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 --- tools/perf/util/mmap.c | 369 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 369 insertions(+) create mode 100644 tools/perf/util/mmap.c (limited to 'tools/perf/util/mmap.c') diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c new file mode 100644 index 000000000..358e70c4f --- /dev/null +++ b/tools/perf/util/mmap.c @@ -0,0 +1,369 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2011-2017, Red Hat Inc, Arnaldo Carvalho de Melo + * + * Parts came from evlist.c builtin-{top,stat,record}.c, see those files for further + * copyright notes. + */ + +#include +#include +#include +#include +#include +#include +#include +#include // sysconf() +#include +#ifdef HAVE_LIBNUMA_SUPPORT +#include +#endif +#include "cpumap.h" +#include "debug.h" +#include "event.h" +#include "mmap.h" +#include "../perf.h" +#include /* page_size */ +#include + +#define MASK_SIZE 1023 +void mmap_cpu_mask__scnprintf(struct mmap_cpu_mask *mask, const char *tag) +{ + char buf[MASK_SIZE + 1]; + size_t len; + + len = bitmap_scnprintf(mask->bits, mask->nbits, buf, MASK_SIZE); + buf[len] = '\0'; + pr_debug("%p: %s mask[%zd]: %s\n", mask, tag, mask->nbits, buf); +} + +size_t mmap__mmap_len(struct mmap *map) +{ + return perf_mmap__mmap_len(&map->core); +} + +int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused, + struct auxtrace_mmap_params *mp __maybe_unused, + void *userpg __maybe_unused, + int fd __maybe_unused) +{ + return 0; +} + +void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused) +{ +} + +void __weak auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp __maybe_unused, + off_t auxtrace_offset __maybe_unused, + unsigned int auxtrace_pages __maybe_unused, + bool auxtrace_overwrite __maybe_unused) +{ +} + +void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __maybe_unused, + struct evlist *evlist __maybe_unused, + struct evsel *evsel __maybe_unused, + int idx __maybe_unused) +{ +} + +#ifdef HAVE_AIO_SUPPORT +static int perf_mmap__aio_enabled(struct mmap *map) +{ + return map->aio.nr_cblocks > 0; +} + +#ifdef HAVE_LIBNUMA_SUPPORT +static int perf_mmap__aio_alloc(struct mmap *map, int idx) +{ + map->aio.data[idx] = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE, + MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); + if (map->aio.data[idx] == MAP_FAILED) { + map->aio.data[idx] = NULL; + return -1; + } + + return 0; +} + +static void perf_mmap__aio_free(struct mmap *map, int idx) +{ + if (!map->aio.data || !map->aio.data[idx]) + return; + munmap(map->aio.data[idx], mmap__mmap_len(map)); + map->aio.data[idx] = NULL; +} + +static int perf_mmap__aio_bind(struct mmap *map, int idx, struct perf_cpu cpu, int affinity) +{ + void *data; + size_t mmap_len; + unsigned long *node_mask; + unsigned long node_index; + int err = 0; + + if (affinity != PERF_AFFINITY_SYS && cpu__max_node() > 1) { + int node; + + data = map->aio.data[idx]; + mmap_len = mmap__mmap_len(map); + node = cpu__get_node(cpu); + /* -1 sign-extends to ULONG_MAX, wrapping bitmap_zalloc(0) and OOB __set_bit */ + if (node < 0) + return 0; + node_index = node; + node_mask = bitmap_zalloc(node_index + 1); + if (!node_mask) { + pr_err("Failed to allocate node mask for mbind: error %m\n"); + return -1; + } + __set_bit(node_index, node_mask); + if (mbind(data, mmap_len, MPOL_BIND, node_mask, node_index + 1 + 1, 0)) { + pr_err("Failed to bind [%p-%p] AIO buffer to node %lu: error %m\n", + data, data + mmap_len, node_index); + err = -1; + } + bitmap_free(node_mask); + } + + return err; +} +#else /* !HAVE_LIBNUMA_SUPPORT */ +static int perf_mmap__aio_alloc(struct mmap *map, int idx) +{ + map->aio.data[idx] = malloc(mmap__mmap_len(map)); + if (map->aio.data[idx] == NULL) + return -1; + + return 0; +} + +static void perf_mmap__aio_free(struct mmap *map, int idx) +{ + if (!map->aio.data) + return; + zfree(&(map->aio.data[idx])); +} + +static int perf_mmap__aio_bind(struct mmap *map __maybe_unused, int idx __maybe_unused, + struct perf_cpu cpu __maybe_unused, int affinity __maybe_unused) +{ + return 0; +} +#endif + +static int perf_mmap__aio_mmap(struct mmap *map, struct mmap_params *mp) +{ + int delta_max, i, prio, ret; + + map->aio.nr_cblocks = mp->nr_cblocks; + if (map->aio.nr_cblocks) { + map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *)); + if (!map->aio.aiocb) { + pr_debug2("failed to allocate aiocb for data buffer, error %m\n"); + return -1; + } + map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb)); + if (!map->aio.cblocks) { + pr_debug2("failed to allocate cblocks for data buffer, error %m\n"); + return -1; + } + map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *)); + if (!map->aio.data) { + pr_debug2("failed to allocate data buffer, error %m\n"); + return -1; + } + delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX); + for (i = 0; i < map->aio.nr_cblocks; ++i) { + ret = perf_mmap__aio_alloc(map, i); + if (ret == -1) { + pr_debug2("failed to allocate data buffer area, error %m"); + return -1; + } + ret = perf_mmap__aio_bind(map, i, map->core.cpu, mp->affinity); + if (ret == -1) + return -1; + /* + * Use cblock.aio_fildes value different from -1 + * to denote started aio write operation on the + * cblock so it requires explicit record__aio_sync() + * call prior the cblock may be reused again. + */ + map->aio.cblocks[i].aio_fildes = -1; + /* + * Allocate cblocks with priority delta to have + * faster aio write system calls because queued requests + * are kept in separate per-prio queues and adding + * a new request will iterate thru shorter per-prio + * list. Blocks with numbers higher than + * _SC_AIO_PRIO_DELTA_MAX go with priority 0. + */ + prio = delta_max - i; + map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0; + } + } + + return 0; +} + +static void perf_mmap__aio_munmap(struct mmap *map) +{ + int i; + + for (i = 0; i < map->aio.nr_cblocks; ++i) + perf_mmap__aio_free(map, i); + if (map->aio.data) + zfree(&map->aio.data); + zfree(&map->aio.cblocks); + zfree(&map->aio.aiocb); +} +#else /* !HAVE_AIO_SUPPORT */ +static int perf_mmap__aio_enabled(struct mmap *map __maybe_unused) +{ + return 0; +} + +static int perf_mmap__aio_mmap(struct mmap *map __maybe_unused, + struct mmap_params *mp __maybe_unused) +{ + return 0; +} + +static void perf_mmap__aio_munmap(struct mmap *map __maybe_unused) +{ +} +#endif + +void mmap__munmap(struct mmap *map) +{ + bitmap_free(map->affinity_mask.bits); + map->affinity_mask.bits = NULL; + map->affinity_mask.nbits = 0; + + zstd_fini(&map->zstd_data); + + perf_mmap__aio_munmap(map); + if (map->data != NULL) { + munmap(map->data, mmap__mmap_len(map)); + map->data = NULL; + } + auxtrace_mmap__munmap(&map->auxtrace_mmap); +} + +static void build_node_mask(int node, struct mmap_cpu_mask *mask) +{ + int idx, nr_cpus; + struct perf_cpu cpu; + struct perf_cpu_map *cpu_map = cpu_map__online(); + + if (!cpu_map) + return; + + nr_cpus = perf_cpu_map__nr(cpu_map); + for (idx = 0; idx < nr_cpus; idx++) { + cpu = perf_cpu_map__cpu(cpu_map, idx); /* map c index to online cpu index */ + if (cpu__get_node(cpu) == node) + __set_bit(cpu.cpu, mask->bits); + } + perf_cpu_map__put(cpu_map); +} + +static int perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp) +{ + map->affinity_mask.nbits = cpu__max_cpu().cpu; + map->affinity_mask.bits = bitmap_zalloc(map->affinity_mask.nbits); + if (!map->affinity_mask.bits) + return -1; + + if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1) + build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask); + else if (mp->affinity == PERF_AFFINITY_CPU) + __set_bit(map->core.cpu.cpu, map->affinity_mask.bits); + + return 0; +} + +int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, struct perf_cpu cpu) +{ + if (perf_mmap__mmap(&map->core, &mp->core, fd, cpu)) { + pr_debug2("failed to mmap perf event ring buffer, error %d\n", + errno); + return -1; + } + + if (mp->affinity != PERF_AFFINITY_SYS && + perf_mmap__setup_affinity_mask(map, mp)) { + pr_debug2("failed to alloc mmap affinity mask, error %d\n", + errno); + return -1; + } + + if (verbose == 2) + mmap_cpu_mask__scnprintf(&map->affinity_mask, "mmap"); + + map->core.flush = mp->flush; + + if (zstd_init(&map->zstd_data, mp->comp_level)) { + pr_debug2("failed to init mmap compressor, error %d\n", errno); + return -1; + } + + if (mp->comp_level && !perf_mmap__aio_enabled(map)) { + map->data = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE, + MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); + if (map->data == MAP_FAILED) { + pr_debug2("failed to mmap data buffer, error %d\n", + errno); + map->data = NULL; + return -1; + } + } + + if (auxtrace_mmap__mmap(&map->auxtrace_mmap, + &mp->auxtrace_mp, map->core.base, fd)) + return -1; + + return perf_mmap__aio_mmap(map, mp); +} + +int perf_mmap__push(struct mmap *md, void *to, + int push(struct mmap *map, void *to, void *buf, size_t size)) +{ + u64 head = perf_mmap__read_head(&md->core); + unsigned char *data = md->core.base + page_size; + unsigned long size; + void *buf; + int rc = 0; + + rc = perf_mmap__read_init(&md->core); + if (rc < 0) + return (rc == -EAGAIN) ? 1 : -1; + + size = md->core.end - md->core.start; + + if ((md->core.start & md->core.mask) + size != (md->core.end & md->core.mask)) { + buf = &data[md->core.start & md->core.mask]; + size = md->core.mask + 1 - (md->core.start & md->core.mask); + md->core.start += size; + + if (push(md, to, buf, size) < 0) { + rc = -1; + goto out; + } + } + + buf = &data[md->core.start & md->core.mask]; + size = md->core.end - md->core.start; + md->core.start += size; + + if (push(md, to, buf, size) < 0) { + rc = -1; + goto out; + } + + md->core.prev = head; + perf_mmap__consume(&md->core); +out: + return rc; +} -- cgit v1.3.1