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 --- tools/perf/util/debug.c | 380 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 380 insertions(+) create mode 100644 tools/perf/util/debug.c (limited to 'tools/perf/util/debug.c') diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c new file mode 100644 index 000000000..6b5ffe81f --- /dev/null +++ b/tools/perf/util/debug.c @@ -0,0 +1,380 @@ +// SPDX-License-Identifier: GPL-2.0 +/* For general debugging purposes */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#ifdef HAVE_BACKTRACE_SUPPORT +#include +#endif +#include "addr_location.h" +#include "color.h" +#include "debug.h" +#include "env.h" +#include "event.h" +#include "machine.h" +#include "map.h" +#include "print_binary.h" +#include "srcline.h" +#include "symbol.h" +#include "synthetic-events.h" +#include "target.h" +#include "thread.h" +#include "trace-event.h" +#include "ui/helpline.h" +#include "ui/ui.h" +#include "util/parse-sublevel-options.h" + +#include + +#ifdef HAVE_LIBTRACEEVENT +#include +#else +#define LIBTRACEEVENT_VERSION 0 +#endif + +int verbose; +int debug_kmaps; +int debug_peo_args; +bool dump_trace = false, quiet = false; +int debug_ordered_events; +static int redirect_to_stderr; +int debug_data_convert; +static FILE *_debug_file; +static bool debug_display_time; +int debug_type_profile; + +FILE *debug_file(void) +{ + if (!_debug_file) { + debug_set_file(stderr); + pr_warning_once("debug_file not set"); + } + return _debug_file; +} + +void debug_set_file(FILE *file) +{ + _debug_file = file; +} + +void debug_set_display_time(bool set) +{ + debug_display_time = set; +} + +static int fprintf_time(FILE *file) +{ + struct timeval tod; + struct tm ltime; + char date[64]; + + if (!debug_display_time) + return 0; + + if (gettimeofday(&tod, NULL) != 0) + return 0; + + if (localtime_r(&tod.tv_sec, <ime) == NULL) + return 0; + + strftime(date, sizeof(date), "%F %H:%M:%S", <ime); + return fprintf(file, "[%s.%06lu] ", date, (long)tod.tv_usec); +} + +int veprintf(int level, int var, const char *fmt, va_list args) +{ + int ret = 0; + + if (var >= level) { + if (use_browser >= 1 && !redirect_to_stderr) { + ui_helpline__vshow(fmt, args); + } else { + ret = fprintf_time(debug_file()); + ret += vfprintf(debug_file(), fmt, args); + } + } + + return ret; +} + +int eprintf(int level, int var, const char *fmt, ...) +{ + va_list args; + int ret; + + va_start(args, fmt); + ret = veprintf(level, var, fmt, args); + va_end(args); + + return ret; +} + +static int veprintf_time(u64 t, const char *fmt, va_list args) +{ + int ret = 0; + u64 secs, usecs, nsecs = t; + + secs = nsecs / NSEC_PER_SEC; + nsecs -= secs * NSEC_PER_SEC; + usecs = nsecs / NSEC_PER_USEC; + + ret = fprintf(debug_file(), "[%13" PRIu64 ".%06" PRIu64 "] ", secs, usecs); + ret += vfprintf(debug_file(), fmt, args); + return ret; +} + +int eprintf_time(int level, int var, u64 t, const char *fmt, ...) +{ + int ret = 0; + va_list args; + + if (var >= level) { + va_start(args, fmt); + ret = veprintf_time(t, fmt, args); + va_end(args); + } + + return ret; +} + +/* + * Overloading libtraceevent standard info print + * function, display with -v in perf. + */ +void pr_stat(const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + veprintf(1, verbose, fmt, args); + va_end(args); + eprintf(1, verbose, "\n"); +} + +int dump_printf(const char *fmt, ...) +{ + va_list args; + int ret = 0; + + if (dump_trace) { + va_start(args, fmt); + ret = vprintf(fmt, args); + va_end(args); + } + + return ret; +} + +static int trace_event_printer(enum binary_printer_ops op, + unsigned int val, void *extra, FILE *fp) +{ + const char *color = PERF_COLOR_BLUE; + union perf_event *event = (union perf_event *)extra; + unsigned char ch = (unsigned char)val; + int printed = 0; + + switch (op) { + case BINARY_PRINT_DATA_BEGIN: + printed += fprintf(fp, "."); + printed += color_fprintf(fp, color, "\n. ... raw event: size %d bytes\n", + event->header.size); + break; + case BINARY_PRINT_LINE_BEGIN: + printed += fprintf(fp, "."); + break; + case BINARY_PRINT_ADDR: + printed += color_fprintf(fp, color, " %04x: ", val); + break; + case BINARY_PRINT_NUM_DATA: + printed += color_fprintf(fp, color, " %02x", val); + break; + case BINARY_PRINT_NUM_PAD: + printed += color_fprintf(fp, color, " "); + break; + case BINARY_PRINT_SEP: + printed += color_fprintf(fp, color, " "); + break; + case BINARY_PRINT_CHAR_DATA: + printed += color_fprintf(fp, color, "%c", + isprint(ch) && isascii(ch) ? ch : '.'); + break; + case BINARY_PRINT_CHAR_PAD: + printed += color_fprintf(fp, color, " "); + break; + case BINARY_PRINT_LINE_END: + printed += color_fprintf(fp, color, "\n"); + break; + case BINARY_PRINT_DATA_END: + printed += fprintf(fp, "\n"); + break; + default: + break; + } + + return printed; +} + +void trace_event(union perf_event *event) +{ + unsigned char *raw_event = (void *)event; + + if (!dump_trace) + return; + + print_binary(raw_event, event->header.size, 16, + trace_event_printer, event); +} + +static struct sublevel_option debug_opts[] = { + { .name = "verbose", .value_ptr = &verbose }, + { .name = "ordered-events", .value_ptr = &debug_ordered_events}, + { .name = "stderr", .value_ptr = &redirect_to_stderr}, + { .name = "data-convert", .value_ptr = &debug_data_convert }, + { .name = "perf-event-open", .value_ptr = &debug_peo_args }, + { .name = "kmaps", .value_ptr = &debug_kmaps }, + { .name = "type-profile", .value_ptr = &debug_type_profile }, + { .name = NULL, } +}; + +int perf_debug_option(const char *str) +{ + int ret; + + ret = perf_parse_sublevel_options(str, debug_opts); + if (ret) + return ret; + + /* Allow only verbose value in range (0, 10), otherwise set 0. */ + verbose = (verbose < 0) || (verbose > 10) ? 0 : verbose; + +#if LIBTRACEEVENT_VERSION >= MAKE_LIBTRACEEVENT_VERSION(1, 3, 0) + if (verbose == 1) + tep_set_loglevel(TEP_LOG_INFO); + else if (verbose == 2) + tep_set_loglevel(TEP_LOG_DEBUG); + else if (verbose >= 3) + tep_set_loglevel(TEP_LOG_ALL); +#endif + return 0; +} + +int perf_quiet_option(void) +{ + struct sublevel_option *opt = &debug_opts[0]; + + /* disable all debug messages */ + while (opt->name) { + *opt->value_ptr = -1; + opt++; + } + + /* For debug variables that are used as bool types, set to 0. */ + redirect_to_stderr = 0; + debug_peo_args = 0; + debug_kmaps = 0; + debug_type_profile = 0; + + return 0; +} + +#define DEBUG_WRAPPER(__n, __l) \ +static int pr_ ## __n ## _wrapper(const char *fmt, ...) \ +{ \ + va_list args; \ + int ret; \ + \ + va_start(args, fmt); \ + ret = veprintf(__l, verbose, fmt, args); \ + va_end(args); \ + return ret; \ +} + +DEBUG_WRAPPER(warning, 0); +DEBUG_WRAPPER(debug, 1); + +void perf_debug_setup(void) +{ + debug_set_file(stderr); + libapi_set_print(pr_warning_wrapper, pr_warning_wrapper, pr_debug_wrapper); +} + +void __dump_stack(FILE *file, void **stackdump, size_t stackdump_size) +{ + /* TODO: async safety. printf, malloc, etc. aren't safe inside a signal handler. */ + pid_t pid = getpid(); + struct machine *machine; + struct thread *thread = NULL; + struct perf_env host_env; + + perf_env__init(&host_env); + machine = machine__new_live(&host_env, /*kernel_maps=*/false, pid); + + if (machine) + thread = machine__find_thread(machine, pid, pid); + +#ifdef HAVE_BACKTRACE_SUPPORT + if (!machine || !thread) { + /* + * Backtrace functions are async signal safe. Fall back on them + * if machine/thread creation fails. + */ + backtrace_symbols_fd(stackdump, stackdump_size, fileno(file)); + machine__delete(machine); + perf_env__exit(&host_env); + return; + } +#endif + + for (size_t i = 0; i < stackdump_size; i++) { + struct addr_location al; + u64 addr = (u64)(uintptr_t)stackdump[i]; + bool printed = false; + + addr_location__init(&al); + if (thread && thread__find_map(thread, PERF_RECORD_MISC_USER, addr, &al)) { + al.sym = map__find_symbol(al.map, al.addr); + if (al.sym) { + fprintf(file, " #%zd %p in %s ", i, stackdump[i], al.sym->name); + printed = true; + } + } + if (!printed) + fprintf(file, " #%zd %p ", i, stackdump[i]); + + map__fprintf_srcline(al.map, al.addr, "", file); + fprintf(file, "\n"); + addr_location__exit(&al); + } + thread__put(thread); + machine__delete(machine); + perf_env__exit(&host_env); +} + +/* Obtain a backtrace and print it to stdout. */ +#ifdef HAVE_BACKTRACE_SUPPORT +void dump_stack(void) +{ + void *stackdump[32]; + size_t size = backtrace(stackdump, ARRAY_SIZE(stackdump)); + + __dump_stack(stdout, stackdump, size); +} +#else +void dump_stack(void) {} +#endif + +void sighandler_dump_stack(int sig) +{ + psignal(sig, "perf"); + dump_stack(); + signal(sig, SIG_DFL); + raise(sig); +} -- cgit v1.3.1