FYI, a recent tracing change causes this new warning on latest -tip: Freeing SMP alternatives: 20k freed ftrace: allocating 14134 entries in 28 pages ------------[ cut here ]------------ WARNING: at kernel/trace/ftrace.c:1006 ftrace_bug+0x94/0x1f9() Hardware name: System Product Name Modules linked in: Pid: 0, comm: swapper Not tainted 2.6.36-rc8-tip+ #49604 Call Trace: [] warn_slowpath_common+0x6a/0x7f [] ? ftrace_bug+0x94/0x1f9 [] ? ftrace_process_locs+0x152/0x225 [] warn_slowpath_null+0x14/0x18 [] ftrace_bug+0x94/0x1f9 [] ftrace_process_locs+0x17e/0x225 [] ? ftrace_process_locs+0x152/0x225 [] ftrace_init+0x112/0x12a [] start_kernel+0x287/0x291 [] i386_start_kernel+0x79/0x7b ---[ end trace 4eaa2a86a8e2da22 ]--- ftrace failed to modify [] ftrace_process_locs+0x152/0x225 actual: b9:44:2b:00:c1 Enabling APIC mode: Flat. Using 1 I/O APICs enabled ExtINT on CPU#0 (it booted up fine after this) Candidates would be: 0fdf136: Merge branch 'tip/perf/recordmcount-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core cf4db25: ftrace: Rename config option HAVE_C_MCOUNT_RECORD to HAVE_C_RECORDMCOUNT d9d572a: Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/core c28d507: ftrace: Remove duplicate code for 64 and 32 bit in recordmcount.c 72441cb: ftrace/x86: Add support for C version of recordmcount 81d3858: ftrace: Add C version of recordmcount compile time code ebc8827: x86: Barf when vmalloc and kmemcheck faults happen in NMI 3cba11d: kconfig/x86: Add HAVE_TEXT_POKE_SMP config for stop_machine dependency 3caa375: x86: Use __stop_machine() in text_poke_smp() 087a4eb: stopmachine: Define __stop_machine when CONFIG_STOP_MACHINE=n fd02e6f: kprobes: Fix selftest to clear flags field for reusing probes 0f55a2f: kprobes: Update document about irq disabled state in kprobe handler Config attached. Gut feeling suggests that it's the new in-C recordmcount code causing this bug. Thanks, Ingo