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 --- drivers/dibs/dibs_loopback.h | 57 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 drivers/dibs/dibs_loopback.h (limited to 'drivers/dibs/dibs_loopback.h') diff --git a/drivers/dibs/dibs_loopback.h b/drivers/dibs/dibs_loopback.h new file mode 100644 index 000000000..0664f6a8e --- /dev/null +++ b/drivers/dibs/dibs_loopback.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * dibs loopback (aka loopback-ism) device structure definitions. + * + * Copyright (c) 2024, Alibaba Inc. + * + * Author: Wen Gu + * Tony Lu + * + */ + +#ifndef _DIBS_LOOPBACK_H +#define _DIBS_LOOPBACK_H + +#include +#include +#include +#include +#include + +#if IS_ENABLED(CONFIG_DIBS_LO) +#define DIBS_LO_DMBS_HASH_BITS 12 +#define DIBS_LO_MAX_DMBS 5000 + +struct dibs_lo_dmb_node { + struct hlist_node list; + u64 token; + u32 len; + u32 sba_idx; + void *cpu_addr; + dma_addr_t dma_addr; + refcount_t refcnt; +}; + +struct dibs_lo_dev { + struct dibs_dev *dibs; + atomic_t dmb_cnt; + rwlock_t dmb_ht_lock; + DECLARE_BITMAP(sba_idx_mask, DIBS_LO_MAX_DMBS); + DECLARE_HASHTABLE(dmb_ht, DIBS_LO_DMBS_HASH_BITS); + wait_queue_head_t ldev_release; +}; + +int dibs_loopback_init(void); +void dibs_loopback_exit(void); +#else +static inline int dibs_loopback_init(void) +{ + return 0; +} + +static inline void dibs_loopback_exit(void) +{ +} +#endif + +#endif /* _DIBS_LOOPBACK_H */ -- cgit v1.3.1