From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- drivers/md/persistent-data/dm-block-manager.h | 138 ++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 drivers/md/persistent-data/dm-block-manager.h (limited to 'drivers/md/persistent-data/dm-block-manager.h') diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h new file mode 100644 index 000000000..b19989685 --- /dev/null +++ b/drivers/md/persistent-data/dm-block-manager.h @@ -0,0 +1,138 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2011 Red Hat, Inc. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_BLOCK_MANAGER_H +#define _LINUX_DM_BLOCK_MANAGER_H + +#include +#include + +/*----------------------------------------------------------------*/ + +/* + * Block number. + */ +typedef uint64_t dm_block_t; +struct dm_block; + +dm_block_t dm_block_location(struct dm_block *b); +void *dm_block_data(struct dm_block *b); + +/*----------------------------------------------------------------*/ + +/* + * @name should be a unique identifier for the block manager, no longer + * than 32 chars. + * + * @max_held_per_thread should be the maximum number of locks, read or + * write, that an individual thread holds at any one time. + */ +struct dm_block_manager; +struct dm_block_manager *dm_block_manager_create( + struct block_device *bdev, unsigned int block_size, + unsigned int max_held_per_thread); +void dm_block_manager_destroy(struct dm_block_manager *bm); +void dm_block_manager_reset(struct dm_block_manager *bm); + +unsigned int dm_bm_block_size(struct dm_block_manager *bm); +dm_block_t dm_bm_nr_blocks(struct dm_block_manager *bm); + +/*----------------------------------------------------------------*/ + +/* + * The validator allows the caller to verify newly-read data and modify + * the data just before writing, e.g. to calculate checksums. It's + * important to be consistent with your use of validators. The only time + * you can change validators is if you call dm_bm_write_lock_zero. + */ +struct dm_block_validator { + const char *name; + void (*prepare_for_write)(const struct dm_block_validator *v, + struct dm_block *b, size_t block_size); + + /* + * Return 0 if the checksum is valid or < 0 on error. + */ + int (*check)(const struct dm_block_validator *v, + struct dm_block *b, size_t block_size); +}; + +/*----------------------------------------------------------------*/ + +/* + * You can have multiple concurrent readers or a single writer holding a + * block lock. + */ + +/* + * dm_bm_lock() locks a block and returns through @result a pointer to + * memory that holds a copy of that block. If you have write-locked the + * block then any changes you make to memory pointed to by @result will be + * written back to the disk sometime after dm_bm_unlock is called. + */ +int dm_bm_read_lock(struct dm_block_manager *bm, dm_block_t b, + const struct dm_block_validator *v, + struct dm_block **result); + +int dm_bm_write_lock(struct dm_block_manager *bm, dm_block_t b, + const struct dm_block_validator *v, + struct dm_block **result); + +/* + * The *_try_lock variants return -EWOULDBLOCK if the block isn't + * available immediately. + */ +int dm_bm_read_try_lock(struct dm_block_manager *bm, dm_block_t b, + const struct dm_block_validator *v, + struct dm_block **result); + +/* + * Use dm_bm_write_lock_zero() when you know you're going to + * overwrite the block completely. It saves a disk read. + */ +int dm_bm_write_lock_zero(struct dm_block_manager *bm, dm_block_t b, + const struct dm_block_validator *v, + struct dm_block **result); + +void dm_bm_unlock(struct dm_block *b); + +/* + * It's a common idiom to have a superblock that should be committed last. + * + * @superblock should be write-locked on entry. It will be unlocked during + * this function. All dirty blocks are guaranteed to be written and flushed + * before the superblock. + * + * This method always blocks. + */ +int dm_bm_flush(struct dm_block_manager *bm); + +/* + * Request data is prefetched into the cache. + */ +void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b); + +/* + * Switches the bm to a read only mode. Once read-only mode + * has been entered the following functions will return -EPERM. + * + * dm_bm_write_lock + * dm_bm_write_lock_zero + * dm_bm_flush_and_unlock + * + * Additionally you should not use dm_bm_unlock_move, however no error will + * be returned if you do. + */ +bool dm_bm_is_read_only(struct dm_block_manager *bm); +void dm_bm_set_read_only(struct dm_block_manager *bm); +void dm_bm_set_read_write(struct dm_block_manager *bm); + +u32 dm_bm_checksum(const void *data, size_t len, u32 init_xor); + +/*----------------------------------------------------------------*/ + +#endif /* _LINUX_DM_BLOCK_MANAGER_H */ -- cgit v1.3.1