Both EX_TYPE_FAULT_MCE_SAFE and EX_TYPE_DEFAULT_MCE_SAFE exception
fixup types are used to identify fixups which allow in kernel #MC
recovery, that is the Machine Check Safe Copy.
For now, the MCE_IN_KERNEL_COPYIN flag is only set for EX_TYPE_COPY
and EX_TYPE_UACCESS when copy from user, and corrupted page is
isolated in this case, for MC-safe copy, memory_failure() is not
always called, some places, like __wp_page_copy_user, copy_subpage,
copy_user_gigantic_page and ksm_might_need_to_copy manually call
memory_failure_queue() to cope with such unhandled error pages,
recently coredump hwposion recovery support[1] is asked to do the
same thing, and there are some other already existed MC-safe copy
scenarios, eg, nvdimm, dm-writecache, dax, which has similar issue.
The best way to fix them is set MCE_IN_KERNEL_COPYIN to MCE_SAFE
exception, then kill_me_never() will be queued to call memory_failure()
in do_machine_check() to isolate corrupted page, which avoid calling
memory_failure_queue() after every MC-safe copy return.
[1] https://lkml.kernel.org/r/20230417045323.11054-1-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
arch/x86/kernel/cpu/mce/severity.c | 3 +--
mm/ksm.c | 1 -
mm/memory.c | 12 +++---------
3 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index c4477162c07d..63e94484c5d6 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -293,12 +293,11 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
case EX_TYPE_COPY:
if (!copy_user)
return IN_KERNEL;
- m->kflags |= MCE_IN_KERNEL_COPYIN;
fallthrough;
case EX_TYPE_FAULT_MCE_SAFE:
case EX_TYPE_DEFAULT_MCE_SAFE:
- m->kflags |= MCE_IN_KERNEL_RECOV;
+ m->kflags |= MCE_IN_KERNEL_RECOV | MCE_IN_KERNEL_COPYIN;
return IN_KERNEL_RECOV;
default:
diff --git a/mm/ksm.c b/mm/ksm.c
index 0156bded3a66..7abdf4892387 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2794,7 +2794,6 @@ struct page *ksm_might_need_to_copy(struct page *page,
if (new_page) {
if (copy_mc_user_highpage(new_page, page, address, vma)) {
put_page(new_page);
- memory_failure_queue(page_to_pfn(page), 0);
return ERR_PTR(-EHWPOISON);
}
SetPageDirty(new_page);
diff --git a/mm/memory.c b/mm/memory.c
index 5e2c6b1fc00e..c0f586257017 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2814,10 +2814,8 @@ static inline int __wp_page_copy_user(struct page *dst, struct page *src,
unsigned long addr = vmf->address;
if (likely(src)) {
- if (copy_mc_user_highpage(dst, src, addr, vma)) {
- memory_failure_queue(page_to_pfn(src), 0);
+ if (copy_mc_user_highpage(dst, src, addr, vma))
return -EHWPOISON;
- }
return 0;
}
@@ -5852,10 +5850,8 @@ static int copy_user_gigantic_page(struct folio *dst, struct folio *src,
cond_resched();
if (copy_mc_user_highpage(dst_page, src_page,
- addr + i*PAGE_SIZE, vma)) {
- memory_failure_queue(page_to_pfn(src_page), 0);
+ addr + i*PAGE_SIZE, vma))
return -EHWPOISON;
- }
}
return 0;
}
@@ -5871,10 +5867,8 @@ static int copy_subpage(unsigned long addr, int idx, void *arg)
struct copy_subpage_arg *copy_arg = arg;
if (copy_mc_user_highpage(copy_arg->dst + idx, copy_arg->src + idx,
- addr, copy_arg->vma)) {
- memory_failure_queue(page_to_pfn(copy_arg->src + idx), 0);
+ addr, copy_arg->vma))
return -EHWPOISON;
- }
return 0;
}
