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/lapb/lapb_out.c | 205 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+) create mode 100644 net/lapb/lapb_out.c (limited to 'net/lapb/lapb_out.c') diff --git a/net/lapb/lapb_out.c b/net/lapb/lapb_out.c new file mode 100644 index 000000000..a966d29c7 --- /dev/null +++ b/net/lapb/lapb_out.c @@ -0,0 +1,205 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naylor Started Coding + * LAPB 002 Jonathan Naylor New timer architecture. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * This procedure is passed a buffer descriptor for an iframe. It builds + * the rest of the control part of the frame and then writes it out. + */ +static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) +{ + unsigned char *frame; + + if (!skb) + return; + + if (lapb->mode & LAPB_EXTENDED) { + frame = skb_push(skb, 2); + + frame[0] = LAPB_I; + frame[0] |= lapb->vs << 1; + frame[1] = poll_bit ? LAPB_EPF : 0; + frame[1] |= lapb->vr << 1; + } else { + frame = skb_push(skb, 1); + + *frame = LAPB_I; + *frame |= poll_bit ? LAPB_SPF : 0; + *frame |= lapb->vr << 5; + *frame |= lapb->vs << 1; + } + + lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n", + lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); + + lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); +} + +void lapb_kick(struct lapb_cb *lapb) +{ + struct sk_buff *skb, *skbn; + unsigned short modulus, start, end; + + modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; + start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; + end = (lapb->va + lapb->window) % modulus; + + if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && + start != end && skb_peek(&lapb->write_queue)) { + lapb->vs = start; + + /* + * Dequeue the frame and copy it. + */ + skb = skb_dequeue(&lapb->write_queue); + + do { + skbn = skb_copy(skb, GFP_ATOMIC); + if (!skbn) { + skb_queue_head(&lapb->write_queue, skb); + break; + } + + if (skb->sk) + skb_set_owner_w(skbn, skb->sk); + + /* + * Transmit the frame copy. + */ + lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); + + lapb->vs = (lapb->vs + 1) % modulus; + + /* + * Requeue the original data frame. + */ + skb_queue_tail(&lapb->ack_queue, skb); + + } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); + + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; + + if (!lapb_t1timer_running(lapb)) + lapb_start_t1timer(lapb); + } +} + +void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) +{ + unsigned char *ptr; + + ptr = skb_push(skb, 1); + + if (lapb->mode & LAPB_MLP) { + if (lapb->mode & LAPB_DCE) { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_C; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_D; + } else { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_D; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_C; + } + } else { + if (lapb->mode & LAPB_DCE) { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_A; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_B; + } else { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_B; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_A; + } + } + + lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data); + + if (!lapb_data_transmit(lapb, skb)) + kfree_skb(skb); +} + +void lapb_establish_data_link(struct lapb_cb *lapb) +{ + lapb->condition = 0x00; + lapb->n2count = 0; + + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state); + lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); + } else { + lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state); + lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); + } + + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); +} + +void lapb_enquiry_response(struct lapb_cb *lapb) +{ + lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n", + lapb->dev, lapb->state, lapb->vr); + + lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); + + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; +} + +void lapb_timeout_response(struct lapb_cb *lapb) +{ + lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n", + lapb->dev, lapb->state, lapb->vr); + lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); + + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; +} + +void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) +{ + if (lapb->vs == nr) { + lapb_frames_acked(lapb, nr); + lapb_stop_t1timer(lapb); + lapb->n2count = 0; + } else if (lapb->va != nr) { + lapb_frames_acked(lapb, nr); + lapb_start_t1timer(lapb); + } +} + +void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) +{ + if (type == LAPB_COMMAND && pf) + lapb_enquiry_response(lapb); +} -- cgit v1.3.1