From: Ian Munsie FTRACE_SYSCALLS would create events for each and every system call, even if it had failed to map the system call's name with it's number. This resulted in a number of events being created that would not behave as expected. This could happen, for example, on architectures who's symbol names are unusual and will not match the system call name. It could also happen with system calls which were mapped to sys_ni_syscall. This patch changes the default system call number in the metadata to -1. If the system call name from the metadata is not successfully mapped to a system call number during boot, than the event initialisation routine will now return an error, preventing the event from being created. Signed-off-by: Ian Munsie LKML-Reference: <1296703645-18718-2-git-send-email-imunsie@au1.ibm.com> Signed-off-by: Steven Rostedt --- include/linux/syscalls.h | 2 ++ kernel/trace/trace_syscalls.c | 8 ++++++++ 2 files changed, 10 insertions(+), 0 deletions(-) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 98664db..8e8968e 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -158,6 +158,7 @@ extern struct trace_event_functions exit_syscall_print_funcs; static struct syscall_metadata __used \ __syscall_meta_##sname = { \ .name = "sys"#sname, \ + .syscall_nr = -1, /* Filled in at boot */ \ .nb_args = nb, \ .types = types_##sname, \ .args = args_##sname, \ @@ -175,6 +176,7 @@ extern struct trace_event_functions exit_syscall_print_funcs; static struct syscall_metadata __used \ __syscall_meta__##sname = { \ .name = "sys_"#sname, \ + .syscall_nr = -1, /* Filled in at boot */ \ .nb_args = 0, \ .enter_event = &event_enter__##sname, \ .exit_event = &event_exit__##sname, \ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 5c9fe08..a9ceabd 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -424,6 +424,14 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call) int init_syscall_trace(struct ftrace_event_call *call) { int id; + int num; + + num = ((struct syscall_metadata *)call->data)->syscall_nr; + if (num < 0 || num >= NR_syscalls) { + pr_debug("syscall %s metadata not mapped, disabling ftrace event\n", + ((struct syscall_metadata *)call->data)->name); + return -ENOSYS; + } if (set_syscall_print_fmt(call) < 0) return -ENOMEM; -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/