On Tue, 08 Apr 2014 11:02:07 -0400 Sasha Levin <[email protected]> wrote:
> 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. I believe the "W" taint means there was a previous warning. > > >> [ 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. Is it always the same function that fails? (I would highly doubt it would be). Also, do you have any idea of what the sequence of events that were performed was? -- Steve -- 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/
