Messages in this thread | | | Date | Mon, 21 Apr 2008 17:13:31 +0200 | From | "Vegard Nossum" <> | Subject | Re: [Bug 10489] Kprobe smoke test lockdep warning |
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On Mon, Apr 21, 2008 at 5:06 PM, Adrian Bunk <bunk@kernel.org> wrote: > http://bugzilla.kernel.org/show_bug.cgi?id=10489 > > Please reply via email (more information from the submitter is in the > Bugzilla entry). > > > ReportedBy: jeanmarc.lacroix@free.Fr > > Earliest failing kernel version: 2.6.25 > Distribution: DEbian Etch > Hardware Environment: PIII > Software Environment: > Problem Description: Warning at boot after running all > embedded test > > Steps to reproduce: boot !!! > > > 2.701005] Registering sys device '<NULL>' > [ 2.702320] Registering sys device '<NULL>' > [ 2.703711] Registering sys device '<NULL>' > [ 2.704536] Initializing RT-Tester: OK > [ 2.704824] device: 'snapshot': device_add > [ 2.705140] PM: Adding info for No Bus:snapshot > [ 2.706804] audit: initializing netlink socket (disabled) > [ 2.707199] type=2000 audit(1208713807.707:1): initialized > [ 2.707509] Kprobe smoke test started > [ 2.709300] ------------[ cut here ]------------ > [ 2.709420] WARNING: at kernel/lockdep.c:2658 check_flags+0x4d/0x12c() > [ 2.709541] Modules linked in: > [ 2.709588] Pid: 1, comm: swapper Not tainted 2.6.25.jml.057 #1 > [ 2.709588] [<c0126acc>] warn_on_slowpath+0x41/0x51 > [ 2.709588] [<c010bafc>] ? save_stack_trace+0x1d/0x3b > [ 2.709588] [<c0140a83>] ? save_trace+0x37/0x89 > [ 2.709588] [<c011987d>] ? kernel_map_pages+0x103/0x11c > [ 2.709588] [<c0109803>] ? native_sched_clock+0xca/0xea > [ 2.709588] [<c0142958>] ? mark_held_locks+0x41/0x5c > [ 2.709588] [<c0382580>] ? kprobe_exceptions_notify+0x322/0x3af > [ 2.709588] [<c0142aff>] ? trace_hardirqs_on+0xf1/0x119 > [ 2.709588] [<c03825b3>] ? kprobe_exceptions_notify+0x355/0x3af > [ 2.709588] [<c0140823>] check_flags+0x4d/0x12c > [ 2.709588] [<c0143c9d>] lock_release+0x58/0x195 > [ 2.709588] [<c038347c>] ? __atomic_notifier_call_chain+0x0/0x80 > [ 2.709588] [<c03834d6>] __atomic_notifier_call_chain+0x5a/0x80 > [ 2.709588] [<c0383508>] atomic_notifier_call_chain+0xc/0xe > [ 2.709588] [<c013b6d4>] notify_die+0x2d/0x2f > [ 2.709588] [<c038168a>] do_debug+0x67/0xfe > [ 2.709588] [<c0381287>] debug_stack_correct+0x27/0x30 > [ 2.709588] [<c01564c0>] ? kprobe_target+0x1/0x34 > [ 2.709588] [<c0156572>] ? init_test_probes+0x50/0x186 > [ 2.709588] [<c04fae48>] init_kprobes+0x85/0x8c > [ 2.709588] [<c04e947b>] kernel_init+0x13d/0x298 > [ 2.709588] [<c04e933e>] ? kernel_init+0x0/0x298 > [ 2.709588] [<c04e933e>] ? kernel_init+0x0/0x298 > [ 2.709588] [<c0105ef7>] kernel_thread_helper+0x7/0x10 > [ 2.709588] ======================= > [ 2.709588] ---[ end trace 778e504de7e3b1e3 ]--- > [ 2.709588] possible reason: unannotated irqs-off. > [ 2.709588] irq event stamp: 370065 > [ 2.709588] hardirqs last enabled at (370065): [<c0382580>] > kprobe_exceptions_notify+0x322/0x3af > [ 2.709588] hardirqs last disabled at (370064): [<c0381bb7>] > do_int3+0x1d/0x7d > [ 2.709588] softirqs last enabled at (370050): [<c012b464>] > __do_softirq+0xfa/0x100 > [ 2.709588] softirqs last disabled at (370045): [<c0107438>] > do_softirq+0x74/0xd9 > [ 2.714751] Kprobe smoke test passed successfully > [ 2.716150] Total HugeTLB memory allocated, 0 > [ 2.717288] VFS: Disk quotas dquot_6.5.1 > [ 2.717689] Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) > [ 2.719630] device class 'bsg': registering > [ 2.720568] Block layer SCSI generic (bsg) driver version 0.4 loaded (major > 253) > [ 2.720619] io scheduler noop registered > [ 2.720732] io scheduler anticipatory registered > [ 2.720848] io scheduler deadline registered > [ 2.721089] io scheduler cfq registered (default) > [ 2.721354] pci 0000:00:01.0: Boot video device >
This is because kprobes (just like kmemcheck and mmiotrace) needs to disable interrupts while it single-steps the instruction. This is not dangerous, and should be fixed by doing as the warning suggests, by annotating the irqs-off. I don't remember the name of the function(s), it is probably somewhere in lockdep.h.
Vegard
-- "The animistic metaphor of the bug that maliciously sneaked in while the programmer was not looking is intellectually dishonest as it disguises that the error is the programmer's own creation." -- E. W. Dijkstra, EWD1036
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