Re: DEBUG_LOCKS_WARN_ON(1) / lockdep.c:3134 lockdep_init_map+0x1e8/0x1f0

[Peter Zijlstra]

On Tue, Jan 03, 2017 at 06:11:20PM -0800, Christian Kujau wrote:
> Hi,
> 
> booting v4.10-rc2 on this PowerPC G4 machine prints the following early 
> on, but then continues to boot and the machine is running fine so far:
> 
> 
> BUG: key ef0ba7d0 not in .data!
> DEBUG_LOCKS_WARN_ON(1)
> [ cut here ]
> WARNING: CPU: 0 PID: 1 at 
> /usr/local/src/linux-git/kernel/locking/lockdep.c:3134 
> lockdep_init_map+0x1e8/0x1f0
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper Not tainted 4.10.0-rc2 #4
> task: ef04aa60 task.stack: ef042000
> NIP: c005eb78 LR: c005eb78 CTR: 
> REGS: ef043d70 TRAP: 0700   Not tainted  (4.10.0-rc2)
> MSR: 02029032 
>   CR: 4822  XER: 2000
> GPR00: c005eb78 ef043e20 ef04aa60 0016 0001 c0068b24  
> 0001 
> GPR08:   4ead 00d6 2824  c00047f0 
>  
> GPR16:   c08b9280 effedfa0 c078d6ac c107 c078eddc 
> c078ee14 
> GPR24: c078ed24 c078ee24 0002 ef085a00  c08b ef0ba7d0 
> ef0ba7b4 
> NIP [c005eb78] lockdep_init_map+0x1e8/0x1f0
> LR [c005eb78] lockdep_init_map+0x1e8/0x1f0
> Call Trace:
> [ef043e20] [c005eb78] lockdep_init_map+0x1e8/0x1f0 (unreliable)
> [ef043e40] [c083adb4] kw_i2c_add+0xc0/0x134


Commit 9e607f72748d ("i2c_powermac: shut up lockdep warning") it utter
crap and should never have been merged.

/me glares at mpe, why do you merge things that state: 'its unclear
why, just make it go-away' wrt to locking?

DEBUG_LOCKS_WARN_ON(1) / lockdep.c:3134 lockdep_init_map+0x1e8/0x1f0

[Christian Kujau]

Hi,

booting v4.10-rc2 on this PowerPC G4 machine prints the following early 
on, but then continues to boot and the machine is running fine so far:


BUG: key ef0ba7d0 not in .data!
DEBUG_LOCKS_WARN_ON(1)
[ cut here ]
WARNING: CPU: 0 PID: 1 at 
/usr/local/src/linux-git/kernel/locking/lockdep.c:3134 
lockdep_init_map+0x1e8/0x1f0
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.10.0-rc2 #4
task: ef04aa60 task.stack: ef042000
NIP: c005eb78 LR: c005eb78 CTR: 
REGS: ef043d70 TRAP: 0700   Not tainted  (4.10.0-rc2)
MSR: 02029032 
  CR: 4822  XER: 2000
GPR00: c005eb78 ef043e20 ef04aa60 0016 0001 c0068b24  0001 
GPR08:   4ead 00d6 2824  c00047f0  
GPR16:   c08b9280 effedfa0 c078d6ac c107 c078eddc c078ee14 
GPR24: c078ed24 c078ee24 0002 ef085a00  c08b ef0ba7d0 ef0ba7b4 
NIP [c005eb78] lockdep_init_map+0x1e8/0x1f0
LR [c005eb78] lockdep_init_map+0x1e8/0x1f0
Call Trace:
[ef043e20] [c005eb78] lockdep_init_map+0x1e8/0x1f0 (unreliable)
[ef043e40] [c083adb4] kw_i2c_add+0xc0/0x134
[ef043e60] [c083b29c] pmac_i2c_init+0x3b8/0x518
[ef043ea0] [c00040c0] do_one_initcall+0x40/0x174
[ef043f00] [c0834064] kernel_init_freeable+0x134/0x1cc
[ef043f30] [c0004808] kernel_init+0x18/0x110
[ef043f40] [c0010ad8] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
4837259d 2f83 41befec0 3d20c08b 812953a0 2f89 409efeb0 3c60c079 
3c80c07b 3884b48c 3863f9e4 4860d52d <0fe0> 4bfffe94 9421ff70 7c0802a6 
---[ end trace 8a79d8041d87d000 ]---


Full dmesg and .config: http://nerdbynature.de/bits/4.10-rc2/


Thanks for listening,
Christian.
-- 
BOFH excuse #409:

The vulcan-death-grip ping has been applied.