[3.1] lockdep scheduling while atomic on boot
From: Simon Kirby
Date: Wed Oct 26 2011 - 20:06:11 EST
We were messing with initrd stuff to get root on MD to work with newer
than original MD superblock versions (grumble), and threw a lockdep
kernel on, which spat out the following during boot:
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Linux version 3.1.0-hw-lockdep+ (root@packages01-dev) (gcc version 4.3.2 (Debian 4.3.2-1.1) ) #54 SMP Wed Oct 26 14:25:58 CDT 2011
[ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.1.0-hw-lockdep+ root=UUID=5c132cc5-ec54-4155-aa8d-ab1834b58eee ro quiet
...
[ 0.004146] Mount-cache hash table entries: 256
[ 0.004999] Initializing cgroup subsys blkio
[ 0.005087] CPU: Physical Processor ID: 0
[ 0.005090] CPU: Processor Core ID: 0
[ 0.005092] mce: CPU supports 6 MCE banks
[ 0.005099] CPU0: Thermal monitoring enabled (TM1)
[ 0.005104] using mwait in idle threads.
[ 0.009021] ACPI: Core revision 20110623
[ 0.009157] BUG: scheduling while atomic: swapper/0/0x10000002
[ 0.009217] no locks held by swapper/0.
[ 0.009219] Modules linked in:
[ 0.009223] Pid: 0, comm: swapper Not tainted 3.1.0-hw-lockdep+ #54
[ 0.009225] Call Trace:
[ 0.009234] [<ffffffff81051475>] __schedule_bug+0x85/0x90
[ 0.009240] [<ffffffff816f5305>] __schedule+0x795/0xa20
[ 0.009245] [<ffffffff81096c3d>] ? trace_hardirqs_on_caller+0x13d/0x1c0
[ 0.009250] [<ffffffff81126a89>] ? kmem_cache_free+0x159/0x190
[ 0.009254] [<ffffffff813da692>] ? acpi_os_release_object+0x9/0xd
[ 0.009258] [<ffffffff81096c3d>] ? trace_hardirqs_on_caller+0x13d/0x1c0
[ 0.009261] [<ffffffff81096ccd>] ? trace_hardirqs_on+0xd/0x10
[ 0.009265] [<ffffffff813da692>] ? acpi_os_release_object+0x9/0xd
[ 0.009269] [<ffffffff813f8340>] ? acpi_ps_free_op+0x22/0x24
[ 0.009273] [<ffffffff81059335>] __cond_resched+0x25/0x40
[ 0.009277] [<ffffffff816f561d>] _cond_resched+0x2d/0x40
[ 0.009280] [<ffffffff813f75e8>] acpi_ps_complete_op+0x258/0x26e
[ 0.009284] [<ffffffff813f7e54>] acpi_ps_parse_loop+0x856/0x9ae
[ 0.009287] [<ffffffff813f6f2d>] acpi_ps_parse_aml+0x9a/0x282
[ 0.009291] [<ffffffff813f55bc>] acpi_ns_one_complete_parse+0xfc/0x117
[ 0.009295] [<ffffffff813f55f3>] acpi_ns_parse_table+0x1c/0x35
[ 0.009298] [<ffffffff813f2d1a>] acpi_ns_load_table+0x4a/0x8c
[ 0.009302] [<ffffffff813f9e1b>] acpi_load_tables+0xa0/0x164
[ 0.009307] [<ffffffff81b0dbe9>] ? acpi_initialize_subsystem+0x84/0xac
[ 0.009310] [<ffffffff81b0c8db>] acpi_early_init+0x6c/0xf7
[ 0.009315] [<ffffffff81ae0ca5>] start_kernel+0x370/0x43e
[ 0.009320] [<ffffffff81af77ba>] ? memblock_x86_reserve_range+0x2f/0x80
[ 0.009323] [<ffffffff81ae02c5>] x86_64_start_reservations+0xa5/0xc9
[ 0.009327] [<ffffffff81ae03f8>] x86_64_start_kernel+0x10f/0x12a
[ 0.009331] [<ffffffff81ae0140>] ? early_idt_handlers+0x140/0x140
[ 0.012520] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.053354] CPU0: Intel(R) Pentium(R) Dual CPU E2220 @ 2.40GHz stepping 0d
[ 0.056003] Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver.
[ 0.056003] PEBS disabled due to CPU errata.
[ 0.056003] ... version: 2
[ 0.056003] ... bit width: 40
[ 0.056003] ... generic registers: 2
[ 0.056003] ... value mask: 000000ffffffffff
[ 0.056003] ... max period: 000000007fffffff
[ 0.056003] ... fixed-purpose events: 3
[ 0.056003] ... event mask: 0000000700000003
[ 0.056003] NMI watchdog enabled, takes one hw-pmu counter.
[ 0.056003] lockdep: fixing up alternatives.
[ 0.056003] Booting Node 0, Processors #1
[ 0.056003] smpboot cpu 1: start_ip = 9c000
[ 0.144097] NMI watchdog enabled, takes one hw-pmu counter.
[ 0.144159] Brought up 2 CPUs
It still seems to work regardless of this BUG(). This didn't happen
without lockdep, so I assume it has something to do with how lockdep
checks are happening during early boot.
Dell r200; config, acidump, and full dmesg here: 0x.ca/sim/ref/3.1/
Simon-
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