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 --- fs/afs/server.c | 631 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 631 insertions(+) create mode 100644 fs/afs/server.c (limited to 'fs/afs/server.c') diff --git a/fs/afs/server.c b/fs/afs/server.c new file mode 100644 index 000000000..0fe162ea2 --- /dev/null +++ b/fs/afs/server.c @@ -0,0 +1,631 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS server record management + * + * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include "afs_fs.h" +#include "internal.h" +#include "protocol_yfs.h" + +static unsigned afs_server_gc_delay = 10; /* Server record timeout in seconds */ +static atomic_t afs_server_debug_id; + +static void __afs_put_server(struct afs_net *, struct afs_server *); +static void afs_server_timer(struct timer_list *timer); +static void afs_server_destroyer(struct work_struct *work); + +/* + * Find a server by one of its addresses. + */ +struct afs_server *afs_find_server(const struct rxrpc_peer *peer) +{ + struct afs_server *server = (struct afs_server *)rxrpc_kernel_get_peer_data(peer); + + if (!server) + return NULL; + return afs_use_server(server, false, afs_server_trace_use_cm_call); +} + +/* + * Look up a server by its UUID and mark it active. The caller must hold + * cell->fs_lock. + */ +static struct afs_server *afs_find_server_by_uuid(struct afs_cell *cell, const uuid_t *uuid) +{ + struct afs_server *server; + struct rb_node *p; + int diff; + + _enter("%pU", uuid); + + p = cell->fs_servers.rb_node; + while (p) { + server = rb_entry(p, struct afs_server, uuid_rb); + + diff = memcmp(uuid, &server->uuid, sizeof(*uuid)); + if (diff < 0) { + p = p->rb_left; + } else if (diff > 0) { + p = p->rb_right; + } else { + if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) + return NULL; /* Need a write lock */ + afs_use_server(server, true, afs_server_trace_use_by_uuid); + return server; + } + } + + return NULL; +} + +/* + * Install a server record in the cell tree. The caller must hold an exclusive + * lock on cell->fs_lock. + */ +static struct afs_server *afs_install_server(struct afs_cell *cell, + struct afs_server **candidate) +{ + struct afs_server *server; + struct afs_net *net = cell->net; + struct rb_node **pp, *p; + int diff; + + _enter("%p", candidate); + + /* Firstly install the server in the UUID lookup tree */ + pp = &cell->fs_servers.rb_node; + p = NULL; + while (*pp) { + p = *pp; + _debug("- consider %p", p); + server = rb_entry(p, struct afs_server, uuid_rb); + diff = memcmp(&(*candidate)->uuid, &server->uuid, sizeof(uuid_t)); + if (diff < 0) + pp = &(*pp)->rb_left; + else if (diff > 0) + pp = &(*pp)->rb_right; + else + goto exists; + } + + server = *candidate; + *candidate = NULL; + rb_link_node(&server->uuid_rb, p, pp); + rb_insert_color(&server->uuid_rb, &cell->fs_servers); + write_seqlock(&net->fs_lock); + hlist_add_head_rcu(&server->proc_link, &net->fs_proc); + write_sequnlock(&net->fs_lock); + + afs_get_cell(cell, afs_cell_trace_get_server); + +exists: + afs_use_server(server, true, afs_server_trace_use_install); + return server; +} + +/* + * Allocate a new server record and mark it as active but uncreated. + */ +static struct afs_server *afs_alloc_server(struct afs_cell *cell, const uuid_t *uuid) +{ + struct afs_server *server; + struct afs_net *net = cell->net; + + _enter(""); + + server = kzalloc_obj(struct afs_server); + if (!server) + return NULL; + + refcount_set(&server->ref, 1); + atomic_set(&server->active, 0); + __set_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + server->debug_id = atomic_inc_return(&afs_server_debug_id); + server->uuid = *uuid; + rwlock_init(&server->fs_lock); + INIT_WORK(&server->destroyer, &afs_server_destroyer); + timer_setup(&server->timer, afs_server_timer, 0); + INIT_LIST_HEAD(&server->volumes); + init_waitqueue_head(&server->probe_wq); + mutex_init(&server->cm_token_lock); + INIT_LIST_HEAD(&server->probe_link); + INIT_HLIST_NODE(&server->proc_link); + spin_lock_init(&server->probe_lock); + server->cell = cell; + server->rtt = UINT_MAX; + server->service_id = FS_SERVICE; + server->probe_counter = 1; + server->probed_at = jiffies - LONG_MAX / 2; + + afs_inc_servers_outstanding(net); + _leave(" = %p", server); + return server; +} + +/* + * Look up an address record for a server + */ +static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_server *server, + struct key *key) +{ + struct afs_vl_cursor vc; + struct afs_addr_list *alist = NULL; + int ret; + + ret = -ERESTARTSYS; + if (afs_begin_vlserver_operation(&vc, server->cell, key)) { + while (afs_select_vlserver(&vc)) { + if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags)) + alist = afs_yfsvl_get_endpoints(&vc, &server->uuid); + else + alist = afs_vl_get_addrs_u(&vc, &server->uuid); + } + + ret = afs_end_vlserver_operation(&vc); + } + + return ret < 0 ? ERR_PTR(ret) : alist; +} + +/* + * Get or create a fileserver record and return it with an active-use count on + * it. + */ +struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key, + const uuid_t *uuid, u32 addr_version) +{ + struct afs_addr_list *alist = NULL; + struct afs_server *server, *candidate = NULL; + bool creating = false; + int ret; + + _enter("%p,%pU", cell->net, uuid); + + down_read(&cell->fs_lock); + server = afs_find_server_by_uuid(cell, uuid); + /* Won't see servers marked uncreated. */ + up_read(&cell->fs_lock); + + if (server) { + timer_delete_sync(&server->timer); + if (test_bit(AFS_SERVER_FL_CREATING, &server->flags)) + goto wait_for_creation; + if (server->addr_version != addr_version) + set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags); + return server; + } + + candidate = afs_alloc_server(cell, uuid); + if (!candidate) { + afs_put_addrlist(alist, afs_alist_trace_put_server_oom); + return ERR_PTR(-ENOMEM); + } + + down_write(&cell->fs_lock); + server = afs_install_server(cell, &candidate); + if (test_bit(AFS_SERVER_FL_CREATING, &server->flags)) { + /* We need to wait for creation to complete. */ + up_write(&cell->fs_lock); + goto wait_for_creation; + } + if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) { + set_bit(AFS_SERVER_FL_CREATING, &server->flags); + clear_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + creating = true; + } + up_write(&cell->fs_lock); + timer_delete_sync(&server->timer); + + /* If we get to create the server, we look up the addresses and then + * immediately dispatch an asynchronous probe to each interface on the + * fileserver. This will make sure the repeat-probing service is + * started. + */ + if (creating) { + alist = afs_vl_lookup_addrs(server, key); + if (IS_ERR(alist)) { + ret = PTR_ERR(alist); + goto create_failed; + } + + ret = afs_fs_probe_fileserver(cell->net, server, alist, key); + if (ret) + goto create_failed; + + clear_and_wake_up_bit(AFS_SERVER_FL_CREATING, &server->flags); + } + +out: + afs_put_addrlist(alist, afs_alist_trace_put_server_create); + if (candidate) { + kfree(rcu_access_pointer(server->endpoint_state)); + kfree(candidate); + afs_dec_servers_outstanding(cell->net); + } + return server ?: ERR_PTR(ret); + +wait_for_creation: + afs_see_server(server, afs_server_trace_wait_create); + wait_on_bit(&server->flags, AFS_SERVER_FL_CREATING, TASK_UNINTERRUPTIBLE); + if (test_bit_acquire(AFS_SERVER_FL_UNCREATED, &server->flags)) { + /* Barrier: read flag before error */ + ret = READ_ONCE(server->create_error); + afs_put_server(cell->net, server, afs_server_trace_unuse_create_fail); + server = NULL; + goto out; + } + + ret = 0; + goto out; + +create_failed: + down_write(&cell->fs_lock); + + WRITE_ONCE(server->create_error, ret); + smp_wmb(); /* Barrier: set error before flag. */ + set_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + + clear_and_wake_up_bit(AFS_SERVER_FL_CREATING, &server->flags); + + if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) { + clear_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + creating = true; + } + afs_unuse_server(cell->net, server, afs_server_trace_unuse_create_fail); + server = NULL; + + up_write(&cell->fs_lock); + goto out; +} + +/* + * Set/reduce a server's timer. + */ +static void afs_set_server_timer(struct afs_server *server, unsigned int delay_secs) +{ + mod_timer(&server->timer, jiffies + delay_secs * HZ); +} + +/* + * Get a reference on a server object. + */ +struct afs_server *afs_get_server(struct afs_server *server, + enum afs_server_trace reason) +{ + unsigned int a; + int r; + + __refcount_inc(&server->ref, &r); + a = atomic_read(&server->active); + trace_afs_server(server->debug_id, r + 1, a, reason); + return server; +} + +/* + * Get an active count on a server object and maybe remove from the inactive + * list. + */ +struct afs_server *afs_use_server(struct afs_server *server, bool activate, + enum afs_server_trace reason) +{ + unsigned int a; + int r; + + __refcount_inc(&server->ref, &r); + a = atomic_inc_return(&server->active); + if (a == 1 && activate && + !test_bit(AFS_SERVER_FL_EXPIRED, &server->flags)) + timer_delete(&server->timer); + + trace_afs_server(server->debug_id, r + 1, a, reason); + return server; +} + +/* + * Release a reference on a server record. + */ +void afs_put_server(struct afs_net *net, struct afs_server *server, + enum afs_server_trace reason) +{ + unsigned int a, debug_id; + bool zero; + int r; + + if (!server) + return; + + debug_id = server->debug_id; + a = atomic_read(&server->active); + zero = __refcount_dec_and_test(&server->ref, &r); + trace_afs_server(debug_id, r - 1, a, reason); + if (unlikely(zero)) + __afs_put_server(net, server); +} + +/* + * Drop an active count on a server object without updating the last-unused + * time. + */ +void afs_unuse_server_notime(struct afs_net *net, struct afs_server *server, + enum afs_server_trace reason) +{ + if (!server) + return; + + if (atomic_dec_and_test(&server->active)) { + if (test_bit(AFS_SERVER_FL_EXPIRED, &server->flags) || + READ_ONCE(server->cell->state) >= AFS_CELL_REMOVING) + schedule_work(&server->destroyer); + } + + afs_put_server(net, server, reason); +} + +/* + * Drop an active count on a server object. + */ +void afs_unuse_server(struct afs_net *net, struct afs_server *server, + enum afs_server_trace reason) +{ + if (!server) + return; + + if (atomic_dec_and_test(&server->active)) { + if (!test_bit(AFS_SERVER_FL_EXPIRED, &server->flags) && + READ_ONCE(server->cell->state) < AFS_CELL_REMOVING) { + time64_t unuse_time = ktime_get_real_seconds(); + + server->unuse_time = unuse_time; + afs_set_server_timer(server, afs_server_gc_delay); + } else { + schedule_work(&server->destroyer); + } + } + + afs_put_server(net, server, reason); +} + +static void afs_server_rcu(struct rcu_head *rcu) +{ + struct afs_server *server = container_of(rcu, struct afs_server, rcu); + + trace_afs_server(server->debug_id, refcount_read(&server->ref), + atomic_read(&server->active), afs_server_trace_free); + afs_put_endpoint_state(rcu_access_pointer(server->endpoint_state), + afs_estate_trace_put_server); + afs_put_cell(server->cell, afs_cell_trace_put_server); + kfree(server->cm_rxgk_appdata.data); + kfree(server); +} + +static void __afs_put_server(struct afs_net *net, struct afs_server *server) +{ + call_rcu(&server->rcu, afs_server_rcu); + afs_dec_servers_outstanding(net); +} + +static void afs_give_up_callbacks(struct afs_net *net, struct afs_server *server) +{ + struct afs_endpoint_state *estate = rcu_access_pointer(server->endpoint_state); + struct afs_addr_list *alist = estate->addresses; + + afs_fs_give_up_all_callbacks(net, server, &alist->addrs[alist->preferred], NULL); +} + +/* + * Check to see if the server record has expired. + */ +static bool afs_has_server_expired(const struct afs_server *server) +{ + time64_t expires_at; + + if (atomic_read(&server->active)) + return false; + + if (server->cell->net->live || + server->cell->state >= AFS_CELL_REMOVING) { + trace_afs_server(server->debug_id, refcount_read(&server->ref), + 0, afs_server_trace_purging); + return true; + } + + expires_at = server->unuse_time; + if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) && + !test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags)) + expires_at += afs_server_gc_delay; + + return ktime_get_real_seconds() > expires_at; +} + +/* + * Remove a server record from it's parent cell's database. + */ +static bool afs_remove_server_from_cell(struct afs_server *server) +{ + struct afs_cell *cell = server->cell; + + down_write(&cell->fs_lock); + + if (!afs_has_server_expired(server)) { + up_write(&cell->fs_lock); + return false; + } + + set_bit(AFS_SERVER_FL_EXPIRED, &server->flags); + _debug("expire %pU %u", &server->uuid, atomic_read(&server->active)); + afs_see_server(server, afs_server_trace_see_expired); + rb_erase(&server->uuid_rb, &cell->fs_servers); + up_write(&cell->fs_lock); + return true; +} + +static void afs_server_destroyer(struct work_struct *work) +{ + struct afs_endpoint_state *estate; + struct afs_server *server = container_of(work, struct afs_server, destroyer); + struct afs_net *net = server->cell->net; + + afs_see_server(server, afs_server_trace_see_destroyer); + + if (test_bit(AFS_SERVER_FL_EXPIRED, &server->flags)) + return; + + if (!afs_remove_server_from_cell(server)) + return; + + timer_shutdown_sync(&server->timer); + cancel_work(&server->destroyer); + + if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags)) + afs_give_up_callbacks(net, server); + + /* Unbind the rxrpc_peer records from the server. */ + estate = rcu_access_pointer(server->endpoint_state); + if (estate) + afs_set_peer_appdata(server, estate->addresses, NULL); + + write_seqlock(&net->fs_lock); + list_del_init(&server->probe_link); + if (!hlist_unhashed(&server->proc_link)) + hlist_del_rcu(&server->proc_link); + write_sequnlock(&net->fs_lock); + + afs_put_server(net, server, afs_server_trace_destroy); +} + +static void afs_server_timer(struct timer_list *timer) +{ + struct afs_server *server = container_of(timer, struct afs_server, timer); + + afs_see_server(server, afs_server_trace_see_timer); + if (!test_bit(AFS_SERVER_FL_EXPIRED, &server->flags)) + schedule_work(&server->destroyer); +} + +/* + * Wake up all the servers in a cell so that they can purge themselves. + */ +void afs_purge_servers(struct afs_cell *cell) +{ + struct afs_server *server; + struct rb_node *rb; + + down_read(&cell->fs_lock); + for (rb = rb_first(&cell->fs_servers); rb; rb = rb_next(rb)) { + server = rb_entry(rb, struct afs_server, uuid_rb); + afs_see_server(server, afs_server_trace_see_purge); + schedule_work(&server->destroyer); + } + up_read(&cell->fs_lock); +} + +/* + * Wait for outstanding servers. + */ +void afs_wait_for_servers(struct afs_net *net) +{ + _enter(""); + + atomic_dec(&net->servers_outstanding); + wait_var_event(&net->servers_outstanding, + !atomic_read(&net->servers_outstanding)); + _leave(""); +} + +/* + * Get an update for a server's address list. + */ +static noinline bool afs_update_server_record(struct afs_operation *op, + struct afs_server *server, + struct key *key) +{ + struct afs_endpoint_state *estate; + struct afs_addr_list *alist; + bool has_addrs; + + _enter(""); + + trace_afs_server(server->debug_id, refcount_read(&server->ref), + atomic_read(&server->active), + afs_server_trace_update); + + alist = afs_vl_lookup_addrs(server, op->key); + if (IS_ERR(alist)) { + rcu_read_lock(); + estate = rcu_dereference(server->endpoint_state); + has_addrs = estate->addresses; + rcu_read_unlock(); + + if ((PTR_ERR(alist) == -ERESTARTSYS || + PTR_ERR(alist) == -EINTR) && + (op->flags & AFS_OPERATION_UNINTR) && + has_addrs) { + _leave(" = t [intr]"); + return true; + } + afs_op_set_error(op, PTR_ERR(alist)); + _leave(" = f [%d]", afs_op_error(op)); + return false; + } + + if (server->addr_version != alist->version) + afs_fs_probe_fileserver(op->net, server, alist, key); + + afs_put_addrlist(alist, afs_alist_trace_put_server_update); + _leave(" = t"); + return true; +} + +/* + * See if a server's address list needs updating. + */ +bool afs_check_server_record(struct afs_operation *op, struct afs_server *server, + struct key *key) +{ + bool success; + int ret, retries = 0; + + _enter(""); + + ASSERT(server); + +retry: + if (test_bit(AFS_SERVER_FL_UPDATING, &server->flags)) + goto wait; + if (test_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags)) + goto update; + _leave(" = t [good]"); + return true; + +update: + if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) { + clear_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags); + success = afs_update_server_record(op, server, key); + clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags); + wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING); + _leave(" = %d", success); + return success; + } + +wait: + ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING, + (op->flags & AFS_OPERATION_UNINTR) ? + TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE); + if (ret == -ERESTARTSYS) { + afs_op_set_error(op, ret); + _leave(" = f [intr]"); + return false; + } + + retries++; + if (retries == 4) { + _leave(" = f [stale]"); + ret = -ESTALE; + return false; + } + goto retry; +} -- cgit v1.3.1