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/llc/llc_output.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 net/llc/llc_output.c (limited to 'net/llc/llc_output.c') diff --git a/net/llc/llc_output.c b/net/llc/llc_output.c new file mode 100644 index 000000000..5a6466fc6 --- /dev/null +++ b/net/llc/llc_output.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * llc_output.c - LLC minimal output path + * + * Copyright (c) 1997 by Procom Technology, Inc. + * 2001-2003 by Arnaldo Carvalho de Melo + */ + +#include +#include +#include +#include +#include +#include + +/** + * llc_mac_hdr_init - fills MAC header fields + * @skb: Address of the frame to initialize its MAC header + * @sa: The MAC source address + * @da: The MAC destination address + * + * Fills MAC header fields, depending on MAC type. Returns 0, If MAC type + * is a valid type and initialization completes correctly 1, otherwise. + */ +int llc_mac_hdr_init(struct sk_buff *skb, + const unsigned char *sa, const unsigned char *da) +{ + int rc = -EINVAL; + + switch (skb->dev->type) { + case ARPHRD_ETHER: + case ARPHRD_LOOPBACK: + rc = dev_hard_header(skb, skb->dev, ETH_P_802_2, da, sa, + skb->len); + if (rc > 0) + rc = 0; + break; + default: + break; + } + return rc; +} + +/** + * llc_build_and_send_ui_pkt - unitdata request interface for upper layers + * @sap: sap to use + * @skb: packet to send + * @dmac: destination mac address + * @dsap: destination sap + * + * Upper layers calls this function when upper layer wants to send data + * using connection-less mode communication (UI pdu). + * + * Accept data frame from network layer to be sent using connection- + * less mode communication; timeout/retries handled by network layer; + * package primitive as an event and send to SAP event handler + */ +int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb, + const unsigned char *dmac, unsigned char dsap) +{ + int rc; + llc_pdu_header_init(skb, LLC_PDU_TYPE_U, sap->laddr.lsap, + dsap, LLC_PDU_CMD); + llc_pdu_init_as_ui_cmd(skb); + rc = llc_mac_hdr_init(skb, skb->dev->dev_addr, dmac); + if (likely(!rc)) + rc = dev_queue_xmit(skb); + else + kfree_skb(skb); + return rc; +} + +EXPORT_SYMBOL(llc_mac_hdr_init); +EXPORT_SYMBOL(llc_build_and_send_ui_pkt); -- cgit v1.3.1