On Thu, 9 Apr 2020 06:06:35 -0400 Qian Cai <c...@lca.pw> wrote: > >> I’ll go to bisect some more but it is going to take a while. > >> > >> $ git log --oneline 4c205c84e249..8e99cf91b99b > >> 8e99cf91b99b tracing: Do not allocate buffer in trace_find_next_entry() in > >> atomic > >> 2ab2a0924b99 tracing: Add documentation on set_ftrace_notrace_pid and > >> set_event_notrace_pid > >> ebed9628f5c2 selftests/ftrace: Add test to test new set_event_notrace_pid > >> file > >> ed8839e072b8 selftests/ftrace: Add test to test new set_ftrace_notrace_pid > >> file > >> 276836260301 tracing: Create set_event_notrace_pid to not trace tasks > > > >> b3b1e6ededa4 ftrace: Create set_ftrace_notrace_pid to not trace tasks > >> 717e3f5ebc82 ftrace: Make function trace pid filtering a bit more exact > > > > If it is affecting function tracing, it is probably one of the above two > > commits. > > OK, it was narrowed down to one of those messed with mcount here,
Thing is, nothing here touches mcount. > > 8e99cf91b99b tracing: Do not allocate buffer in trace_find_next_entry() in > atomic Touches reading the trace buffer. > 2ab2a0924b99 tracing: Add documentation on set_ftrace_notrace_pid and > set_event_notrace_pid Documentation. > 6a13a0d7b4d1 ftrace/kprobe: Show the maxactive number on kprobe_events kprobe output. > c9b7a4a72ff6 ring-buffer/tracing: Have iterator acknowledge dropped events Reading the buffer. > 06e0a548bad0 tracing: Do not disable tracing when reading the trace file Reading the buffer. > 1039221cc278 ring-buffer: Do not disable recording when there is an iterator Reading the buffer. > 07b8b10ec94f ring-buffer: Make resize disable per cpu buffer instead of total > buffer Resizing the buffer. > 153368ce1bd0 ring-buffer: Optimize rb_iter_head_event() Reading the buffer. > ff84c50cfb4b ring-buffer: Do not die if rb_iter_peek() fails more than thrice Reading the buffer. > 785888c544e0 ring-buffer: Have rb_iter_head_event() handle concurrent writer Reading the buffer. > 28e3fc56a471 ring-buffer: Add page_stamp to iterator for synchronization Reading the buffer. > bc1a72afdc4a ring-buffer: Rename ring_buffer_read() to > read_buffer_iter_advance() Reading the buffer. > ead6ecfddea5 ring-buffer: Have ring_buffer_empty() not depend on tracing > stopped Reading the buffer. > ff895103a84a tracing: Save off entry when peeking at next entry Reading the buffer. > bf2cbe044da2 tracing: Use address-of operator on section symbols Affects trace_printk() > bbd9d05618a6 gpu/trace: add a gpu total memory usage tracepoint New tracepoint infrastructure (just new trace events for gpu) > 89b74cac7834 tools/bootconfig: Show line and column in parse error Extended command line boot config. > 306b69dce926 bootconfig: Support O=<builddir> option Extended command line boot config > 5412e0b763e0 tracing: Remove unused TRACE_BUFFER bits Removed unused enums. > b396bfdebffc tracing: Have hwlat ts be first instance and record count of > instances Affects only the hard ware latency detector (most likely not even configured in the kernel). So I don't understand how any of the above commits can cause a problem. -- Steve
