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 --- net/atm/proc.c | 333 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 333 insertions(+) create mode 100644 net/atm/proc.c (limited to 'net/atm/proc.c') diff --git a/net/atm/proc.c b/net/atm/proc.c new file mode 100644 index 000000000..8f20b49b9 --- /dev/null +++ b/net/atm/proc.c @@ -0,0 +1,333 @@ +// SPDX-License-Identifier: GPL-2.0 +/* net/atm/proc.c - ATM /proc interface + * + * Written 1995-2000 by Werner Almesberger, EPFL LRC/ICA + * + * seq_file api usage by romieu@fr.zoreil.com + * + * Evaluating the efficiency of the whole thing if left as an exercise to + * the reader. + */ + +#include /* for EXPORT_SYMBOL */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include /* for __init */ +#include +#include +#include +#include /* for HZ */ +#include +#include "resources.h" +#include "common.h" /* atm_proc_init prototype */ + +static ssize_t proc_dev_atm_read(struct file *file, char __user *buf, + size_t count, loff_t *pos); + +static const struct proc_ops atm_dev_proc_ops = { + .proc_read = proc_dev_atm_read, + .proc_lseek = noop_llseek, +}; + +static void add_stats(struct seq_file *seq, const char *aal, + const struct k_atm_aal_stats *stats) +{ + seq_printf(seq, "%s ( %d %d %d %d %d )", aal, + atomic_read(&stats->tx), atomic_read(&stats->tx_err), + atomic_read(&stats->rx), atomic_read(&stats->rx_err), + atomic_read(&stats->rx_drop)); +} + +static void atm_dev_info(struct seq_file *seq, const struct atm_dev *dev) +{ + int i; + + seq_printf(seq, "%3d %-8s", dev->number, dev->type); + for (i = 0; i < ESI_LEN; i++) + seq_printf(seq, "%02x", dev->esi[i]); + seq_puts(seq, " "); + add_stats(seq, "0", &dev->stats.aal0); + seq_puts(seq, " "); + add_stats(seq, "5", &dev->stats.aal5); + seq_printf(seq, "\t[%d]", refcount_read(&dev->refcnt)); + seq_putc(seq, '\n'); +} + +struct vcc_state { + int bucket; + struct sock *sk; +}; + +static inline int compare_family(struct sock *sk, int family) +{ + return !family || (sk->sk_family == family); +} + +static int __vcc_walk(struct sock **sock, int family, int *bucket, loff_t l) +{ + struct sock *sk = *sock; + + if (sk == SEQ_START_TOKEN) { + for (*bucket = 0; *bucket < VCC_HTABLE_SIZE; ++*bucket) { + struct hlist_head *head = &vcc_hash[*bucket]; + + sk = hlist_empty(head) ? NULL : __sk_head(head); + if (sk) + break; + } + l--; + } +try_again: + for (; sk; sk = sk_next(sk)) { + l -= compare_family(sk, family); + if (l < 0) + goto out; + } + if (!sk && ++*bucket < VCC_HTABLE_SIZE) { + sk = sk_head(&vcc_hash[*bucket]); + goto try_again; + } + sk = SEQ_START_TOKEN; +out: + *sock = sk; + return (l < 0); +} + +static inline void *vcc_walk(struct seq_file *seq, loff_t l) +{ + struct vcc_state *state = seq->private; + int family = (uintptr_t)(pde_data(file_inode(seq->file))); + + return __vcc_walk(&state->sk, family, &state->bucket, l) ? + state : NULL; +} + +static void *vcc_seq_start(struct seq_file *seq, loff_t *pos) + __acquires(vcc_sklist_lock) +{ + struct vcc_state *state = seq->private; + loff_t left = *pos; + + read_lock(&vcc_sklist_lock); + state->sk = SEQ_START_TOKEN; + return left ? vcc_walk(seq, left) : SEQ_START_TOKEN; +} + +static void vcc_seq_stop(struct seq_file *seq, void *v) + __releases(vcc_sklist_lock) +{ + read_unlock(&vcc_sklist_lock); +} + +static void *vcc_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + v = vcc_walk(seq, 1); + (*pos)++; + return v; +} + +static void pvc_info(struct seq_file *seq, struct atm_vcc *vcc) +{ + static const char *const class_name[] = { + "off", "UBR", "CBR", "VBR", "ABR"}; + static const char *const aal_name[] = { + "---", "1", "2", "3/4", /* 0- 3 */ + "???", "5", "???", "???", /* 4- 7 */ + "???", "???", "???", "???", /* 8-11 */ + "???", "0", "???", "???"}; /* 12-15 */ + + seq_printf(seq, "%3d %3d %5d %-3s %7d %-5s %7d %-6s", + vcc->dev->number, vcc->vpi, vcc->vci, + vcc->qos.aal >= ARRAY_SIZE(aal_name) ? "err" : + aal_name[vcc->qos.aal], vcc->qos.rxtp.min_pcr, + class_name[vcc->qos.rxtp.traffic_class], + vcc->qos.txtp.min_pcr, + class_name[vcc->qos.txtp.traffic_class]); + seq_putc(seq, '\n'); +} + +static void vcc_info(struct seq_file *seq, struct atm_vcc *vcc) +{ + struct sock *sk = sk_atm(vcc); + + seq_printf(seq, "%pK ", vcc); + if (!vcc->dev) + seq_printf(seq, "Unassigned "); + else + seq_printf(seq, "%3d %3d %5d ", vcc->dev->number, vcc->vpi, + vcc->vci); + switch (sk->sk_family) { + case AF_ATMPVC: + seq_printf(seq, "PVC"); + break; + default: + seq_printf(seq, "%3d", sk->sk_family); + } + seq_printf(seq, " %04lx %5d %7d/%7d %7d/%7d [%d]\n", + vcc->flags, sk->sk_err, + sk_wmem_alloc_get(sk), sk->sk_sndbuf, + sk_rmem_alloc_get(sk), sk->sk_rcvbuf, + refcount_read(&sk->sk_refcnt)); +} + +static int atm_dev_seq_show(struct seq_file *seq, void *v) +{ + static char atm_dev_banner[] = + "Itf Type ESI/\"MAC\"addr " + "AAL(TX,err,RX,err,drop) ... [refcnt]\n"; + + if (v == &atm_devs) + seq_puts(seq, atm_dev_banner); + else { + struct atm_dev *dev = list_entry(v, struct atm_dev, dev_list); + + atm_dev_info(seq, dev); + } + return 0; +} + +static const struct seq_operations atm_dev_seq_ops = { + .start = atm_dev_seq_start, + .next = atm_dev_seq_next, + .stop = atm_dev_seq_stop, + .show = atm_dev_seq_show, +}; + +static int pvc_seq_show(struct seq_file *seq, void *v) +{ + static char atm_pvc_banner[] = + "Itf VPI VCI AAL RX(PCR,Class) TX(PCR,Class)\n"; + + if (v == SEQ_START_TOKEN) + seq_puts(seq, atm_pvc_banner); + else { + struct vcc_state *state = seq->private; + struct atm_vcc *vcc = atm_sk(state->sk); + + pvc_info(seq, vcc); + } + return 0; +} + +static const struct seq_operations pvc_seq_ops = { + .start = vcc_seq_start, + .next = vcc_seq_next, + .stop = vcc_seq_stop, + .show = pvc_seq_show, +}; + +static int vcc_seq_show(struct seq_file *seq, void *v) +{ + if (v == SEQ_START_TOKEN) { + seq_printf(seq, sizeof(void *) == 4 ? "%-8s%s" : "%-16s%s", + "Address ", "Itf VPI VCI Fam Flags Reply " + "Send buffer Recv buffer [refcnt]\n"); + } else { + struct vcc_state *state = seq->private; + struct atm_vcc *vcc = atm_sk(state->sk); + + vcc_info(seq, vcc); + } + return 0; +} + +static const struct seq_operations vcc_seq_ops = { + .start = vcc_seq_start, + .next = vcc_seq_next, + .stop = vcc_seq_stop, + .show = vcc_seq_show, +}; + +static ssize_t proc_dev_atm_read(struct file *file, char __user *buf, + size_t count, loff_t *pos) +{ + struct atm_dev *dev; + unsigned long page; + int length; + + if (count == 0) + return 0; + page = get_zeroed_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + dev = pde_data(file_inode(file)); + if (!dev->ops->proc_read) + length = -EINVAL; + else { + length = dev->ops->proc_read(dev, pos, (char *)page); + if (length > count) + length = -EINVAL; + } + if (length >= 0) { + if (copy_to_user(buf, (char *)page, length)) + length = -EFAULT; + (*pos)++; + } + free_page(page); + return length; +} + +struct proc_dir_entry *atm_proc_root; +EXPORT_SYMBOL(atm_proc_root); + + +int atm_proc_dev_register(struct atm_dev *dev) +{ + int error; + + /* No proc info */ + if (!dev->ops->proc_read) + return 0; + + error = -ENOMEM; + dev->proc_name = kasprintf(GFP_KERNEL, "%s:%d", dev->type, dev->number); + if (!dev->proc_name) + goto err_out; + + dev->proc_entry = proc_create_data(dev->proc_name, 0, atm_proc_root, + &atm_dev_proc_ops, dev); + if (!dev->proc_entry) + goto err_free_name; + return 0; + +err_free_name: + kfree(dev->proc_name); +err_out: + return error; +} + +void atm_proc_dev_deregister(struct atm_dev *dev) +{ + if (!dev->ops->proc_read) + return; + + remove_proc_entry(dev->proc_name, atm_proc_root); + kfree(dev->proc_name); +} + +int __init atm_proc_init(void) +{ + atm_proc_root = proc_net_mkdir(&init_net, "atm", init_net.proc_net); + if (!atm_proc_root) + return -ENOMEM; + proc_create_seq("devices", 0444, atm_proc_root, &atm_dev_seq_ops); + proc_create_seq_private("pvc", 0444, atm_proc_root, &pvc_seq_ops, + sizeof(struct vcc_state), (void *)(uintptr_t)PF_ATMPVC); + proc_create_seq_private("vc", 0444, atm_proc_root, &vcc_seq_ops, + sizeof(struct vcc_state), NULL); + return 0; +} + +void atm_proc_exit(void) +{ + remove_proc_subtree("atm", init_net.proc_net); +} -- cgit v1.3.1