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 --- lib/kunit/debugfs.c | 242 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 242 insertions(+) create mode 100644 lib/kunit/debugfs.c (limited to 'lib/kunit/debugfs.c') diff --git a/lib/kunit/debugfs.c b/lib/kunit/debugfs.c new file mode 100644 index 000000000..442b2ceb9 --- /dev/null +++ b/lib/kunit/debugfs.c @@ -0,0 +1,242 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2020, Oracle and/or its affiliates. + * Author: Alan Maguire + */ + +#include +#include + +#include +#include + +#include "string-stream.h" +#include "debugfs.h" + +#define KUNIT_DEBUGFS_ROOT "kunit" +#define KUNIT_DEBUGFS_RESULTS "results" +#define KUNIT_DEBUGFS_RUN "run" + +/* + * Create a debugfs representation of test suites: + * + * Path Semantics + * /sys/kernel/debug/kunit//results Show results of last run for + * testsuite + * /sys/kernel/debug/kunit//run Write to this file to trigger + * testsuite to run + * + */ + +static struct dentry *debugfs_rootdir; + +void kunit_debugfs_cleanup(void) +{ + debugfs_remove_recursive(debugfs_rootdir); +} + +void kunit_debugfs_init(void) +{ + if (!debugfs_rootdir) + debugfs_rootdir = debugfs_create_dir(KUNIT_DEBUGFS_ROOT, NULL); +} + +static void debugfs_print_result(struct seq_file *seq, struct string_stream *log) +{ + struct string_stream_fragment *frag_container; + + if (!log) + return; + + /* + * Walk the fragments so we don't need to allocate a temporary + * buffer to hold the entire string. + */ + spin_lock(&log->lock); + list_for_each_entry(frag_container, &log->fragments, node) + seq_printf(seq, "%s", frag_container->fragment); + spin_unlock(&log->lock); +} + +/* + * /sys/kernel/debug/kunit//results shows all results for testsuite. + */ +static int debugfs_print_results(struct seq_file *seq, void *v) +{ + struct kunit_suite *suite = (struct kunit_suite *)seq->private; + enum kunit_status success; + struct kunit_case *test_case; + + if (!suite) + return 0; + + success = kunit_suite_has_succeeded(suite); + + /* Print KTAP header so the debugfs log can be parsed as valid KTAP. */ + seq_puts(seq, "KTAP version 1\n"); + seq_puts(seq, "1..1\n"); + + if (suite->status != KUNIT_SKIPPED) { + /* Print suite header because it is not stored in the test logs. */ + seq_puts(seq, + KUNIT_SUBTEST_INDENT "KTAP version 1\n"); + seq_printf(seq, + KUNIT_SUBTEST_INDENT "# Subtest: %s\n", + suite->name); + seq_printf(seq, + KUNIT_SUBTEST_INDENT "1..%zd\n", + kunit_suite_num_test_cases(suite)); + + kunit_suite_for_each_test_case(suite, test_case) + debugfs_print_result(seq, test_case->log); + } + + debugfs_print_result(seq, suite->log); + + if (suite->status != KUNIT_SKIPPED) + seq_printf(seq, "%s %d %s\n", + kunit_status_to_ok_not_ok(success), 1, suite->name); + else + seq_printf(seq, "%s %d %s # SKIP %s\n", + kunit_status_to_ok_not_ok(success), 1, suite->name, + suite->status_comment); + return 0; +} + +static int debugfs_release(struct inode *inode, struct file *file) +{ + return single_release(inode, file); +} + +static int debugfs_results_open(struct inode *inode, struct file *file) +{ + struct kunit_suite *suite; + + suite = (struct kunit_suite *)inode->i_private; + + return single_open(file, debugfs_print_results, suite); +} + +/* + * Print a usage message to the debugfs "run" file + * (/sys/kernel/debug/kunit//run) if opened. + */ +static int debugfs_print_run(struct seq_file *seq, void *v) +{ + struct kunit_suite *suite = (struct kunit_suite *)seq->private; + + seq_puts(seq, "Write to this file to trigger the test suite to run.\n"); + seq_printf(seq, "usage: echo \"any string\" > /sys/kernel/debugfs/kunit/%s/run\n", + suite->name); + return 0; +} + +/* + * The debugfs "run" file (/sys/kernel/debug/kunit//run) + * contains no information. Write to the file to trigger the test suite + * to run. + */ +static int debugfs_run_open(struct inode *inode, struct file *file) +{ + struct kunit_suite *suite; + + suite = (struct kunit_suite *)inode->i_private; + + return single_open(file, debugfs_print_run, suite); +} + +/* + * Trigger a test suite to run by writing to the suite's "run" debugfs + * file found at: /sys/kernel/debug/kunit//run + * + * Note: what is written to this file will not be saved. + */ +static ssize_t debugfs_run(struct file *file, + const char __user *buf, size_t count, loff_t *ppos) +{ + struct inode *f_inode = file->f_inode; + struct kunit_suite *suite = (struct kunit_suite *) f_inode->i_private; + + __kunit_test_suites_init(&suite, 1, true); + + return count; +} + +static const struct file_operations debugfs_results_fops = { + .open = debugfs_results_open, + .read = seq_read, + .llseek = seq_lseek, + .release = debugfs_release, +}; + +static const struct file_operations debugfs_run_fops = { + .open = debugfs_run_open, + .read = seq_read, + .write = debugfs_run, + .llseek = seq_lseek, + .release = debugfs_release, +}; + +void kunit_debugfs_create_suite(struct kunit_suite *suite) +{ + struct kunit_case *test_case; + struct string_stream *stream; + + /* If suite log already allocated, do not create new debugfs files. */ + if (suite->log) + return; + + /* + * Allocate logs before creating debugfs representation. + * The suite->log and test_case->log pointer are expected to be NULL + * if there isn't a log, so only set it if the log stream was created + * successfully. + */ + stream = alloc_string_stream(GFP_KERNEL); + if (IS_ERR(stream)) + return; + + string_stream_set_append_newlines(stream, true); + suite->log = stream; + + kunit_suite_for_each_test_case(suite, test_case) { + stream = alloc_string_stream(GFP_KERNEL); + if (IS_ERR(stream)) + goto err; + + string_stream_set_append_newlines(stream, true); + test_case->log = stream; + } + + suite->debugfs = debugfs_create_dir(suite->name, debugfs_rootdir); + + debugfs_create_file(KUNIT_DEBUGFS_RESULTS, S_IFREG | 0444, + suite->debugfs, + suite, &debugfs_results_fops); + + /* Do not create file to re-run test if test runs on init */ + if (!suite->is_init) { + debugfs_create_file(KUNIT_DEBUGFS_RUN, S_IFREG | 0644, + suite->debugfs, + suite, &debugfs_run_fops); + } + return; + +err: + string_stream_destroy(suite->log); + suite->log = NULL; + kunit_suite_for_each_test_case(suite, test_case) { + string_stream_destroy(test_case->log); + test_case->log = NULL; + } +} + +void kunit_debugfs_destroy_suite(struct kunit_suite *suite) +{ + struct kunit_case *test_case; + + debugfs_remove_recursive(suite->debugfs); + string_stream_destroy(suite->log); + kunit_suite_for_each_test_case(suite, test_case) + string_stream_destroy(test_case->log); +} -- cgit v1.3.1