From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/scsi/arm/msgqueue.h | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 drivers/scsi/arm/msgqueue.h (limited to 'drivers/scsi/arm/msgqueue.h') diff --git a/drivers/scsi/arm/msgqueue.h b/drivers/scsi/arm/msgqueue.h new file mode 100644 index 000000000..4bcc400f5 --- /dev/null +++ b/drivers/scsi/arm/msgqueue.h @@ -0,0 +1,79 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * linux/drivers/acorn/scsi/msgqueue.h + * + * Copyright (C) 1997 Russell King + * + * message queue handling + */ +#ifndef MSGQUEUE_H +#define MSGQUEUE_H + +struct message { + char msg[8]; + int length; + int fifo; +}; + +struct msgqueue_entry { + struct message msg; + struct msgqueue_entry *next; +}; + +#define NR_MESSAGES 4 + +typedef struct { + struct msgqueue_entry *qe; + struct msgqueue_entry *free; + struct msgqueue_entry entries[NR_MESSAGES]; +} MsgQueue_t; + +/* + * Function: void msgqueue_initialise(MsgQueue_t *msgq) + * Purpose : initialise a message queue + * Params : msgq - queue to initialise + */ +extern void msgqueue_initialise(MsgQueue_t *msgq); + +/* + * Function: void msgqueue_free(MsgQueue_t *msgq) + * Purpose : free a queue + * Params : msgq - queue to free + */ +extern void msgqueue_free(MsgQueue_t *msgq); + +/* + * Function: int msgqueue_msglength(MsgQueue_t *msgq) + * Purpose : calculate the total length of all messages on the message queue + * Params : msgq - queue to examine + * Returns : number of bytes of messages in queue + */ +extern int msgqueue_msglength(MsgQueue_t *msgq); + +/* + * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) + * Purpose : return a message & its length + * Params : msgq - queue to obtain message from + * : msgno - message number + * Returns : pointer to message string, or NULL + */ +extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno); + +/* + * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) + * Purpose : add a message onto a message queue + * Params : msgq - queue to add message on + * length - length of message + * ... - message bytes + * Returns : != 0 if successful + */ +extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...); + +/* + * Function: void msgqueue_flush(MsgQueue_t *msgq) + * Purpose : flush all messages from message queue + * Params : msgq - queue to flush + */ +extern void msgqueue_flush(MsgQueue_t *msgq); + +#endif -- cgit v1.3.1