1. 25 Jun, 2019 1 commit
    • Miguel Ojeda's avatar
      tracing: Silence GCC 9 array bounds warning · c64cefcb
      Miguel Ojeda authored
      commit 0c97bf86 upstream.
      
      Starting with GCC 9, -Warray-bounds detects cases when memset is called
      starting on a member of a struct but the size to be cleared ends up
      writing over further members.
      
      Such a call happens in the trace code to clear, at once, all members
      after and including `seq` on struct trace_iterator:
      
          In function 'memset',
              inlined from 'ftrace_dump' at kernel/trace/trace.c:8914:3:
          ./include/linux/string.h:344:9: warning: '__builtin_memset' offset
          [8505, 8560] from the object at 'iter' is out of the bounds of
          referenced subobject 'seq' with type 'struct trace_seq' at offset
          4368 [-Warray-bounds]
            344 |  return __builtin_memset(p, c, size);
                |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
      
      In order to avoid GCC complaining about it, we compute the address
      ourselves by adding the offsetof distance instead of referring
      directly to the member.
      
      Since there are two places doing this clear (trace.c and trace_kdb.c),
      take the chance to move the workaround into a single place in
      the internal header.
      
      Link: http://lkml.kernel.org/r/20190523124535.GA12931@gmail.comSigned-off-by: default avatarMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
      [ Removed unnecessary parenthesis around "iter" ]
      Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c64cefcb
  2. 22 Jun, 2019 39 commits