linux/arch/s390
Christian Borntraeger 2944a5c971 [S390] pgtable.h: Fix oops in unmap_vmas for KVM processes
When running several kvm processes with lots of memory overcommitment,
we have seen an oops during process shutdown:
------------[ cut here ]------------
Kernel BUG at 0000000000193434 [verbose debug info unavailable]
addressing exception: 0005 [#1] PREEMPT SMP
Modules linked in: kvm sunrpc qeth_l2 dm_mod qeth ccwgroup
CPU: 10 Not tainted 2.6.28-rc4-kvm-bigiron-00521-g0ccca08-dirty #8
Process kuli (pid: 14460, task: 0000000149822338, ksp: 0000000024f57650)
Krnl PSW : 0704e00180000000 0000000000193434 (unmap_vmas+0x884/0xf10)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 EA:3
Krnl GPRS: 0000000000000002 0000000000000000 000000051008d000 000003e05e6034e0
           00000000001933f6 00000000000001e9 0000000407259e0a 00000002be88c400
           00000200001c1000 0000000407259608 0000000407259e08 0000000024f577f0
           0000000407259e09 0000000000445fa8 00000000001933f6 0000000024f577f0
Krnl Code: 0000000000193426: eb22000c000d sllg %r2,%r2,12
           000000000019342c: a7180000 lhi %r1,0
           0000000000193430: b2290012 iske %r1,%r2
          >0000000000193434: a7110002 tmll %r1,2
           0000000000193438: a7840006 brc 8,193444
           000000000019343c: 9602c000 oi 0(%r12),2
           0000000000193440: 96806000 oi 0(%r6),128
           0000000000193444: a7110004 tmll %r1,4
Call Trace:
([<00000000001933f6>] unmap_vmas+0x846/0xf10)
[<0000000000199680>] exit_mmap+0x210/0x458
[<000000000012a8f8>] mmput+0x54/0xfc
[<000000000012f714>] exit_mm+0x134/0x144
[<000000000013120c>] do_exit+0x240/0x878
[<00000000001318dc>] do_group_exit+0x98/0xc8
[<000000000013e6b0>] get_signal_to_deliver+0x30c/0x358
[<000000000010bee0>] do_signal+0xec/0x860
[<0000000000112e30>] sysc_sigpending+0xe/0x22
[<000002000013198a>] 0x2000013198a
INFO: lockdep is turned off.
Last Breaking-Event-Address:
[<00000000001a68d0>] free_swap_and_cache+0x1a0/0x1a4
<4>---[ end trace bc19f1d51ac9db7c ]---

The faulting instruction is the storage key operation (iske) in
ptep_rcp_copy (called by pte_clear, called by unmap_vmas). iske
reads dirty and reference bit information for a physical page and
requires a valid physical address. Since we are in pte_clear, we
cannot rely on the pte containing a valid address. Fortunately we
dont need these information in pte_clear - after all there is no
mapping. The best fix is to remove the needless call to ptep_rcp_copy
that contains the iske.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-11-27 11:06:57 +01:00
..
appldata [S390] appldata: unsigned ops->size cannot be negative 2008-10-28 11:12:04 +01:00
boot [PATCH] use ${CROSS_COMPILE}installkernel in arch/*/boot/install.sh 2005-06-23 09:45:07 -07:00
crypto Merge branch 'bkl-removal' of git://git.lwn.net/linux-2.6 2008-07-14 14:48:31 -07:00
hypfs vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
include/asm [S390] pgtable.h: Fix oops in unmap_vmas for KVM processes 2008-11-27 11:06:57 +01:00
kernel [S390] fix/cleanup sched_clock 2008-11-27 11:06:57 +01:00
kvm KVM: s390: Make facility bits future-proof 2008-10-15 10:15:24 +02:00
lib [S390] Move private simple udelay function to arch/s390/lib/delay.c. 2008-10-10 21:33:58 +02:00
math-emu [S390] remove -traditional 2008-04-30 13:38:44 +02:00
mm [S390] pgtables: Fix race in enable_sie vs. page table ops 2008-10-28 11:12:03 +01:00
oprofile Combine instrumentation menus in kernel/Kconfig.instrumentation 2007-10-19 11:53:54 -07:00
defconfig [S390] Update default configuration. 2008-08-21 19:46:42 +02:00
Kconfig [S390] No more 4kb stacks. 2008-10-28 11:12:06 +01:00
Kconfig.debug [S390] DEBUG_PAGEALLOC support for s390. 2008-02-05 16:50:54 +01:00
Makefile KVM: s390: arch backend for the kvm kernel module 2008-04-27 12:00:42 +03:00