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/channel.c | 185 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 185 insertions(+) create mode 100644 drivers/gpu/host1x/channel.c (limited to 'drivers/gpu/host1x/channel.c') diff --git a/drivers/gpu/host1x/channel.c b/drivers/gpu/host1x/channel.c new file mode 100644 index 000000000..ca5d0f51c --- /dev/null +++ b/drivers/gpu/host1x/channel.c @@ -0,0 +1,185 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Tegra host1x Channel + * + * Copyright (c) 2010-2013, NVIDIA Corporation. + */ + +#include +#include + +#include "channel.h" +#include "dev.h" +#include "job.h" + +/* Constructor for the host1x device list */ +int host1x_channel_list_init(struct host1x_channel_list *chlist, + unsigned int num_channels) +{ + chlist->channels = kzalloc_objs(struct host1x_channel, num_channels); + if (!chlist->channels) + return -ENOMEM; + + chlist->allocated_channels = bitmap_zalloc(num_channels, GFP_KERNEL); + if (!chlist->allocated_channels) { + kfree(chlist->channels); + return -ENOMEM; + } + + mutex_init(&chlist->lock); + + return 0; +} + +void host1x_channel_list_free(struct host1x_channel_list *chlist) +{ + bitmap_free(chlist->allocated_channels); + kfree(chlist->channels); +} + +int host1x_job_submit(struct host1x_job *job) +{ + struct host1x *host = dev_get_drvdata(job->channel->dev->parent); + + return host1x_hw_channel_submit(host, job); +} +EXPORT_SYMBOL(host1x_job_submit); + +struct host1x_channel *host1x_channel_get(struct host1x_channel *channel) +{ + kref_get(&channel->refcount); + + return channel; +} +EXPORT_SYMBOL(host1x_channel_get); + +/** + * host1x_channel_get_index() - Attempt to get channel reference by index + * @host: Host1x device object + * @index: Index of channel + * + * If channel number @index is currently allocated, increase its refcount + * and return a pointer to it. Otherwise, return NULL. + */ +struct host1x_channel *host1x_channel_get_index(struct host1x *host, + unsigned int index) +{ + struct host1x_channel *ch = &host->channel_list.channels[index]; + + if (!kref_get_unless_zero(&ch->refcount)) + return NULL; + + return ch; +} + +void host1x_channel_stop(struct host1x_channel *channel) +{ + struct host1x *host = dev_get_drvdata(channel->dev->parent); + + host1x_hw_cdma_stop(host, &channel->cdma); +} +EXPORT_SYMBOL(host1x_channel_stop); + +/** + * host1x_channel_stop_all() - disable CDMA on allocated channels + * @host: host1x instance + * + * Stop CDMA on allocated channels + */ +void host1x_channel_stop_all(struct host1x *host) +{ + struct host1x_channel_list *chlist = &host->channel_list; + int bit; + + mutex_lock(&chlist->lock); + + for_each_set_bit(bit, chlist->allocated_channels, host->info->nb_channels) + host1x_channel_stop(&chlist->channels[bit]); + + mutex_unlock(&chlist->lock); +} + +static void release_channel(struct kref *kref) +{ + struct host1x_channel *channel = + container_of(kref, struct host1x_channel, refcount); + struct host1x *host = dev_get_drvdata(channel->dev->parent); + struct host1x_channel_list *chlist = &host->channel_list; + + host1x_hw_cdma_stop(host, &channel->cdma); + host1x_cdma_deinit(&channel->cdma); + + clear_bit(channel->id, chlist->allocated_channels); +} + +void host1x_channel_put(struct host1x_channel *channel) +{ + kref_put(&channel->refcount, release_channel); +} +EXPORT_SYMBOL(host1x_channel_put); + +static struct host1x_channel *acquire_unused_channel(struct host1x *host) +{ + struct host1x_channel_list *chlist = &host->channel_list; + unsigned int max_channels = host->info->nb_channels; + unsigned int index; + + mutex_lock(&chlist->lock); + + index = find_first_zero_bit(chlist->allocated_channels, max_channels); + if (index >= max_channels) { + mutex_unlock(&chlist->lock); + dev_err(host->dev, "failed to find free channel\n"); + return NULL; + } + + chlist->channels[index].id = index; + + set_bit(index, chlist->allocated_channels); + + mutex_unlock(&chlist->lock); + + return &chlist->channels[index]; +} + +/** + * host1x_channel_request() - Allocate a channel + * @client: Host1x client this channel will be used to send commands to + * + * Allocates a new host1x channel for @client. May return NULL if CDMA + * initialization fails. + */ +struct host1x_channel *host1x_channel_request(struct host1x_client *client) +{ + struct host1x *host = dev_get_drvdata(client->dev->parent); + struct host1x_channel_list *chlist = &host->channel_list; + struct host1x_channel *channel; + int err; + + channel = acquire_unused_channel(host); + if (!channel) + return NULL; + + kref_init(&channel->refcount); + mutex_init(&channel->submitlock); + channel->client = client; + channel->dev = client->dev; + + err = host1x_hw_channel_init(host, channel, channel->id); + if (err < 0) + goto fail; + + err = host1x_cdma_init(&channel->cdma); + if (err < 0) + goto fail; + + return channel; + +fail: + clear_bit(channel->id, chlist->allocated_channels); + + dev_err(client->dev, "failed to initialize channel\n"); + + return NULL; +} +EXPORT_SYMBOL(host1x_channel_request); -- cgit v1.3.1