This patch backporting to v6.6.43+ cherry picked from
commit df39038cd895 ("s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()")
There is no support for HWPOISON, MEMORY_FAILURE, or ARCH_HAS_COPY_MC on
s390. Therefore we do not expect to see VM_FAULT_HWPOISON in
do_fault_error().
However, since commit af19487f00f3 ("mm: make PTE_MARKER_SWAPIN_ERROR more
general"), it is possible to see VM_FAULT_HWPOISON in combination with
PTE_MARKER_POISONED, even on architectures that do not support HWPOISON
otherwise. In this case, we will end up on the BUG() in do_fault_error().
Fix this by treating VM_FAULT_HWPOISON the same as VM_FAULT_SIGBUS, similar
to x86 when MEMORY_FAILURE is not configured. Also print unexpected fault
flags, for easier debugging.
Note that VM_FAULT_HWPOISON_LARGE is not expected, because s390 cannot
support swap entries on other levels than PTE level.
Cc: stable@xxxxxxxxxxxxxxx # 6.6+
Fixes: af19487f00f3 ("mm: make PTE_MARKER_SWAPIN_ERROR more general")
Reported-by: Yunseong Kim <yskelg@xxxxxxxxx>
Tested-by: Yunseong Kim <yskelg@xxxxxxxxx>
Acked-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Signed-off-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
Message-ID: <20240715180416.3632453-1-gerald.schaefer@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Yunseong Kim <yskelg@xxxxxxxxx>
---
arch/s390/mm/fault.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index b678295931c3..1a231181a413 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -331,14 +331,16 @@ static noinline void do_fault_error(struct pt_regs *regs, vm_fault_t fault)
do_no_context(regs, fault);
else
do_sigsegv(regs, SEGV_MAPERR);
- } else if (fault & VM_FAULT_SIGBUS) {
+ } else if (fault & (VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)) {
/* Kernel mode? Handle exceptions or die */
if (!user_mode(regs))
do_no_context(regs, fault);
else
do_sigbus(regs);
- } else
+ } else {
+ pr_emerg("Unexpected fault flags: %08x\n", fault);
BUG();
+ }
break;
}
}
--
2.45.2
