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authorHeiko Carstens <heiko.carstens@de.ibm.com>2011-05-26 09:48:29 +0200
committerHeiko Carstens <heiko.carstens@de.ibm.com>2011-05-26 09:48:25 +0200
commit99583181cbf2252dd0554eef6f419a6b22cd33ea (patch)
treebb8ff8673b3415318236a6efe0a8c5081ef32815 /arch/s390
parentb396637841fff79e9520514e8dcbe769c20a2ea0 (diff)
downloadop-kernel-dev-99583181cbf2252dd0554eef6f419a6b22cd33ea.zip
op-kernel-dev-99583181cbf2252dd0554eef6f419a6b22cd33ea.tar.gz
[S390] mm: handle kernel caused page fault oom situations
If e.g. copy_from_user() generates a page fault and the kernel runs into an OOM situation the system might lock up. If the OOM killer sends a SIG_KILL to the current process it can't handle it since it is stuck in a copy_from_user() - page fault loop. Fix this by adding the same fix as other architectures have. E.g. the x86 variant f86268 "x86/mm: Handle mm_fault_error() in kernel space" Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/mm/fault.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 105fa10..b57723a 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -245,9 +245,12 @@ static noinline void do_fault_error(struct pt_regs *regs, long int_code,
do_no_context(regs, int_code, trans_exc_code);
break;
default: /* fault & VM_FAULT_ERROR */
- if (fault & VM_FAULT_OOM)
- pagefault_out_of_memory();
- else if (fault & VM_FAULT_SIGBUS) {
+ if (fault & VM_FAULT_OOM) {
+ if (!(regs->psw.mask & PSW_MASK_PSTATE))
+ do_no_context(regs, int_code, trans_exc_code);
+ else
+ pagefault_out_of_memory();
+ } else if (fault & VM_FAULT_SIGBUS) {
/* Kernel mode? Handle exceptions or die */
if (!(regs->psw.mask & PSW_MASK_PSTATE))
do_no_context(regs, int_code, trans_exc_code);
@@ -429,10 +432,9 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write)
access = write ? VM_WRITE : VM_READ;
fault = do_exception(&regs, access, uaddr | 2);
if (unlikely(fault)) {
- if (fault & VM_FAULT_OOM) {
- pagefault_out_of_memory();
- fault = 0;
- } else if (fault & VM_FAULT_SIGBUS)
+ if (fault & VM_FAULT_OOM)
+ return -EFAULT;
+ else if (fault & VM_FAULT_SIGBUS)
do_sigbus(&regs, pgm_int_code, uaddr);
}
return fault ? -EFAULT : 0;
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