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 --- fs/nfs/pnfs_dev.c | 381 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 381 insertions(+) create mode 100644 fs/nfs/pnfs_dev.c (limited to 'fs/nfs/pnfs_dev.c') diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c new file mode 100644 index 000000000..274abdd6d --- /dev/null +++ b/fs/nfs/pnfs_dev.c @@ -0,0 +1,381 @@ +/* + * Device operations for the pnfs client. + * + * Copyright (c) 2002 + * The Regents of the University of Michigan + * All Rights Reserved + * + * Dean Hildebrand + * Garth Goodson + * + * Permission is granted to use, copy, create derivative works, and + * redistribute this software and such derivative works for any purpose, + * so long as the name of the University of Michigan is not used in + * any advertising or publicity pertaining to the use or distribution + * of this software without specific, written prior authorization. If + * the above copyright notice or any other identification of the + * University of Michigan is included in any copy of any portion of + * this software, then the disclaimer below must also be included. + * + * This software is provided as is, without representation or warranty + * of any kind either express or implied, including without limitation + * the implied warranties of merchantability, fitness for a particular + * purpose, or noninfringement. The Regents of the University of + * Michigan shall not be liable for any damages, including special, + * indirect, incidental, or consequential damages, with respect to any + * claim arising out of or in connection with the use of the software, + * even if it has been or is hereafter advised of the possibility of + * such damages. + */ + +#include +#include +#include "nfs4session.h" +#include "internal.h" +#include "pnfs.h" + +#include "nfs4trace.h" + +#define NFSDBG_FACILITY NFSDBG_PNFS + +/* + * Device ID RCU cache. A device ID is unique per server and layout type. + */ +#define NFS4_DEVICE_ID_HASH_BITS 5 +#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS) +#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1) + + +static struct hlist_head nfs4_deviceid_cache[NFS4_DEVICE_ID_HASH_SIZE]; +static DEFINE_SPINLOCK(nfs4_deviceid_lock); + +#ifdef NFS_DEBUG +void +nfs4_print_deviceid(const struct nfs4_deviceid *id) +{ + u32 *p = (u32 *)id; + + dprintk("%s: device id= [%x%x%x%x]\n", __func__, + p[0], p[1], p[2], p[3]); +} +EXPORT_SYMBOL_GPL(nfs4_print_deviceid); +#endif + +static inline u32 +nfs4_deviceid_hash(const struct nfs4_deviceid *id) +{ + unsigned char *cptr = (unsigned char *)id->data; + unsigned int nbytes = NFS4_DEVICEID4_SIZE; + u32 x = 0; + + while (nbytes--) { + x *= 37; + x += *cptr++; + } + return x & NFS4_DEVICE_ID_HASH_MASK; +} + +static struct nfs4_deviceid_node * +_lookup_deviceid(const struct pnfs_layoutdriver_type *ld, + const struct nfs_client *clp, const struct nfs4_deviceid *id, + long hash) +{ + struct nfs4_deviceid_node *d; + + hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node) + if (d->ld == ld && d->nfs_client == clp && + !memcmp(&d->deviceid, id, sizeof(*id))) { + if (atomic_read(&d->ref)) + return d; + else + continue; + } + return NULL; +} + +static struct nfs4_deviceid_node * +nfs4_get_device_info(struct nfs_server *server, + const struct nfs4_deviceid *dev_id, + const struct cred *cred, gfp_t gfp_flags) +{ + struct nfs4_deviceid_node *d = NULL; + struct pnfs_device *pdev = NULL; + struct page **pages = NULL; + u32 max_resp_sz; + int max_pages; + int rc, i; + + /* + * Use the session max response size as the basis for setting + * GETDEVICEINFO's maxcount + */ + max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz; + max_pages = nfs_page_array_len(0, max_resp_sz); + dprintk("%s: server %p max_resp_sz %u max_pages %d\n", + __func__, server, max_resp_sz, max_pages); + + pdev = kzalloc_obj(*pdev, gfp_flags); + if (!pdev) + return NULL; + + pages = kzalloc_objs(struct page *, max_pages, gfp_flags); + if (!pages) + goto out_free_pdev; + + for (i = 0; i < max_pages; i++) { + pages[i] = alloc_page(gfp_flags); + if (!pages[i]) + goto out_free_pages; + } + + memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id)); + pdev->layout_type = server->pnfs_curr_ld->id; + pdev->pages = pages; + pdev->pgbase = 0; + pdev->pglen = max_resp_sz; + pdev->mincount = 0; + pdev->maxcount = max_resp_sz - nfs41_maxgetdevinfo_overhead; + + rc = nfs4_proc_getdeviceinfo(server, pdev, cred); + dprintk("%s getdevice info returns %d\n", __func__, rc); + if (rc) + goto out_free_pages; + + /* + * Found new device, need to decode it and then add it to the + * list of known devices for this mountpoint. + */ + d = server->pnfs_curr_ld->alloc_deviceid_node(server, pdev, + gfp_flags); + if (d && pdev->nocache) + set_bit(NFS_DEVICEID_NOCACHE, &d->flags); + +out_free_pages: + while (--i >= 0) + __free_page(pages[i]); + kfree(pages); +out_free_pdev: + kfree(pdev); + dprintk("<-- %s d %p\n", __func__, d); + return d; +} + +/* + * Lookup a deviceid in cache and get a reference count on it if found + * + * @clp nfs_client associated with deviceid + * @id deviceid to look up + */ +static struct nfs4_deviceid_node * +__nfs4_find_get_deviceid(struct nfs_server *server, + const struct nfs4_deviceid *id, long hash) +{ + struct nfs4_deviceid_node *d; + + rcu_read_lock(); + d = _lookup_deviceid(server->pnfs_curr_ld, server->nfs_client, id, + hash); + if (d != NULL && !atomic_inc_not_zero(&d->ref)) + d = NULL; + rcu_read_unlock(); + return d; +} + +struct nfs4_deviceid_node * +nfs4_find_get_deviceid(struct nfs_server *server, + const struct nfs4_deviceid *id, const struct cred *cred, + gfp_t gfp_mask) +{ + long hash = nfs4_deviceid_hash(id); + struct nfs4_deviceid_node *d, *new; + + d = __nfs4_find_get_deviceid(server, id, hash); + if (d) + goto found; + + new = nfs4_get_device_info(server, id, cred, gfp_mask); + if (!new) { + trace_nfs4_find_deviceid(server, id, -ENOENT); + return new; + } + + spin_lock(&nfs4_deviceid_lock); + d = __nfs4_find_get_deviceid(server, id, hash); + if (d) { + spin_unlock(&nfs4_deviceid_lock); + server->pnfs_curr_ld->free_deviceid_node(new); + } else { + atomic_inc(&new->ref); + hlist_add_head_rcu(&new->node, &nfs4_deviceid_cache[hash]); + spin_unlock(&nfs4_deviceid_lock); + d = new; + } +found: + trace_nfs4_find_deviceid(server, id, 0); + return d; +} +EXPORT_SYMBOL_GPL(nfs4_find_get_deviceid); + +/* + * Remove a deviceid from cache + * + * @clp nfs_client associated with deviceid + * @id the deviceid to unhash + * + * @ret the unhashed node, if found and dereferenced to zero, NULL otherwise. + */ +void +nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *ld, + const struct nfs_client *clp, const struct nfs4_deviceid *id) +{ + struct nfs4_deviceid_node *d; + + spin_lock(&nfs4_deviceid_lock); + rcu_read_lock(); + d = _lookup_deviceid(ld, clp, id, nfs4_deviceid_hash(id)); + rcu_read_unlock(); + if (!d) { + spin_unlock(&nfs4_deviceid_lock); + return; + } + hlist_del_init_rcu(&d->node); + clear_bit(NFS_DEVICEID_NOCACHE, &d->flags); + spin_unlock(&nfs4_deviceid_lock); + + /* balance the initial ref set in pnfs_insert_deviceid */ + nfs4_put_deviceid_node(d); +} +EXPORT_SYMBOL_GPL(nfs4_delete_deviceid); + +void +nfs4_init_deviceid_node(struct nfs4_deviceid_node *d, struct nfs_server *server, + const struct nfs4_deviceid *id) +{ + INIT_HLIST_NODE(&d->node); + INIT_HLIST_NODE(&d->tmpnode); + d->ld = server->pnfs_curr_ld; + d->nfs_client = server->nfs_client; + d->flags = 0; + d->deviceid = *id; + atomic_set(&d->ref, 1); +} +EXPORT_SYMBOL_GPL(nfs4_init_deviceid_node); + +/* + * Dereference a deviceid node and delete it when its reference count drops + * to zero. + * + * @d deviceid node to put + * + * return true iff the node was deleted + * Note that since the test for d->ref == 0 is sufficient to establish + * that the node is no longer hashed in the global device id cache. + */ +bool +nfs4_put_deviceid_node(struct nfs4_deviceid_node *d) +{ + if (test_bit(NFS_DEVICEID_NOCACHE, &d->flags)) { + if (atomic_add_unless(&d->ref, -1, 2)) + return false; + nfs4_delete_deviceid(d->ld, d->nfs_client, &d->deviceid); + } + if (!atomic_dec_and_test(&d->ref)) + return false; + trace_nfs4_deviceid_free(d->nfs_client, &d->deviceid); + d->ld->free_deviceid_node(d); + return true; +} +EXPORT_SYMBOL_GPL(nfs4_put_deviceid_node); + +void +nfs4_mark_deviceid_available(struct nfs4_deviceid_node *node) +{ + if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) { + clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); + smp_mb__after_atomic(); + } +} +EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_available); + +void +nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node) +{ + node->timestamp_unavailable = jiffies; + smp_mb__before_atomic(); + set_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); + smp_mb__after_atomic(); +} +EXPORT_SYMBOL_GPL(nfs4_mark_deviceid_unavailable); + +bool +nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node) +{ + if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) { + unsigned long start, end; + + end = jiffies; + start = end - PNFS_DEVICE_RETRY_TIMEOUT; + if (time_in_range(node->timestamp_unavailable, start, end)) + return true; + clear_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags); + smp_mb__after_atomic(); + } + return false; +} +EXPORT_SYMBOL_GPL(nfs4_test_deviceid_unavailable); + +static void +_deviceid_purge_client(const struct nfs_client *clp, long hash) +{ + struct nfs4_deviceid_node *d; + HLIST_HEAD(tmp); + + spin_lock(&nfs4_deviceid_lock); + rcu_read_lock(); + hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[hash], node) + if (d->nfs_client == clp && atomic_read(&d->ref)) { + hlist_del_init_rcu(&d->node); + hlist_add_head(&d->tmpnode, &tmp); + clear_bit(NFS_DEVICEID_NOCACHE, &d->flags); + } + rcu_read_unlock(); + spin_unlock(&nfs4_deviceid_lock); + + if (hlist_empty(&tmp)) + return; + + while (!hlist_empty(&tmp)) { + d = hlist_entry(tmp.first, struct nfs4_deviceid_node, tmpnode); + hlist_del(&d->tmpnode); + nfs4_put_deviceid_node(d); + } +} + +void +nfs4_deviceid_purge_client(const struct nfs_client *clp) +{ + long h; + + if (!(clp->cl_exchange_flags & EXCHGID4_FLAG_USE_PNFS_MDS)) + return; + for (h = 0; h < NFS4_DEVICE_ID_HASH_SIZE; h++) + _deviceid_purge_client(clp, h); +} + +/* + * Stop use of all deviceids associated with an nfs_client + */ +void +nfs4_deviceid_mark_client_invalid(struct nfs_client *clp) +{ + struct nfs4_deviceid_node *d; + int i; + + rcu_read_lock(); + for (i = 0; i < NFS4_DEVICE_ID_HASH_SIZE; i ++){ + hlist_for_each_entry_rcu(d, &nfs4_deviceid_cache[i], node) + if (d->nfs_client == clp) + set_bit(NFS_DEVICEID_INVALID, &d->flags); + } + rcu_read_unlock(); +} -- cgit v1.3.1