Commit 588b5938 authored Oct 10, 2018 by Greg Kroah-Hartman

linux-trace

Steven writes:
  "vsprint fix:

   It was reported that trace_printk() was not reporting properly
   values that came after a dereference pointer.

   trace_printk() utilizes vbin_printf() and bstr_printf() to keep the
   overhead of tracing down. vbin_printf() does not do any conversions
   and just stors the string format and the raw arguments into the
   buffer. bstr_printf() is used to read the buffer and does the
   conversions to complete the printf() output.

   This can be troublesome with dereferenced pointers because the
   reference may be different from the time vbin_printf() is called to
   the time bstr_printf() is called. To fix this, a prior commit changed
   vbin_printf() to convert dereferenced pointers into strings and load
   the converted string into the buffer. But the change to bstr_printf()
   had an off-by-one error and didn't account for the nul character at
   the end of the string and this corrupted the rest of the values in
   the format that came after a dereferenced pointer."

* tag 'trace-v4.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  vsprintf: Fix off-by-one bug in bstr_printf() processing dereferenced pointers

parents f7e59f38 62165600

lib/vsprintf.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2794,7 +2794,7 @@ int bstr_printf(char buf, size_t size, const char fmt, const u32 *bin_buf)
		copy = end - str;
		memcpy(str, args, copy);
		str += len;
		args += len;
		args += len + 1;
		}
		}
		if (process)

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