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[S390] mm: handle kernel caused page fault oom situations

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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>
This commit is contained in:
Heiko Carstens 2011-05-26 09:48:29 +02:00
parent b396637841
commit 99583181cb
1 changed files with 9 additions and 7 deletions
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16
arch/s390/mm/fault.c
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@ -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;