From df39038cd89525d465c2c8827eb64116873f141a Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Mon, 15 Jul 2024 20:04:16 +0200 Subject: [PATCH] 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_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@vger.kernel.org # 6.6+ Fixes: af19487f00f3 ("mm: make PTE_MARKER_SWAPIN_ERROR more general") Reported-by: Yunseong Kim Tested-by: Yunseong Kim Acked-by: Alexander Gordeev Signed-off-by: Gerald Schaefer Message-ID: <20240715180416.3632453-1-gerald.schaefer@linux.ibm.com> Signed-off-by: Vasily Gorbik --- arch/s390/mm/fault.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 6b19a33c49c292..8e149ef5e89ba8 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -433,12 +433,13 @@ static void do_exception(struct pt_regs *regs, int access) 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(); } }