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/firmware/efi/memmap.c | 148 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 drivers/firmware/efi/memmap.c (limited to 'drivers/firmware/efi/memmap.c') diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c new file mode 100644 index 000000000..f1c04d7cf --- /dev/null +++ b/drivers/firmware/efi/memmap.c @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Common EFI memory map functions. + */ + +#define pr_fmt(fmt) "efi: " fmt + +#include +#include +#include +#include +#include +#include + +#include +#include + +/** + * __efi_memmap_init - Common code for mapping the EFI memory map + * @data: EFI memory map data + * + * This function takes care of figuring out which function to use to + * map the EFI memory map in efi.memmap based on how far into the boot + * we are. + * + * During bootup EFI_MEMMAP_LATE in data->flags should be clear since we + * only have access to the early_memremap*() functions as the vmalloc + * space isn't setup. Once the kernel is fully booted we can fallback + * to the more robust memremap*() API. + * + * Returns: zero on success, a negative error code on failure. + */ +int __init __efi_memmap_init(struct efi_memory_map_data *data) +{ + struct efi_memory_map map; + phys_addr_t phys_map; + + phys_map = data->phys_map; + + if (data->flags & EFI_MEMMAP_LATE) + map.map = memremap(phys_map, data->size, MEMREMAP_WB); + else + map.map = early_memremap(phys_map, data->size); + + if (!map.map) { + pr_err("Could not map the memory map! phys_map=%pa, size=0x%lx\n", + &phys_map, data->size); + return -ENOMEM; + } + + map.phys_map = data->phys_map; + map.nr_map = data->size / data->desc_size; + map.map_end = map.map + data->size; + + map.desc_version = data->desc_version; + map.desc_size = data->desc_size; + map.flags = data->flags; + + set_bit(EFI_MEMMAP, &efi.flags); + + efi.memmap = map; + + return 0; +} + +/** + * efi_memmap_init_early - Map the EFI memory map data structure + * @data: EFI memory map data + * + * Use early_memremap() to map the passed in EFI memory map and assign + * it to efi.memmap. + * + * Returns: zero on success, a negative error code on failure. + */ +int __init efi_memmap_init_early(struct efi_memory_map_data *data) +{ + /* Cannot go backwards */ + WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE); + + data->flags = 0; + return __efi_memmap_init(data); +} + +void __init efi_memmap_unmap(void) +{ + if (!efi_enabled(EFI_MEMMAP)) + return; + + if (!(efi.memmap.flags & EFI_MEMMAP_LATE)) { + unsigned long size; + + size = efi.memmap.desc_size * efi.memmap.nr_map; + early_memunmap(efi.memmap.map, size); + } else { + memunmap(efi.memmap.map); + } + + efi.memmap.map = NULL; + clear_bit(EFI_MEMMAP, &efi.flags); +} + +/** + * efi_memmap_init_late - Map efi.memmap with memremap() + * @addr: Physical address of the new EFI memory map + * @size: Size in bytes of the new EFI memory map + * + * Setup a mapping of the EFI memory map using ioremap_cache(). This + * function should only be called once the vmalloc space has been + * setup and is therefore not suitable for calling during early EFI + * initialise, e.g. in efi_init(). Additionally, it expects + * efi_memmap_init_early() to have already been called. + * + * The reason there are two EFI memmap initialisation + * (efi_memmap_init_early() and this late version) is because the + * early EFI memmap should be explicitly unmapped once EFI + * initialisation is complete as the fixmap space used to map the EFI + * memmap (via early_memremap()) is a scarce resource. + * + * This late mapping is intended to persist for the duration of + * runtime so that things like efi_mem_desc_lookup() and + * efi_mem_attributes() always work. + * + * Returns: zero on success, a negative error code on failure. + */ +int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size) +{ + struct efi_memory_map_data data = { + .phys_map = addr, + .size = size, + .flags = EFI_MEMMAP_LATE, + }; + + /* Did we forget to unmap the early EFI memmap? */ + WARN_ON(efi.memmap.map); + + /* Were we already called? */ + WARN_ON(efi.memmap.flags & EFI_MEMMAP_LATE); + + /* + * It makes no sense to allow callers to register different + * values for the following fields. Copy them out of the + * existing early EFI memmap. + */ + data.desc_version = efi.memmap.desc_version; + data.desc_size = efi.memmap.desc_size; + + return __efi_memmap_init(&data); +} -- cgit v1.3.1