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/md/dm-pcache/segment.h | 74 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 drivers/md/dm-pcache/segment.h (limited to 'drivers/md/dm-pcache/segment.h') diff --git a/drivers/md/dm-pcache/segment.h b/drivers/md/dm-pcache/segment.h new file mode 100644 index 000000000..deca1ddcb --- /dev/null +++ b/drivers/md/dm-pcache/segment.h @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _PCACHE_SEGMENT_H +#define _PCACHE_SEGMENT_H + +#include +#include + +#include "pcache_internal.h" + +struct pcache_segment_info { + struct pcache_meta_header header; + __u32 flags; + __u32 next_seg; +}; + +#define PCACHE_SEG_INFO_FLAGS_HAS_NEXT BIT(0) + +#define PCACHE_SEG_INFO_FLAGS_TYPE_MASK GENMASK(4, 1) +#define PCACHE_SEGMENT_TYPE_CACHE_DATA 1 + +static inline bool segment_info_has_next(struct pcache_segment_info *seg_info) +{ + return (seg_info->flags & PCACHE_SEG_INFO_FLAGS_HAS_NEXT); +} + +static inline void segment_info_set_type(struct pcache_segment_info *seg_info, u8 type) +{ + seg_info->flags &= ~PCACHE_SEG_INFO_FLAGS_TYPE_MASK; + seg_info->flags |= FIELD_PREP(PCACHE_SEG_INFO_FLAGS_TYPE_MASK, type); +} + +static inline u8 segment_info_get_type(struct pcache_segment_info *seg_info) +{ + return FIELD_GET(PCACHE_SEG_INFO_FLAGS_TYPE_MASK, seg_info->flags); +} + +struct pcache_segment_pos { + struct pcache_segment *segment; /* Segment associated with the position */ + u32 off; /* Offset within the segment */ +}; + +struct pcache_segment_init_options { + u8 type; + u32 seg_id; + u32 data_off; + + struct pcache_segment_info *seg_info; +}; + +struct pcache_segment { + struct pcache_cache_dev *cache_dev; + + void *data; + u32 data_size; + u32 seg_id; + + struct pcache_segment_info *seg_info; +}; + +int segment_copy_to_bio(struct pcache_segment *segment, + u32 data_off, u32 data_len, struct bio *bio, u32 bio_off); +int segment_copy_from_bio(struct pcache_segment *segment, + u32 data_off, u32 data_len, struct bio *bio, u32 bio_off); + +static inline void segment_pos_advance(struct pcache_segment_pos *seg_pos, u32 len) +{ + BUG_ON(seg_pos->off + len > seg_pos->segment->data_size); + + seg_pos->off += len; +} + +void pcache_segment_init(struct pcache_cache_dev *cache_dev, struct pcache_segment *segment, + struct pcache_segment_init_options *options); +#endif /* _PCACHE_SEGMENT_H */ -- cgit v1.3.1