From: luofei <luofei@xxxxxxxxxxxx> Subject: mm/hwpoison: avoid the impact of hwpoison_filter() return value on mce handler When the hwpoison page meets the filter conditions, it should not be regarded as successful memory_failure() processing for mce handler, but should return a distinct value, otherwise mce handler regards the error page has been identified and isolated, which may lead to calling set_mce_nospec() to change page attribute, etc. Here memory_failure() return -EOPNOTSUPP to indicate that the error event is filtered, mce handler should not take any action for this situation and hwpoison injector should treat as correct. Link: https://lkml.kernel.org/r/20220223082135.2769649-1-luofei@xxxxxxxxxxxx Signed-off-by: luofei <luofei@xxxxxxxxxxxx> Acked-by: Borislav Petkov <bp@xxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx> Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/mce/core.c | 8 +++++--- drivers/base/memory.c | 2 ++ mm/hwpoison-inject.c | 3 ++- mm/madvise.c | 2 ++ mm/memory-failure.c | 9 +++++++-- 5 files changed, 18 insertions(+), 6 deletions(-) --- a/arch/x86/kernel/cpu/mce/core.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler +++ a/arch/x86/kernel/cpu/mce/core.c @@ -1304,10 +1304,12 @@ static void kill_me_maybe(struct callbac /* * -EHWPOISON from memory_failure() means that it already sent SIGBUS - * to the current process with the proper error info, so no need to - * send SIGBUS here again. + * to the current process with the proper error info, + * -EOPNOTSUPP means hwpoison_filter() filtered the error event, + * + * In both cases, no further processing is required. */ - if (ret == -EHWPOISON) + if (ret == -EHWPOISON || ret == -EOPNOTSUPP) return; pr_err("Memory error not recovered"); --- a/drivers/base/memory.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler +++ a/drivers/base/memory.c @@ -555,6 +555,8 @@ static ssize_t hard_offline_page_store(s return -EINVAL; pfn >>= PAGE_SHIFT; ret = memory_failure(pfn, 0); + if (ret == -EOPNOTSUPP) + ret = 0; return ret ? ret : count; } --- a/mm/hwpoison-inject.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler +++ a/mm/hwpoison-inject.c @@ -48,7 +48,8 @@ static int hwpoison_inject(void *data, u inject: pr_info("Injecting memory failure at pfn %#lx\n", pfn); - return memory_failure(pfn, 0); + err = memory_failure(pfn, 0); + return (err == -EOPNOTSUPP) ? 0 : err; } static int hwpoison_unpoison(void *data, u64 val) --- a/mm/madvise.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler +++ a/mm/madvise.c @@ -1067,6 +1067,8 @@ static int madvise_inject_error(int beha pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n", pfn, start); ret = memory_failure(pfn, MF_COUNT_INCREASED); + if (ret == -EOPNOTSUPP) + ret = 0; } if (ret) --- a/mm/memory-failure.c~mm-hwpoison-avoid-the-impact-of-hwpoison_filter-return-value-on-mce-handler +++ a/mm/memory-failure.c @@ -1515,7 +1515,7 @@ static int memory_failure_hugetlb(unsign if (TestClearPageHWPoison(head)) num_poisoned_pages_dec(); unlock_page(head); - return 0; + return -EOPNOTSUPP; } unlock_page(head); res = MF_FAILED; @@ -1602,7 +1602,7 @@ static int memory_failure_dev_pagemap(un goto out; if (hwpoison_filter(page)) { - rc = 0; + rc = -EOPNOTSUPP; goto unlock; } @@ -1671,6 +1671,10 @@ static DEFINE_MUTEX(mf_mutex); * * Must run in process context (e.g. a work queue) with interrupts * enabled and no spinlocks hold. + * + * Return: 0 for successfully handled the memory error, + * -EOPNOTSUPP for memory_filter() filtered the error event, + * < 0(except -EOPNOTSUPP) on failure. */ int memory_failure(unsigned long pfn, int flags) { @@ -1836,6 +1840,7 @@ try_again: num_poisoned_pages_dec(); unlock_page(p); put_page(p); + res = -EOPNOTSUPP; goto unlock_mutex; } _
