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 --- include/asm-generic/barrier.h | 306 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 306 insertions(+) create mode 100644 include/asm-generic/barrier.h (limited to 'include/asm-generic/barrier.h') diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h new file mode 100644 index 000000000..b99cb57df --- /dev/null +++ b/include/asm-generic/barrier.h @@ -0,0 +1,306 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Generic barrier definitions. + * + * It should be possible to use these on really simple architectures, + * but it serves more as a starting point for new ports. + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ +#ifndef __ASM_GENERIC_BARRIER_H +#define __ASM_GENERIC_BARRIER_H + +#ifndef __ASSEMBLY__ + +#include +#include +#include + +#ifndef nop +#define nop() asm volatile ("nop") +#endif + +/* + * Architectures that want generic instrumentation can define __ prefixed + * variants of all barriers. + */ + +#ifdef __mb +#define mb() do { kcsan_mb(); __mb(); } while (0) +#endif + +#ifdef __rmb +#define rmb() do { kcsan_rmb(); __rmb(); } while (0) +#endif + +#ifdef __wmb +#define wmb() do { kcsan_wmb(); __wmb(); } while (0) +#endif + +#ifdef __dma_mb +#define dma_mb() do { kcsan_mb(); __dma_mb(); } while (0) +#endif + +#ifdef __dma_rmb +#define dma_rmb() do { kcsan_rmb(); __dma_rmb(); } while (0) +#endif + +#ifdef __dma_wmb +#define dma_wmb() do { kcsan_wmb(); __dma_wmb(); } while (0) +#endif + +/* + * Force strict CPU ordering. And yes, this is required on UP too when we're + * talking to devices. + * + * Fall back to compiler barriers if nothing better is provided. + */ + +#ifndef mb +#define mb() barrier() +#endif + +#ifndef rmb +#define rmb() mb() +#endif + +#ifndef wmb +#define wmb() mb() +#endif + +#ifndef dma_mb +#define dma_mb() mb() +#endif + +#ifndef dma_rmb +#define dma_rmb() rmb() +#endif + +#ifndef dma_wmb +#define dma_wmb() wmb() +#endif + +#ifndef __smp_mb +#define __smp_mb() mb() +#endif + +#ifndef __smp_rmb +#define __smp_rmb() rmb() +#endif + +#ifndef __smp_wmb +#define __smp_wmb() wmb() +#endif + +#ifdef CONFIG_SMP + +#ifndef smp_mb +#define smp_mb() do { kcsan_mb(); __smp_mb(); } while (0) +#endif + +#ifndef smp_rmb +#define smp_rmb() do { kcsan_rmb(); __smp_rmb(); } while (0) +#endif + +#ifndef smp_wmb +#define smp_wmb() do { kcsan_wmb(); __smp_wmb(); } while (0) +#endif + +#else /* !CONFIG_SMP */ + +#ifndef smp_mb +#define smp_mb() barrier() +#endif + +#ifndef smp_rmb +#define smp_rmb() barrier() +#endif + +#ifndef smp_wmb +#define smp_wmb() barrier() +#endif + +#endif /* CONFIG_SMP */ + +#ifndef __smp_store_mb +#define __smp_store_mb(var, value) do { WRITE_ONCE(var, value); __smp_mb(); } while (0) +#endif + +#ifndef __smp_mb__before_atomic +#define __smp_mb__before_atomic() __smp_mb() +#endif + +#ifndef __smp_mb__after_atomic +#define __smp_mb__after_atomic() __smp_mb() +#endif + +#ifndef __smp_store_release +#define __smp_store_release(p, v) \ +do { \ + compiletime_assert_atomic_type(*p); \ + __smp_mb(); \ + WRITE_ONCE(*p, v); \ +} while (0) +#endif + +#ifndef __smp_load_acquire +#define __smp_load_acquire(p) \ +({ \ + __unqual_scalar_typeof(*p) ___p1 = READ_ONCE(*p); \ + compiletime_assert_atomic_type(*p); \ + __smp_mb(); \ + (typeof(*p))___p1; \ +}) +#endif + +#ifdef CONFIG_SMP + +#ifndef smp_store_mb +#define smp_store_mb(var, value) do { kcsan_mb(); __smp_store_mb(var, value); } while (0) +#endif + +#ifndef smp_mb__before_atomic +#define smp_mb__before_atomic() do { kcsan_mb(); __smp_mb__before_atomic(); } while (0) +#endif + +#ifndef smp_mb__after_atomic +#define smp_mb__after_atomic() do { kcsan_mb(); __smp_mb__after_atomic(); } while (0) +#endif + +#ifndef smp_store_release +#define smp_store_release(p, v) do { kcsan_release(); __smp_store_release(p, v); } while (0) +#endif + +#ifndef smp_load_acquire +#define smp_load_acquire(p) __smp_load_acquire(p) +#endif + +#else /* !CONFIG_SMP */ + +#ifndef smp_store_mb +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); barrier(); } while (0) +#endif + +#ifndef smp_mb__before_atomic +#define smp_mb__before_atomic() barrier() +#endif + +#ifndef smp_mb__after_atomic +#define smp_mb__after_atomic() barrier() +#endif + +#ifndef smp_store_release +#define smp_store_release(p, v) \ +do { \ + barrier(); \ + WRITE_ONCE(*p, v); \ +} while (0) +#endif + +#ifndef smp_load_acquire +#define smp_load_acquire(p) \ +({ \ + __unqual_scalar_typeof(*p) ___p1 = READ_ONCE(*p); \ + barrier(); \ + (typeof(*p))___p1; \ +}) +#endif + +#endif /* CONFIG_SMP */ + +/* Barriers for virtual machine guests when talking to an SMP host */ +#define virt_mb() do { kcsan_mb(); __smp_mb(); } while (0) +#define virt_rmb() do { kcsan_rmb(); __smp_rmb(); } while (0) +#define virt_wmb() do { kcsan_wmb(); __smp_wmb(); } while (0) +#define virt_store_mb(var, value) do { kcsan_mb(); __smp_store_mb(var, value); } while (0) +#define virt_mb__before_atomic() do { kcsan_mb(); __smp_mb__before_atomic(); } while (0) +#define virt_mb__after_atomic() do { kcsan_mb(); __smp_mb__after_atomic(); } while (0) +#define virt_store_release(p, v) do { kcsan_release(); __smp_store_release(p, v); } while (0) +#define virt_load_acquire(p) __smp_load_acquire(p) + +/** + * smp_acquire__after_ctrl_dep() - Provide ACQUIRE ordering after a control dependency + * + * A control dependency provides a LOAD->STORE order, the additional RMB + * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order, + * aka. (load)-ACQUIRE. + * + * Architectures that do not do load speculation can have this be barrier(). + */ +#ifndef smp_acquire__after_ctrl_dep +#define smp_acquire__after_ctrl_dep() smp_rmb() +#endif + +/** + * smp_cond_load_relaxed() - (Spin) wait for cond with no ordering guarantees + * @ptr: pointer to the variable to wait on + * @cond_expr: boolean expression to wait for + * + * Equivalent to using READ_ONCE() on the condition variable. + * + * Due to C lacking lambda expressions we load the value of *ptr into a + * pre-named variable @VAL to be used in @cond. + */ +#ifndef smp_cond_load_relaxed +#define smp_cond_load_relaxed(ptr, cond_expr) ({ \ + typeof(ptr) __PTR = (ptr); \ + __unqual_scalar_typeof(*ptr) VAL; \ + for (;;) { \ + VAL = READ_ONCE(*__PTR); \ + if (cond_expr) \ + break; \ + cpu_relax(); \ + } \ + (typeof(*ptr))VAL; \ +}) +#endif + +/** + * smp_cond_load_acquire() - (Spin) wait for cond with ACQUIRE ordering + * @ptr: pointer to the variable to wait on + * @cond_expr: boolean expression to wait for + * + * Equivalent to using smp_load_acquire() on the condition variable but employs + * the control dependency of the wait to reduce the barrier on many platforms. + */ +#ifndef smp_cond_load_acquire +#define smp_cond_load_acquire(ptr, cond_expr) ({ \ + __unqual_scalar_typeof(*ptr) _val; \ + _val = smp_cond_load_relaxed(ptr, cond_expr); \ + smp_acquire__after_ctrl_dep(); \ + (typeof(*ptr))_val; \ +}) +#endif + +/* + * pmem_wmb() ensures that all stores for which the modification + * are written to persistent storage by preceding instructions have + * updated persistent storage before any data access or data transfer + * caused by subsequent instructions is initiated. + */ +#ifndef pmem_wmb +#define pmem_wmb() wmb() +#endif + +/* + * ioremap_wc() maps I/O memory as memory with write-combining attributes. For + * this kind of memory accesses, the CPU may wait for prior accesses to be + * merged with subsequent ones. In some situation, such wait is bad for the + * performance. io_stop_wc() can be used to prevent the merging of + * write-combining memory accesses before this macro with those after it. + */ +#ifndef io_stop_wc +#define io_stop_wc() do { } while (0) +#endif + +/* + * Architectures that guarantee an implicit smp_mb() in switch_mm() + * can override smp_mb__after_switch_mm. + */ +#ifndef smp_mb__after_switch_mm +# define smp_mb__after_switch_mm() smp_mb() +#endif + +#endif /* !__ASSEMBLY__ */ +#endif /* __ASM_GENERIC_BARRIER_H */ -- cgit v1.3.1