• Steven Rostedt's avatar
    ftrace: Make all inline tags also include notrace · 93b3cca1
    Steven Rostedt authored
    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: default avatarFengguang Wu <wfg@linux.intel.com>
    Tested-by: default avatarFengguang Wu <wfg@linux.intel.com>
    Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
    93b3cca1
compiler-gcc.h 3.88 KB