entries in 116 pages [ 1.061000] ------------[ cut here ]------------ [ 1.061000] WARNING: at kernel/trace/ftrace.c:441 [...] [ 1.060000] ---[ end trace 4eaa2a86a8e2da23 ]--- [ 1.060000] ftrace failed to modify [] check_corruption+0x3/0x2d [ 1.060000] actual: 0f:1f:44:00:00 This warning shows that check_corruption+0x3 already had a nop in its place (0x0f1f440000). After compiling another kernel the problem went away. Later Eric Paris notice the same type of issue. Luckily, he saved the vmlinux file that caused it. In the file we found a bunch of duplicate mcount call site records, which lead us to the script. Perhaps this problem only happens to people named Eric. This patch changes the script to test if the __mcount_loc already exists in the object file, and if it does, it will print out an error message and kill the compile. Reported-by: Eric Sesterhenn Reported-by: Eric Paris Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar 梐