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Commit 10f49021 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-v5.0-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace 

Pull tracing fixes from Steven Rostedt:
 "Two more tracing fixes

   - Have kprobes not use copy_from_user() to access kernel addresses,
     because kprobes can legitimately poke at bad kernel memory, which
     will fault. Copy from user code should never fault in kernel space.
     Using probe_mem_read() can handle kernel address space faulting.

   - Put back the entries counter in the tracing output that was
     accidentally removed"

* tag 'trace-v5.0-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix number of entries in trace header
  kprobe: Do not use uaccess functions to access kernel memory that can fault
parents a3b22b9f 9e738215

kernel/trace/trace.c

+2 −0
Original line number Diff line number Diff line
@@ -3384,6 +3384,8 @@ static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file 
	const char tgid_space[] = "          ";

	const char space[] = "  ";



	print_event_info(buf, m);



	seq_printf(m, "#                          %s  _-----=> irqs-off\n",

		   tgid ? tgid_space : space);

	seq_printf(m, "#                          %s / _----=> need-resched\n",

kernel/trace/trace_kprobe.c

+1 −9
Original line number Diff line number Diff line
@@ -861,22 +861,14 @@ static const struct file_operations kprobe_profile_ops = { 
static nokprobe_inline int

fetch_store_strlen(unsigned long addr)

{

	mm_segment_t old_fs;

	int ret, len = 0;

	u8 c;



	old_fs = get_fs();

	set_fs(KERNEL_DS);

	pagefault_disable();



	do {

		ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);

		ret = probe_mem_read(&c, (u8 *)addr + len, 1);

		len++;

	} while (c && ret == 0 && len < MAX_STRING_SIZE);



	pagefault_enable();

	set_fs(old_fs);



	return (ret < 0) ? ret : len;

}