diff options
Diffstat (limited to 'kernel/trace/trace_syscalls.c')
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 166 |
1 files changed, 143 insertions, 23 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 527e17eae57..51213b0aa81 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -14,6 +14,69 @@ static int sys_refcount_exit; static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls); static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls); +extern unsigned long __start_syscalls_metadata[]; +extern unsigned long __stop_syscalls_metadata[]; + +static struct syscall_metadata **syscalls_metadata; + +static struct syscall_metadata *find_syscall_meta(unsigned long syscall) +{ + struct syscall_metadata *start; + struct syscall_metadata *stop; + char str[KSYM_SYMBOL_LEN]; + + + start = (struct syscall_metadata *)__start_syscalls_metadata; + stop = (struct syscall_metadata *)__stop_syscalls_metadata; + kallsyms_lookup(syscall, NULL, NULL, NULL, str); + + for ( ; start < stop; start++) { + /* + * Only compare after the "sys" prefix. Archs that use + * syscall wrappers may have syscalls symbols aliases prefixed + * with "SyS" instead of "sys", leading to an unwanted + * mismatch. + */ + if (start->name && !strcmp(start->name + 3, str + 3)) + return start; + } + return NULL; +} + +static struct syscall_metadata *syscall_nr_to_meta(int nr) +{ + if (!syscalls_metadata || nr >= NR_syscalls || nr < 0) + return NULL; + + return syscalls_metadata[nr]; +} + +int syscall_name_to_nr(char *name) +{ + int i; + + if (!syscalls_metadata) + return -1; + + for (i = 0; i < NR_syscalls; i++) { + if (syscalls_metadata[i]) { + if (!strcmp(syscalls_metadata[i]->name, name)) + return i; + } + } + return -1; +} + +void set_syscall_enter_id(int num, int id) +{ + syscalls_metadata[num]->enter_id = id; +} + +void set_syscall_exit_id(int num, int id) +{ + syscalls_metadata[num]->exit_id = id; +} + enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags) { @@ -103,7 +166,8 @@ extern char *__bad_type_size(void); #define SYSCALL_FIELD(type, name) \ sizeof(type) != sizeof(trace.name) ? \ __bad_type_size() : \ - #type, #name, offsetof(typeof(trace), name), sizeof(trace.name) + #type, #name, offsetof(typeof(trace), name), \ + sizeof(trace.name), is_signed_type(type) int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s) { @@ -120,7 +184,8 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s) if (!entry) return 0; - ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n", + ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;" + "\tsigned:%u;\n", SYSCALL_FIELD(int, nr)); if (!ret) return 0; @@ -130,8 +195,10 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s) entry->args[i]); if (!ret) return 0; - ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;\n", offset, - sizeof(unsigned long)); + ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;" + "\tsigned:%u;\n", offset, + sizeof(unsigned long), + is_signed_type(unsigned long)); if (!ret) return 0; offset += sizeof(unsigned long); @@ -163,8 +230,10 @@ int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s) struct syscall_trace_exit trace; ret = trace_seq_printf(s, - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n" - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\n", + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;" + "\tsigned:%u;\n" + "\tfield:%s %s;\toffset:%zu;\tsize:%zu;" + "\tsigned:%u;\n", SYSCALL_FIELD(int, nr), SYSCALL_FIELD(long, ret)); if (!ret) @@ -212,7 +281,7 @@ int syscall_exit_define_fields(struct ftrace_event_call *call) if (ret) return ret; - ret = trace_define_field(call, SYSCALL_FIELD(long, ret), 0, + ret = trace_define_field(call, SYSCALL_FIELD(long, ret), FILTER_OTHER); return ret; @@ -285,13 +354,13 @@ void ftrace_syscall_exit(struct pt_regs *regs, long ret) trace_current_buffer_unlock_commit(buffer, event, 0, 0); } -int reg_event_syscall_enter(void *ptr) +int reg_event_syscall_enter(struct ftrace_event_call *call) { int ret = 0; int num; char *name; - name = (char *)ptr; + name = (char *)call->data; num = syscall_name_to_nr(name); if (num < 0 || num >= NR_syscalls) return -ENOSYS; @@ -309,12 +378,12 @@ int reg_event_syscall_enter(void *ptr) return ret; } -void unreg_event_syscall_enter(void *ptr) +void unreg_event_syscall_enter(struct ftrace_event_call *call) { int num; char *name; - name = (char *)ptr; + name = (char *)call->data; num = syscall_name_to_nr(name); if (num < 0 || num >= NR_syscalls) return; @@ -326,13 +395,13 @@ void unreg_event_syscall_enter(void *ptr) mutex_unlock(&syscall_trace_lock); } -int reg_event_syscall_exit(void *ptr) +int reg_event_syscall_exit(struct ftrace_event_call *call) { int ret = 0; int num; char *name; - name = (char *)ptr; + name = call->data; num = syscall_name_to_nr(name); if (num < 0 || num >= NR_syscalls) return -ENOSYS; @@ -350,12 +419,12 @@ int reg_event_syscall_exit(void *ptr) return ret; } -void unreg_event_syscall_exit(void *ptr) +void unreg_event_syscall_exit(struct ftrace_event_call *call) { int num; char *name; - name = (char *)ptr; + name = call->data; num = syscall_name_to_nr(name); if (num < 0 || num >= NR_syscalls) return; @@ -375,6 +444,29 @@ struct trace_event event_syscall_exit = { .trace = print_syscall_exit, }; +int __init init_ftrace_syscalls(void) +{ + struct syscall_metadata *meta; + unsigned long addr; + int i; + + syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * + NR_syscalls, GFP_KERNEL); + if (!syscalls_metadata) { + WARN_ON(1); + return -ENOMEM; + } + + for (i = 0; i < NR_syscalls; i++) { + addr = arch_syscall_addr(i); + meta = find_syscall_meta(addr); + syscalls_metadata[i] = meta; + } + + return 0; +} +core_initcall(init_ftrace_syscalls); + #ifdef CONFIG_EVENT_PROFILE static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls); @@ -385,6 +477,7 @@ static int sys_prof_refcount_exit; static void prof_syscall_enter(struct pt_regs *regs, long id) { struct syscall_metadata *sys_data; + struct perf_trace_buf *trace_buf; struct syscall_trace_enter *rec; unsigned long flags; char *raw_data; @@ -415,14 +508,25 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) cpu = smp_processor_id(); if (in_nmi()) - raw_data = rcu_dereference(trace_profile_buf_nmi); + trace_buf = rcu_dereference(perf_trace_buf_nmi); else - raw_data = rcu_dereference(trace_profile_buf); + trace_buf = rcu_dereference(perf_trace_buf); - if (!raw_data) + if (!trace_buf) goto end; - raw_data = per_cpu_ptr(raw_data, cpu); + trace_buf = per_cpu_ptr(trace_buf, cpu); + + if (trace_buf->recursion++) + goto end_recursion; + + /* + * Make recursion update visible before entering perf_tp_event + * so that we protect from perf recursions. + */ + barrier(); + + raw_data = trace_buf->buf; /* zero the dead bytes from align to not leak stack to user */ *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; @@ -435,6 +539,8 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) (unsigned long *)&rec->args); perf_tp_event(sys_data->enter_id, 0, 1, rec, size); +end_recursion: + trace_buf->recursion--; end: local_irq_restore(flags); } @@ -482,6 +588,7 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) { struct syscall_metadata *sys_data; struct syscall_trace_exit *rec; + struct perf_trace_buf *trace_buf; unsigned long flags; int syscall_nr; char *raw_data; @@ -513,14 +620,25 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) cpu = smp_processor_id(); if (in_nmi()) - raw_data = rcu_dereference(trace_profile_buf_nmi); + trace_buf = rcu_dereference(perf_trace_buf_nmi); else - raw_data = rcu_dereference(trace_profile_buf); + trace_buf = rcu_dereference(perf_trace_buf); - if (!raw_data) + if (!trace_buf) goto end; - raw_data = per_cpu_ptr(raw_data, cpu); + trace_buf = per_cpu_ptr(trace_buf, cpu); + + if (trace_buf->recursion++) + goto end_recursion; + + /* + * Make recursion update visible before entering perf_tp_event + * so that we protect from perf recursions. + */ + barrier(); + + raw_data = trace_buf->buf; /* zero the dead bytes from align to not leak stack to user */ *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; @@ -534,6 +652,8 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) perf_tp_event(sys_data->exit_id, 0, 1, rec, size); +end_recursion: + trace_buf->recursion--; end: local_irq_restore(flags); } |