From 569309b42fc67a8b42f57adb68764bd10bcf2178 Mon Sep 17 00:00:00 2001 From: Aaro Koskinen Date: Fri, 17 Oct 2014 18:10:26 +0300 Subject: [PATCH] MIPS: oprofile: Backtrace: don't fail on leaf functions Continue the backtrace if we cannot find SP adjustment and RA save. In that case, just assume the current RA. This allows us to get samples of frequent callers of e.g. GLIBC memset(). Signed-off-by: Aaro Koskinen Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8109/ Signed-off-by: Ralf Baechle --- arch/mips/oprofile/backtrace.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/mips/oprofile/backtrace.c b/arch/mips/oprofile/backtrace.c index 83a1dfd8f0e3..5e645c9a3162 100644 --- a/arch/mips/oprofile/backtrace.c +++ b/arch/mips/oprofile/backtrace.c @@ -65,7 +65,7 @@ static inline int is_end_of_function_marker(union mips_instruction *ip) * - handle cases where the stack is adjusted inside a function * (generally doesn't happen) * - find optimal value for max_instr_check - * - try to find a way to handle leaf functions + * - try to find a better way to handle leaf functions */ static inline int unwind_user_frame(struct stackframe *old_frame, @@ -104,7 +104,7 @@ static inline int unwind_user_frame(struct stackframe *old_frame, } if (!ra_offset || !stack_size) - return -1; + goto done; if (ra_offset) { new_frame.ra = old_frame->sp + ra_offset; @@ -121,6 +121,7 @@ static inline int unwind_user_frame(struct stackframe *old_frame, if (new_frame.sp > old_frame->sp) return -2; +done: new_frame.pc = old_frame->ra; *old_frame = new_frame; -- 2.20.1