Hi all, I've got a real-time kernel on a DRA7 evaluation module (EVM). Very early in the boot process I get the following splat. [ 0.055073] [ 0.055076] =============================== [ 0.055079] [ INFO: suspicious RCU usage. ] [ 0.055084] 4.1.6+ #2 Not tainted [ 0.055086] ------------------------------- [ 0.055090] include/trace/events/hist.h:31 suspicious rcu_dereference_check() usage! [ 0.055093] [ 0.055093] other info that might help us debug this: [ 0.055093] [ 0.055097] [ 0.055097] RCU used illegally from idle CPU! [ 0.055097] rcu_scheduler_active = 1, debug_locks = 1 [ 0.055100] RCU used illegally from extended quiescent state! [ 0.055104] no locks held by swapper/0/0. [ 0.055106] [ 0.055106] stack backtrace: [ 0.055112] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.6+ #2 [ 0.055116] Hardware name: Generic DRA74X (Flattened Device Tree) [ 0.055130] [<c00196b8>] (unwind_backtrace) from [<c001515c>] (show_stack+0x20/0x24) [ 0.055146] [<c001515c>] (show_stack) from [<c07bc408>] (dump_stack+0x84/0xa0) [ 0.055160] [<c07bc408>] (dump_stack) from [<c009bc38>] (lockdep_rcu_suspicious+0xb0/0x110) [ 0.055172] [<c009bc38>] (lockdep_rcu_suspicious) from [<c01246c4>] (time_hardirqs_off+0x2b8/0x3c8) [ 0.055184] [<c01246c4>] (time_hardirqs_off) from [<c009a218>] (trace_hardirqs_off_caller+0x2c/0xf4) [ 0.055194] [<c009a218>] (trace_hardirqs_off_caller) from [<c009a2f4>] (trace_hardirqs_off+0x14/0x18) [ 0.055204] [<c009a2f4>] (trace_hardirqs_off) from [<c00c7ecc>] (rcu_idle_enter+0x78/0xcc) [ 0.055213] [<c00c7ecc>] (rcu_idle_enter) from [<c0093eb0>] (cpu_startup_entry+0x190/0x518) [ 0.055222] [<c0093eb0>] (cpu_startup_entry) from [<c07b95b4>] (rest_init+0x13c/0x17c) [ 0.055231] [<c07b95b4>] (rest_init) from [<c0b32c74>] (start_kernel+0x320/0x380) [ 0.055238] [<c0b32c74>] (start_kernel) from [<8000807c>] (0x8000807c) I'm not sure how to debug this; I'm still reading up on RCUs. Pretty nifty ideas. Looking at include/trace/events/hist.h it appears line 31 is the end of a TRACE_EVENT macro usage. Does that mean the macro is using RCU improperly somehow? Thanks, Philipp -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html