6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
commit df39038cd89525d465c2c8827eb64116873f141a upstream.
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_exception().
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_exception().
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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/fault.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -432,12 +432,13 @@ error:
handle_fault_error_nolock(regs, 0);
else
do_sigsegv(regs, SEGV_MAPERR);
- } else if (fault & VM_FAULT_SIGBUS) {
+ } else if (fault & (VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)) {
if (!user_mode(regs))
handle_fault_error_nolock(regs, 0);
else
do_sigbus(regs);
} else {
+ pr_emerg("Unexpected fault flags: %08x\n", fault);
BUG();
}
}
