On 04/08/2014 10:59 AM, Steven Rostedt wrote: > On Tue, 08 Apr 2014 10:26:56 -0400 > Sasha Levin <[email protected]> wrote: > >> Hi all, >> >> While fuzzing with trinity inside a KVM tools guest running the latest -next >> kernel, I've stumbled on the following: >> >> [ 2983.109380] WARNING: CPU: 0 PID: 744 at kernel/trace/ftrace.c:1704 >> ftrace_bug+0xb0/0x280() >> [ 2983.110893] Modules linked in: >> [ 2983.111439] CPU: 0 PID: 744 Comm: trinity-main Tainted: G W >> 3.14.0-next-20140407-sasha-00023-gd35b0d6 #382 > > What was the warning before this?
There was nothing before that in both cases I've seen this issue. >> [ 2983.112845] 0000000000000009 ffff88002c4e3b88 ffffffffa252ee51 >> 0000000000002420 >> [ 2983.113993] 0000000000000000 ffff88002c4e3bc8 ffffffff9f15a2dc >> ffffffff9fffffc0 >> [ 2983.115134] ffff88018aaad530 ffffffffa0000000 000000000000ad53 >> ffffffffa6486e10 >> [ 2983.116221] Call Trace: >> [ 2983.116603] dump_stack (lib/dump_stack.c:52) >> [ 2983.117306] warn_slowpath_common (kernel/panic.c:419) >> [ 2983.118252] ? nva3_ram_prog >> (drivers/gpu/drm/nouveau/core/subdev/fb/ramnva3.c:318) >> [ 2983.119091] ? nva3_ram_tidy >> (drivers/gpu/drm/nouveau/core/subdev/fb/ramnva3.c:326) >> [ 2983.119836] ? __fentry__ (arch/x86/kernel/entry_64.S:106) >> [ 2983.121379] warn_slowpath_null (kernel/panic.c:454) >> [ 2983.122635] ftrace_bug (kernel/trace/ftrace.c:1704 (discriminator 3)) >> [ 2983.123688] ftrace_replace_code (arch/x86/kernel/ftrace.c:625 >> (discriminator 3)) >> [ 2983.124938] ftrace_modify_all_code (kernel/trace/ftrace.c:2011) >> [ 2983.126208] arch_ftrace_update_code (arch/x86/include/asm/atomic.h:103 >> arch/x86/kernel/ftrace.c:680) >> [ 2983.127613] ftrace_run_update_code (kernel/trace/ftrace.c:2088) >> [ 2983.128540] ftrace_startup_enable (kernel/trace/ftrace.c:2114) >> [ 2983.129392] ftrace_startup (kernel/trace/ftrace.c:2146) >> [ 2983.130679] register_ftrace_function (kernel/trace/ftrace.c:4864) >> [ 2983.131667] perf_ftrace_event_register >> (kernel/trace/trace_event_perf.c:356) >> [ 2983.132590] perf_trace_init (kernel/trace/trace_event_perf.c:187 >> kernel/trace/trace_event_perf.c:206) >> [ 2983.133377] ? __lock_is_held (kernel/locking/lockdep.c:3516) >> [ 2983.134181] perf_tp_event_init (kernel/events/core.c:5937) >> [ 2983.135043] perf_init_event (kernel/events/core.c:6598) >> [ 2983.135882] ? perf_pmu_unregister (kernel/events/core.c:6577) >> [ 2983.136803] perf_event_alloc (kernel/events/core.c:6754) >> [ 2983.137831] SYSC_perf_event_open (kernel/events/core.c:7062) >> [ 2983.138798] ? preempt_count_sub (kernel/sched/core.c:2526) >> [ 2983.139643] ? context_tracking_user_exit >> (arch/x86/include/asm/paravirt.h:809 (discriminator 2) >> kernel/context_tracking.c:182 (discriminator 2)) >> [ 2983.140912] ? context_tracking_user_exit >> (arch/x86/include/asm/paravirt.h:809 (discriminator 2) >> kernel/context_tracking.c:182 (discriminator 2)) >> [ 2983.141941] SyS_perf_event_open (kernel/events/core.c:6990) >> [ 2983.142771] tracesys (arch/x86/kernel/entry_64.S:749) >> [ 2983.144740] ---[ end trace 6321065f5978f85b ]--- >> [ 2983.145355] ftrace failed to modify nva3_ram_init >> (drivers/gpu/drm/nouveau/core/subdev/fb/ramnva3.c:326) >> [ 2983.146357] actual: 90:66:66:66:90 > > Hmm, I wonder what the "ideal" nop is on this machine. But I think it > should probably have been 66:66:66:66:90? > > Is this reproducible? It happened twice during the overnight fuzzing session, so while I can't force it to happen again I'm assuming that it'll show up again if we wait enough. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
