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| author | Carsten Otte <cotte@de.ibm.com> | 2008-06-10 12:03:22 +0400 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2008-06-10 12:03:27 +0400 |
| commit | 7b439d25300dc59bba76b53eb344bb9e5a1133f2 (patch) | |
| tree | 256f964770666de869c621d422acf702126b9d63 /drivers/s390/char/sclp_vt220.c | |
| parent | 85b0d7c0ad92c47887bf6aeb424a14e7af14bd87 (diff) | |
| download | linux-7b439d25300dc59bba76b53eb344bb9e5a1133f2.tar.xz | |
[S390] vt220 console, initialize list head before use
This patch fixes a null pointer dereference during initialisation when no
sclp event facility is available:
sclp vt220 tty driver: could not register vt220 - sclp_register returned -5
Unable to handle kernel paging request at virtual user address 0000000000000000
Oops: 0004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 Not tainted 2.6.26-rc3-kvm-bigiron-00968-gd939e93-dirty #30
Process swapper (pid: 0, task: 0000000000600be0, ksp: 000000000064a000)
Krnl PSW : 0400000180000000 0000000000320d8c (sclp_unregister+0x48/0x8c)
R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3
Krnl GPRS: 0000000000000000 0000000000000000 0000000000630478 0700000000649c20
0000000000000000 0000000000433060 000000000064a660 0000000002e26000
00000000006db000 0000000000000000 0000000000a78578 0000000000649b80
0000000000630dc0 000000000044fa20 0000000000320d76 0000000000649b80
Krnl Code: 0000000000320d7c: e310c0080004 lg %r1,8(%r12)
0000000000320d82: b9040032 lgr %r3,%r2
0000000000320d86: c02000187b79 larl %r2,630478
>0000000000320d8c: e34010000024 stg %r4,0(%r1)
0000000000320d92: e31040080024 stg %r1,8(%r4)
0000000000320d98: c01100200200 lgfi %r1,2097664
0000000000320d9e: e310c0080024 stg %r1,8(%r12)
0000000000320da4: c01100100100 lgfi %r1,1048832
Call Trace:
([<0000000000320d76>] sclp_unregister+0x32/0x8c)
[<00000000006657b4>] __sclp_vt220_cleanup+0xc4/0xe0
[<000000000066595c>] __sclp_vt220_init+0x18c/0x1a0
[<0000000000665aba>] sclp_vt220_con_init+0x42/0x68
[<00000000006601ca>] console_init+0x4e/0x68
[<000000000064acae>] start_kernel+0x3a2/0x4dc
[<0000000000100020>] _stext+0x20/0x80
INFO: lockdep is turned off.
Last Breaking-Event-Address:
[<000000000041f964>] _spin_lock_irqsave+0xb0/0xb4
<4>---[ end trace 31fd0ba7d8756001 ]---
The issue is caused by a list_empty() check in __sclp_vt220_cleanup, which
usually fails on non-initialized list heads that contain {NULL,NULL} instead.
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/char/sclp_vt220.c')
| -rw-r--r-- | drivers/s390/char/sclp_vt220.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index 62576af36f47..3e577f655b18 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -773,6 +773,7 @@ sclp_vt220_con_init(void) { int rc; + INIT_LIST_HEAD(&sclp_vt220_register.list); if (!CONSOLE_IS_SCLP) return 0; rc = __sclp_vt220_init(); |