diff options
Diffstat (limited to 'kernel/trace/trace_printk.c')
| -rw-r--r-- | kernel/trace/trace_printk.c | 85 |
1 files changed, 68 insertions, 17 deletions
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c index a9077c1b4ad3..29f6e95439b6 100644 --- a/kernel/trace/trace_printk.c +++ b/kernel/trace/trace_printk.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * trace binary printk * @@ -5,7 +6,7 @@ * */ #include <linux/seq_file.h> -#include <linux/debugfs.h> +#include <linux/security.h> #include <linux/uaccess.h> #include <linux/kernel.h> #include <linux/ftrace.h> @@ -15,7 +16,6 @@ #include <linux/ctype.h> #include <linux/list.h> #include <linux/slab.h> -#include <linux/fs.h> #include "trace.h" @@ -38,6 +38,10 @@ struct trace_bprintk_fmt { static inline struct trace_bprintk_fmt *lookup_format(const char *fmt) { struct trace_bprintk_fmt *pos; + + if (!fmt) + return ERR_PTR(-EINVAL); + list_for_each_entry(pos, &trace_bprintk_fmt_list, list) { if (!strcmp(pos->fmt, fmt)) return pos; @@ -59,7 +63,8 @@ void hold_module_trace_bprintk_format(const char **start, const char **end) for (iter = start; iter < end; iter++) { struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter); if (tb_fmt) { - *iter = tb_fmt->fmt; + if (!IS_ERR(tb_fmt)) + *iter = tb_fmt->fmt; continue; } @@ -91,7 +96,7 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self, if (val == MODULE_STATE_COMING) hold_module_trace_bprintk_format(start, end); } - return 0; + return NOTIFY_OK; } /* @@ -111,7 +116,7 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self, * section, then we need to read the link list pointers. The trick is * we pass the address of the string to the seq function just like * we do for the kernel core formats. To get back the structure that - * holds the format, we simply use containerof() and then go to the + * holds the format, we simply use container_of() and then go to the * next format in the list. */ static const char ** @@ -169,7 +174,7 @@ __init static int module_trace_bprintk_format_notify(struct notifier_block *self, unsigned long val, void *data) { - return 0; + return NOTIFY_OK; } static inline const char ** find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) @@ -180,6 +185,12 @@ static inline void format_mod_start(void) { } static inline void format_mod_stop(void) { } #endif /* CONFIG_MODULES */ +static bool __read_mostly trace_printk_enabled = true; + +void trace_printk_control(bool enabled) +{ + trace_printk_enabled = enabled; +} __initdata_or_module static struct notifier_block module_trace_bprintk_format_nb = { @@ -187,14 +198,14 @@ struct notifier_block module_trace_bprintk_format_nb = { }; int __trace_bprintk(unsigned long ip, const char *fmt, ...) - { +{ int ret; va_list ap; if (unlikely(!fmt)) return 0; - if (!(trace_flags & TRACE_ITER_PRINTK)) + if (!trace_printk_enabled) return 0; va_start(ap, fmt); @@ -205,11 +216,11 @@ int __trace_bprintk(unsigned long ip, const char *fmt, ...) EXPORT_SYMBOL_GPL(__trace_bprintk); int __ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap) - { +{ if (unlikely(!fmt)) return 0; - if (!(trace_flags & TRACE_ITER_PRINTK)) + if (!trace_printk_enabled) return 0; return trace_vbprintk(ip, fmt, ap); @@ -221,7 +232,7 @@ int __trace_printk(unsigned long ip, const char *fmt, ...) int ret; va_list ap; - if (!(trace_flags & TRACE_ITER_PRINTK)) + if (!trace_printk_enabled) return 0; va_start(ap, fmt); @@ -233,23 +244,54 @@ EXPORT_SYMBOL_GPL(__trace_printk); int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap) { - if (!(trace_flags & TRACE_ITER_PRINTK)) + if (!trace_printk_enabled) return 0; return trace_vprintk(ip, fmt, ap); } EXPORT_SYMBOL_GPL(__ftrace_vprintk); +bool trace_is_tracepoint_string(const char *str) +{ + const char **ptr = __start___tracepoint_str; + + for (ptr = __start___tracepoint_str; ptr < __stop___tracepoint_str; ptr++) { + if (str == *ptr) + return true; + } + return false; +} + static const char **find_next(void *v, loff_t *pos) { const char **fmt = v; int start_index; + int last_index; start_index = __stop___trace_bprintk_fmt - __start___trace_bprintk_fmt; if (*pos < start_index) return __start___trace_bprintk_fmt + *pos; + /* + * The __tracepoint_str section is treated the same as the + * __trace_printk_fmt section. The difference is that the + * __trace_printk_fmt section should only be used by trace_printk() + * in a debugging environment, as if anything exists in that section + * the trace_prink() helper buffers are allocated, which would just + * waste space in a production environment. + * + * The __tracepoint_str sections on the other hand are used by + * tracepoints which need to map pointers to their strings to + * the ASCII text for userspace. + */ + last_index = start_index; + start_index = __stop___tracepoint_str - __start___tracepoint_str; + + if (*pos < last_index + start_index) + return __start___tracepoint_str + (*pos - last_index); + + start_index += last_index; return find_next_mod_format(start_index, v, fmt, pos); } @@ -272,6 +314,9 @@ static int t_show(struct seq_file *m, void *v) const char *str = *fmt; int i; + if (!*fmt) + return 0; + seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt); /* @@ -286,7 +331,7 @@ static int t_show(struct seq_file *m, void *v) seq_puts(m, "\\t"); break; case '\\': - seq_puts(m, "\\"); + seq_putc(m, '\\'); break; case '"': seq_puts(m, "\\\""); @@ -315,6 +360,12 @@ static const struct seq_operations show_format_seq_ops = { static int ftrace_formats_open(struct inode *inode, struct file *file) { + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + return seq_open(file, &show_format_seq_ops); } @@ -327,13 +378,13 @@ static const struct file_operations ftrace_formats_fops = { static __init int init_trace_printk_function_export(void) { - struct dentry *d_tracer; + int ret; - d_tracer = tracing_init_dentry(); - if (!d_tracer) + ret = tracing_init_dentry(); + if (ret) return 0; - trace_create_file("printk_formats", 0444, d_tracer, + trace_create_file("printk_formats", TRACE_MODE_READ, NULL, NULL, &ftrace_formats_fops); return 0; |