Re: Boot crash on 68030, was Re: [PATCH][M68K] implement futex.h to support userspace robust futexes and PI mutexes

[Mikael Pettersson <mikpelinux@gmail.com>]

Finn Thain writes:
 > 
 > On Tue, 10 Dec 2013, Andreas Schwab wrote:
 > 
 > > Finn Thain <fthain@telegraphics.com.au> writes:
 > > 
 > > > Data read fault at 0x00000000 in Super Data (pc=0x3afec)
 > > > BAD KERNEL BUSERR
 > > > Oops: 00000000
 > > > Modules linked in:
 > > > PC: [<0003afec>] cmpxchg_futex_value_locked+0x14/0x4a
 > > 
 > > What does it do here?
 > 
 > What happens next is that swapper dies leading to panic (see below).
 > 
 > It appears that the call graph looks like this,
 > 
 > futex_init()
 >   cmpxchg_futex_value_locked(&curval, NULL, 0, 0)
 >     pagefault_disable();
 >     futex_atomic_cmpxchg_inatomic(curval, NULL, 0, 0)
 >       get_user(val, NULL)
 > 
 > That is, futex_init() passes a NULL pointer expecting it to fault, as 
 > described in the comments in kernel/futex.c. Clearly the fault is not 
 > expected to be fatal.
 > 
 > Finn

Since it works for 040 I'd have to suspect some breakage in the
pagefault handling for 030.  However I haven't looked at that code
in any detail yet.

/Mikael

 > 
 > 
 > MacLinux
 > 
 >  vidaddr: 60040000
 >   _stext: 00001000
 > bootinfo: 002CC000
 >    cpuid: 00000000
 >  sccbase: 50F04000
 > 
 > ABCFGHIJK
 > Linux version 3.10.0-rc2-mac-111606-ge4f2dfb (fthain@nippy) (gcc version 
 > 4.4.6 (GCC) ) #14 Tue Dec 10 11:31:21 EST 2013
 > bootconsole [early0] enabled
 > Detected Macintosh model: 33
 > VIA1 at 50f00000 is a 6522 or clone
 > VIA2 at 50f02000 is a 6522 or clone
 > Apple Macintosh PowerBook 180
 > Built 1 zonelists in Zone order, mobility grouping off.  Total pages: 3045
 > Kernel command line: console=ttyS0
 > PID hash table entries: 64 (order: -4, 256 bytes)
 > Dentry cache hash table entries: 2048 (order: 1, 8192 bytes)
 > Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)
 > Sorting __ex_table...
 > Memory: 9252k/9252k available (1948k kernel code, 984k data, 104k init)
 > Virtual kernel memory layout:
 >     vector  : 0x0029318c - 0x0029358c   (   1 KiB)
 >     kmap    : 0xd0000000 - 0xf0000000   ( 512 MiB)
 >     vmalloc : 0x01000000 - 0xd0000000   (3312 MiB)
 >     lowmem  : 0x00000000 - 0x00c00000   (  12 MiB)
 >       .init : 0x002b2000 - 0x002cc000   ( 104 KiB)
 >       .text : 0x00001000 - 0x001e71aa   (1945 KiB)
 >       .data : 0x001e9d60 - 0x002b11d0   ( 798 KiB)
 >       .bss  : 0x00292f80 - 0x002b11d0   ( 121 KiB)
 > SLUB: HWalign=16, Order=0-3, MinObjects=0, CPUs=1, Nodes=8
 > NR_IRQS:72
 > Killing onboard sonic... Done.
 > WARNING: Persistent clock returned invalid value!
 >          Check your CMOS/BIOS settings.
 > Console: colour dummy device 80x25
 > console [ttyS0] enabled, bootconsole disabled
 > console [ttyS0] enabled, bootconsole disabled
 > Calibrating delay loop... 7.83 BogoMIPS (lpj=39168)
 > pid_max: default: 32768 minimum: 301
 > Mount-cache hash table entries: 512
 > devtmpfs: initialized
 > NET: Registered protocol family 16
 > bio: create slab <bio-0> at 0
 > NuBus: Scanning NuBus slots.
 > SCSI subsystem initialized
 > NET: Registered protocol family 2
 > TCP established hash table entries: 512 (order: 0, 4096 bytes)
 > TCP bind hash table entries: 512 (order: -1, 2048 bytes)
 > TCP: Hash tables configured (established 512 bind 512)
 > TCP: reno registered
 > UDP hash table entries: 256 (order: 0, 4096 bytes)
 > UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
 > NET: Registered protocol family 1
 > RPC: Registered named UNIX socket transport module.
 > RPC: Registered udp transport module.
 > RPC: Registered tcp transport module.
 > RPC: Registered tcp NFSv4.1 backchannel transport module.
 > Data read fault at 0x00000000 in Super Data (pc=0x3afec)
 > BAD KERNEL BUSERR
 > Oops: 00000000
 > Modules linked in:
 > PC: [<0003afec>] cmpxchg_futex_value_locked+0x14/0x4a
 > SR: 2004  SP: 0082fed4  a2: 0082c000
 > d0: 00000000    d1: 00000001    d2: 00000018    d3: 00000000
 > d4: 00000061    d5: 00001000    a0: 00000000    a1: 0082e000
 > Process swapper (pid: 1, task=0082c000)
 > Frame format=B ssw=074d isc=4a80 isb=661c daddr=00000000 dobuf=00000001
 > baddr=0003aff2 dibuf=00000000 ver=f
 > Stack from 0082ff5c:
 >         002b8cb8 0082ff70 00000000 00000000 00000000 00000000 00000000 000020ac
 >         00000018 00000007 00000061 00001000 00000000 00000000 002cab50 00002008
 >         002b3a56 002b8ca4 0082c3f0 00000000 0082c53c 001e316a 00000000 00000000
 >         001e3172 001e316a 000025d4 00000000 00000000 00000000 00000000 00000000
 >         00000000 00000000 00000000 00000000 00000000 00000000 00000000 20000000
 >         00000000
 > Call Trace: [<002b8cb8>] futex_init+0x14/0x54
 >  [<000020ac>] do_one_initcall+0xa4/0x144
 >  [<00001000>] kernel_pg_dir+0x0/0x1000
 >  [<00002008>] do_one_initcall+0x0/0x144
 >  [<002b3a56>] kernel_init_freeable+0xca/0x152
 >  [<002b8ca4>] futex_init+0x0/0x54
 >  [<001e316a>] kernel_init+0x0/0xc8
 >  [<001e3172>] kernel_init+0x8/0xc8
 >  [<001e316a>] kernel_init+0x0/0xc8
 >  [<000025d4>] ret_from_kernel_thread+0xc/0x14
 > 
 > Code: 200f 0280 ffff e000 2240 52a9 0010 4280 <0e90> 1000 4a80 661c b2af 
 > 000c 660c 226f 0010 0e90 9800 4a80 660a 206f 0004 2081
 > Disabling lock debugging due to kernel taint
 > note: swapper[1] exited with preempt_count 1
 > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

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