vsprintf: Introduce %pB format specifier

The %pB format specifier is for stack backtrace. Its handler
sprint_backtrace() does symbol lookup using (address-1) to
ensure the address will not point outside of the function.

If there is a tail-call to the function marked "noreturn",
gcc optimized out the code after the call then causes saved
return address points outside of the function (i.e. the start
of the next function), so pollutes call trace somewhat.

This patch adds the %pB printk mechanism that allows architecture
call-trace printout functions to improve backtrace printouts.

Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Steven Rostedt <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions