAL; + + goto unreg_devices; + } + } + + return 0; + +unreg_devices: + while (i--) + device_unregister(&cdl->devs[i].dev); + + kfree(cdl->devs); + cdl->devs = NULL; + cdl->len = 0; + + return err; +} + +void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl) +{ + unsigned int i; + + for (i = 0; i < cdl->len; i++) + device_unregister(&cdl->devs[i].dev); + + kfree(cdl->devs); + cdl->len = 0; +} + +struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x, + struct device *dev, + struct pid *pid) +{ + struct host1x_memory_context_list *cdl = &host1x->context_list; + struct host1x_memory_context *free = NULL; + int i; + + if (!cdl->len) + return ERR_PTR(-EOPNOTSUPP); + + mutex_lock(&cdl->lock); + + for (i = 0; i < cdl->len; i++) { + struct host1x_memory_context *cd = &cdl->devs[i]; + + if (cd->dev.iommu->iommu_dev != dev->iommu->iommu_dev) + continue; + + if (cd->owner == pid) { + refcount_inc(&cd->ref); + mutex_unlock(&cdl->lock); + return cd; + } else if (!cd->owner && !free) { + free = cd; + } + } + + if (!free) { + mutex_unlock(&cdl->lock); + return ERR_PTR(-EBUSY); + } + + refcount_set(&free->ref, 1); + free->owner = get_pid(pid); + + mutex_unlock(&cdl->lock); + + return free; +} +EXPORT_SYMBOL_GPL(host1x_memory_context_alloc); + +void host1x_memory_context_get(struct host1x_memory_context *cd) +{ + refcount_inc(&cd->ref); +} +EXPORT_SYMBOL_GPL(host1x_memory_context_get); + +void host1x_memory_context_put(struct host1x_memory_context *cd) +{ + struct host1x_memory_context_list *cdl = &cd->host->context_list; + + if (refcount_dec_and_mutex_lock(&cd->ref, &cdl->lock)) { + put_pid(cd->owner); + cd->owner = NULL; + mutex_unlock(&cdl->lock); + } +} +EXPORT_SYMBOL_GPL(host1x_memory_context_put); -- cgit v1.3.1