ftrace: Make all inline tags also include notrace
Commit 5963e317 ("ftrace/x86: Do not change stacks in DEBUG when calling lockdep") prevented lockdep calls from the int3 breakpoint handler from reseting the stack if a function that was called was in the process of being converted for tracing and had a breakpoint on it. The idea is, before calling the lockdep code, do a load_idt() to the special IDT that kept the breakpoint stack from reseting. This worked well as a quick fix for this kernel release, until a certain config caused a lockup in the function tracer start up tests. Investigating it, I found that the load_idt that was used to prevent the int3 from changing stacks was itself being traced! Even though the config had CONFIG_OPTIMIZE_INLINING disabled, and all 'inline' tags were set to always inline, there were still cases that it did not inline! This was caused by CONFIG_PARAVIRT_GUEST, where it would add a pointer to the native_load_idt() which made that function to be traced. Commit 45959ee7 ("ftrace: Do not function trace inlined functions") only touched the 'inline' tags when CONFIG_OPMITIZE_INLINING was enabled. PARAVIRT_GUEST shows that this was not enough and we need to also mark always_inline with notrace as well. Reported-by: Fengguang Wu <wfg@linux.intel.com> Tested-by: Fengguang Wu <wfg@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Showing
Please register or sign in to comment