The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x df39038cd89525d465c2c8827eb64116873f141a # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024072535-synergy-struggle-8ecc@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
df39038cd895 ("s390/mm: Fix VM_FAULT_HWPOISON handling in do_exception()") b20c8216c1e0 ("s390/mm,fault: move VM_FAULT_ERROR handling to do_exception()") 7c194d84a9ce ("s390/mm,fault: remove VM_FAULT_BADMAP and VM_FAULT_BADACCESS") b61a0922b6dc ("s390/mm,fault: remove VM_FAULT_SIGNAL") 0f86ac4ba713 ("s390/mm,fault: remove VM_FAULT_BADCONTEXT") 0f1a14e0348e ("s390/mm,fault: simplify kfence fault handling") 64ea33fb09f8 ("s390/mm,fault: call do_fault_error() only from do_exception()") 5db06565cad6 ("s390/mm,fault: get rid of do_low_address()") cca12b427d43 ("s390/mm,fault: remove VM_FAULT_PFAULT") 5be05c35e72f ("s390/mm,fault: improve readability by using teid union") 4416d2ed8166 ("s390/mm,fault: use static key for store indication") 9641613f48bb ("s390/mm,fault: use get_fault_address() everywhere") 5c845de331d9 ("s390/mm,fault: remove noinline attribute from all functions") 8dbc33dc8163 ("s390/mm,fault: have balanced braces, remove unnecessary blanks") 7c915a84e5e2 ("s390/mm,fault: reverse x-mas tree coding style") 3aad8c044297 ("s390/mm,fault: remove and improve comments, adjust whitespace")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From df39038cd89525d465c2c8827eb64116873f141a Mon Sep 17 00:00:00 2001 From: Gerald Schaefer gerald.schaefer@linux.ibm.com 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 yskelg@gmail.com Tested-by: Yunseong Kim yskelg@gmail.com Acked-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Gerald Schaefer gerald.schaefer@linux.ibm.com Message-ID: 20240715180416.3632453-1-gerald.schaefer@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 6b19a33c49c2..8e149ef5e89b 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(); } }