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 --- arch/m68k/atari/stram.c | 202 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 202 insertions(+) create mode 100644 arch/m68k/atari/stram.c (limited to 'arch/m68k/atari/stram.c') diff --git a/arch/m68k/atari/stram.c b/arch/m68k/atari/stram.c new file mode 100644 index 000000000..82b31321f --- /dev/null +++ b/arch/m68k/atari/stram.c @@ -0,0 +1,202 @@ +/* + * Functions for ST-RAM allocations + * + * Copyright 1994-97 Roman Hodek + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + + +/* + * The ST-RAM allocator allocates memory from a pool of reserved ST-RAM of + * configurable size, set aside on ST-RAM init. + * As long as this pool is not exhausted, allocation of real ST-RAM can be + * guaranteed. + */ + +/* set if kernel is in ST-RAM */ +static int kernel_in_stram; + +static struct resource stram_pool = { + .name = "ST-RAM Pool" +}; + +static unsigned long pool_size = 1024*1024; + +static unsigned long stram_virt_offset; + +static int __init atari_stram_setup(char *arg) +{ + if (!MACH_IS_ATARI) + return 0; + + pool_size = memparse(arg, NULL); + return 0; +} + +early_param("stram_pool", atari_stram_setup); + + +/* + * This init function is called very early by atari/config.c + * It initializes some internal variables needed for stram_alloc() + */ +void __init atari_stram_init(void) +{ + int i; + + /* + * determine whether kernel code resides in ST-RAM + * (then ST-RAM is the first memory block at virtual 0x0) + */ + kernel_in_stram = (m68k_memory[0].addr == 0); + + for (i = 0; i < m68k_num_memory; ++i) { + if (m68k_memory[i].addr == 0) { + return; + } + } + + /* Should never come here! (There is always ST-Ram!) */ + panic("atari_stram_init: no ST-RAM found!"); +} + + +/* + * This function is called from setup_arch() to reserve the pages needed for + * ST-RAM management, if the kernel resides in ST-RAM. + */ +void __init atari_stram_reserve_pages(void *start_mem) +{ + if (kernel_in_stram) { + pr_debug("atari_stram pool: kernel in ST-RAM, using alloc_bootmem!\n"); + stram_pool.start = (resource_size_t)memblock_alloc_low(pool_size, + PAGE_SIZE); + if (!stram_pool.start) + panic("%s: Failed to allocate %lu bytes align=%lx\n", + __func__, pool_size, PAGE_SIZE); + + stram_pool.end = stram_pool.start + pool_size - 1; + request_resource(&iomem_resource, &stram_pool); + stram_virt_offset = 0; + pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n", + pool_size, &stram_pool); + pr_debug("atari_stram pool: stram_virt_offset = %lx\n", + stram_virt_offset); + } +} + + +/* + * This function is called as arch initcall to reserve the pages needed for + * ST-RAM management, if the kernel does not reside in ST-RAM. + */ +static int __init atari_stram_map_pages(void) +{ + if (!kernel_in_stram) { + /* + * Skip page 0, as the fhe first 2 KiB are supervisor-only! + */ + pr_debug("atari_stram pool: kernel not in ST-RAM, using ioremap!\n"); + stram_pool.start = PAGE_SIZE; + stram_pool.end = stram_pool.start + pool_size - 1; + request_resource(&iomem_resource, &stram_pool); + stram_virt_offset = (unsigned long) ioremap(stram_pool.start, + resource_size(&stram_pool)) - stram_pool.start; + pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n", + pool_size, &stram_pool); + pr_debug("atari_stram pool: stram_virt_offset = %lx\n", + stram_virt_offset); + } + return 0; +} +arch_initcall(atari_stram_map_pages); + + +void *atari_stram_to_virt(unsigned long phys) +{ + return (void *)(phys + stram_virt_offset); +} +EXPORT_SYMBOL(atari_stram_to_virt); + + +unsigned long atari_stram_to_phys(void *virt) +{ + return (unsigned long)(virt - stram_virt_offset); +} +EXPORT_SYMBOL(atari_stram_to_phys); + + +void *atari_stram_alloc(unsigned long size, const char *owner) +{ + struct resource *res; + int error; + + pr_debug("atari_stram_alloc: allocate %lu bytes\n", size); + + /* round up */ + size = PAGE_ALIGN(size); + + res = kzalloc_obj(struct resource); + if (!res) + return NULL; + + res->name = owner; + error = allocate_resource(&stram_pool, res, size, 0, UINT_MAX, + PAGE_SIZE, NULL, NULL); + if (error < 0) { + pr_err("atari_stram_alloc: allocate_resource() failed %d!\n", + error); + kfree(res); + return NULL; + } + + pr_debug("atari_stram_alloc: returning %pR\n", res); + return atari_stram_to_virt(res->start); +} +EXPORT_SYMBOL(atari_stram_alloc); + + +void atari_stram_free(void *addr) +{ + unsigned long start = atari_stram_to_phys(addr); + struct resource *res; + unsigned long size; + + res = lookup_resource(&stram_pool, start); + if (!res) { + pr_err("atari_stram_free: trying to free nonexistent region " + "at %p\n", addr); + return; + } + + size = resource_size(res); + pr_debug("atari_stram_free: free %lu bytes at %p\n", size, addr); + release_resource(res); + kfree(res); +} +EXPORT_SYMBOL(atari_stram_free); -- cgit v1.3.1