| Message ID | 20220218094056.2056251-1-luofei@unicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/2] hw/poison: Avoid the impact of hwpoison_filter() return value on mce handler | expand |
Conventionally, "hwpoison" or "HWPOISON" (instead of "hw/poison") is used in the subsystem tag in $SUBJECT, so could you align it (for grep friendliness) ? # I should've mentioned this in previous review round, sorry. On Fri, Feb 18, 2022 at 04:40:56AM -0500, luofei wrote: > 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 value(-EHWPOISON), 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 a new MF_MCE__HANDLE flag is introdulced to identify the ^^ ^^^^^^^^^^^ single '_' ? introduced > call from the mce handler and instruct hwpoison_filter() to > return -EHWPOISON, other return 0 for compatibility with the ^^^^^ otherwise ? > hwpoison injector. > > Signed-off-by: luofei <luofei@unicloud.com> The diff looks ok to me, so with updates on the subject/description ... Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Thanks, Naoya Horiguchi > --- > arch/x86/kernel/cpu/mce/core.c | 15 +++++++++------ > include/linux/mm.h | 1 + > mm/memory-failure.c | 14 ++++++++++++-- > 3 files changed, 22 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c > index 5818b837fd4d..de29165c65b6 100644 > --- a/arch/x86/kernel/cpu/mce/core.c > +++ b/arch/x86/kernel/cpu/mce/core.c > @@ -612,7 +612,7 @@ static int uc_decode_notifier(struct notifier_block *nb, unsigned long val, > return NOTIFY_DONE; > > pfn = mce->addr >> PAGE_SHIFT; > - if (!memory_failure(pfn, 0)) { > + if (!memory_failure(pfn, MF_MCE_HANDLE)) { > set_mce_nospec(pfn, whole_page(mce)); > mce->kflags |= MCE_HANDLED_UC; > } > @@ -1286,7 +1286,7 @@ static void kill_me_now(struct callback_head *ch) > static void kill_me_maybe(struct callback_head *cb) > { > struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); > - int flags = MF_ACTION_REQUIRED; > + int flags = MF_ACTION_REQUIRED | MF_MCE_HANDLE; > int ret; > > p->mce_count = 0; > @@ -1303,9 +1303,12 @@ static void kill_me_maybe(struct callback_head *cb) > } > > /* > - * -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. > + * -EHWPOISON from memory_failure() means that memory_failure() did > + * not handle the error event for the following reason: > + * - SIGBUS has already been sent to the current process with the > + * proper error info, or > + * - hwpoison_filter() filtered the event, > + * so no need to deal with it more. > */ > if (ret == -EHWPOISON) > return; > @@ -1320,7 +1323,7 @@ static void kill_me_never(struct callback_head *cb) > > p->mce_count = 0; > pr_err("Kernel accessed poison in user space at %llx\n", p->mce_addr); > - if (!memory_failure(p->mce_addr >> PAGE_SHIFT, 0)) > + if (!memory_failure(p->mce_addr >> PAGE_SHIFT, MF_MCE_HANDLE)) > set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page); > } > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 213cc569b192..f4703f948e9a 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3188,6 +3188,7 @@ enum mf_flags { > MF_MUST_KILL = 1 << 2, > MF_SOFT_OFFLINE = 1 << 3, > MF_UNPOISON = 1 << 4, > + MF_MCE_HANDLE = 1 << 5, > }; > extern int memory_failure(unsigned long pfn, int flags); > extern void memory_failure_queue(unsigned long pfn, int flags); > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 97a9ed8f87a9..59d6d939a752 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1526,7 +1526,10 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) > if (TestClearPageHWPoison(head)) > num_poisoned_pages_dec(); > unlock_page(head); > - return 0; > + if (flags & MF_MCE_HANDLE) > + return -EHWPOISON; > + else > + return 0; > } > unlock_page(head); > res = MF_FAILED; > @@ -1613,7 +1616,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > goto out; > > if (hwpoison_filter(page)) { > - rc = 0; > + if (flags & MF_MCE_HANDLE) > + rc = -EHWPOISON; > + else > + rc = 0; > goto unlock; > } > > @@ -1837,6 +1843,10 @@ int memory_failure(unsigned long pfn, int flags) > num_poisoned_pages_dec(); > unlock_page(p); > put_page(p); > + if (flags & MF_MCE_HANDLE) > + res = -EHWPOISON; > + else > + res = 0; > goto unlock_mutex; > } > > -- > 2.27.0
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 5818b837fd4d..de29165c65b6 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -612,7 +612,7 @@ static int uc_decode_notifier(struct notifier_block *nb, unsigned long val, return NOTIFY_DONE; pfn = mce->addr >> PAGE_SHIFT; - if (!memory_failure(pfn, 0)) { + if (!memory_failure(pfn, MF_MCE_HANDLE)) { set_mce_nospec(pfn, whole_page(mce)); mce->kflags |= MCE_HANDLED_UC; } @@ -1286,7 +1286,7 @@ static void kill_me_now(struct callback_head *ch) static void kill_me_maybe(struct callback_head *cb) { struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); - int flags = MF_ACTION_REQUIRED; + int flags = MF_ACTION_REQUIRED | MF_MCE_HANDLE; int ret; p->mce_count = 0; @@ -1303,9 +1303,12 @@ static void kill_me_maybe(struct callback_head *cb) } /* - * -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. + * -EHWPOISON from memory_failure() means that memory_failure() did + * not handle the error event for the following reason: + * - SIGBUS has already been sent to the current process with the + * proper error info, or + * - hwpoison_filter() filtered the event, + * so no need to deal with it more. */ if (ret == -EHWPOISON) return; @@ -1320,7 +1323,7 @@ static void kill_me_never(struct callback_head *cb) p->mce_count = 0; pr_err("Kernel accessed poison in user space at %llx\n", p->mce_addr); - if (!memory_failure(p->mce_addr >> PAGE_SHIFT, 0)) + if (!memory_failure(p->mce_addr >> PAGE_SHIFT, MF_MCE_HANDLE)) set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page); } diff --git a/include/linux/mm.h b/include/linux/mm.h index 213cc569b192..f4703f948e9a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3188,6 +3188,7 @@ enum mf_flags { MF_MUST_KILL = 1 << 2, MF_SOFT_OFFLINE = 1 << 3, MF_UNPOISON = 1 << 4, + MF_MCE_HANDLE = 1 << 5, }; extern int memory_failure(unsigned long pfn, int flags); extern void memory_failure_queue(unsigned long pfn, int flags); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 97a9ed8f87a9..59d6d939a752 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1526,7 +1526,10 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) if (TestClearPageHWPoison(head)) num_poisoned_pages_dec(); unlock_page(head); - return 0; + if (flags & MF_MCE_HANDLE) + return -EHWPOISON; + else + return 0; } unlock_page(head); res = MF_FAILED; @@ -1613,7 +1616,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, goto out; if (hwpoison_filter(page)) { - rc = 0; + if (flags & MF_MCE_HANDLE) + rc = -EHWPOISON; + else + rc = 0; goto unlock; } @@ -1837,6 +1843,10 @@ int memory_failure(unsigned long pfn, int flags) num_poisoned_pages_dec(); unlock_page(p); put_page(p); + if (flags & MF_MCE_HANDLE) + res = -EHWPOISON; + else + res = 0; goto unlock_mutex; }
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 value(-EHWPOISON), 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 a new MF_MCE__HANDLE flag is introdulced to identify the call from the mce handler and instruct hwpoison_filter() to return -EHWPOISON, other return 0 for compatibility with the hwpoison injector. Signed-off-by: luofei <luofei@unicloud.com> --- arch/x86/kernel/cpu/mce/core.c | 15 +++++++++------ include/linux/mm.h | 1 + mm/memory-failure.c | 14 ++++++++++++-- 3 files changed, 22 insertions(+), 8 deletions(-)