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b=KC29tSKmkZw/LugUDrg/1EtKfVIzKYLcSmh3yczuHBaFqmrAf2/GtRzrg5vgX2AN4W2QGCR/3WizWfh7PXiG0zoUNHvXU4Lys4NsYEzi8gEH3RGjHGaAlfZOb8Zg/dB+iaZVKmR9kf77J/eATtxvkJyPCxi12xU5aSfZDj0mY70= Received: from 30.246.161.240(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WLghEcF_1734399677 cluster:ay36) by smtp.aliyun-inc.com; Tue, 17 Dec 2024 09:41:19 +0800 Message-ID: <8a8511f3-ace1-4187-8030-55a72573c63d@linux.alibaba.com> Date: Tue, 17 Dec 2024 09:41:17 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v17 3/3] ACPI: APEI: handle synchronous exceptions in task work To: jane.chu@oracle.com, yazen.ghannam@amd.com, mark.rutland@arm.com, catalin.marinas@arm.com, mingo@redhat.com, robin.murphy@arm.com, Jonathan.Cameron@Huawei.com, bp@alien8.de, rafael@kernel.org, linux-arm-kernel@lists.infradead.org, wangkefeng.wang@huawei.com, tanxiaofei@huawei.com, mawupeng1@huawei.com, tony.luck@intel.com, linmiaohe@huawei.com, naoya.horiguchi@nec.com, james.morse@arm.com, tongtiangen@huawei.com, gregkh@linuxfoundation.org, will@kernel.org, jarkko@kernel.org Cc: linux-acpi@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-edac@vger.kernel.org, x86@kernel.org, justin.he@arm.com, ardb@kernel.org, ying.huang@intel.com, ashish.kalra@amd.com, baolin.wang@linux.alibaba.com, tglx@linutronix.de, dave.hansen@linux.intel.com, lenb@kernel.org, hpa@zytor.com, robert.moore@intel.com, lvying6@huawei.com, xiexiuqi@huawei.com, zhuo.song@linux.alibaba.com References: <20241202030527.20586-1-xueshuai@linux.alibaba.com> <20241202030527.20586-4-xueshuai@linux.alibaba.com> From: Shuai Xue In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 8EF51160006 X-Stat-Signature: rub85x41r6gyet47aff4n7nmn5d1k8r4 X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1734399664-856158 X-HE-Meta: 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 0uPdSvLN BoZ7RxdMUoCABx0zHhhntfzRiuZJX7VsTb2n+BvxpU0V9S5RNF+B4XtcWIiCrrF8VbhoZ15kDYkiR/OSijV4uP9ZSGayqzr/aU1DlJsfIV7+CD85JMQ/kSE4FyTB6ZpTgw6/Gtst5csvFkbFNUoP0y+y79hM8lIb0HRTy5aCIZpKOHWmnxLj4IRtPRqREe31htTdzPcXkRlZnBECCTDAg4oUQh4flLcNNDvdGPFAxFSwRg1+nIoVgMQqxabHjTLe316hucUjLTMhrHZkVUvETcE9WFjqzUD3lp2YbsDsldHp/hs00qR55GUhEQ2OmkZSvY+I4wp+N8Oi4PnNiz9IPRMDS6rcmXzCOEMBALTSpCteovO7+SuffOIZMxQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2024/12/17 07:53, jane.chu@oracle.com 写道: > > On 12/1/2024 7:05 PM, Shuai Xue wrote: >> The memory uncorrected error could be signaled by asynchronous interrupt >> (specifically, SPI in arm64 platform), e.g. when an error is detected by >> a background scrubber, or signaled by synchronous exception >> (specifically, data abort exception in arm64 platform), e.g. when a CPU >> tries to access a poisoned cache line. Currently, both synchronous and >> asynchronous error use memory_failure_queue() to schedule >> memory_failure() to exectute in a kworker context. >> >> As a result, when a user-space process is accessing a poisoned data, a >> data abort is taken and the memory_failure() is executed in the kworker >> context, memory_failure(): >> >>    - will send wrong si_code by SIGBUS signal in early_kill mode, and >>    - can not kill the user-space in some cases resulting a synchronous >>      error infinite loop >> >> Issue 1: send wrong si_code in early_kill mode >> >> Since commit a70297d22132 ("ACPI: APEI: set memory failure flags as >> MF_ACTION_REQUIRED on synchronous events")', the flag MF_ACTION_REQUIRED >> could be used to determine whether a synchronous exception occurs on >> ARM64 platform.  When a synchronous exception is detected, the kernel is >> expected to terminate the current process which has accessed poisoned >> page. This is done by sending a SIGBUS signal with an error code >> BUS_MCEERR_AR, indicating an action-required machine check error on >> read. >> >> However, when kill_proc() is called to terminate the processes who have >> the poisoned page mapped, it sends the incorrect SIGBUS error code >> BUS_MCEERR_AO because the context in which it operates is not the one >> where the error was triggered. >> >> To reproduce this problem: >> >>    #sysctl -w vm.memory_failure_early_kill=1 >>    vm.memory_failure_early_kill = 1 >> >>    # STEP2: inject an UCE error and consume it to trigger a synchronous error >>    #einj_mem_uc single >>    0: single   vaddr = 0xffffb0d75400 paddr = 4092d55b400 >>    injecting ... >>    triggering ... >>    signal 7 code 5 addr 0xffffb0d75000 >>    page not present >>    Test passed >> >> The si_code (code 5) from einj_mem_uc indicates that it is BUS_MCEERR_AO >> error and it is not the fact. >> >> After this patch: >> >>    # STEP1: enable early kill mode >>    #sysctl -w vm.memory_failure_early_kill=1 >>    vm.memory_failure_early_kill = 1 >>    # STEP2: inject an UCE error and consume it to trigger a synchronous error >>    #einj_mem_uc single >>    0: single   vaddr = 0xffffb0d75400 paddr = 4092d55b400 >>    injecting ... >>    triggering ... >>    signal 7 code 4 addr 0xffffb0d75000 >>    page not present >>    Test passed >> >> The si_code (code 4) from einj_mem_uc indicates that it is a BUS_MCEERR_AR >> error as we expected. >> >> Issue 2: a synchronous error infinite loop >> >> If a user-space process, e.g. devmem, accesses a poisoned page for which >> the HWPoison flag is set, kill_accessing_process() is called to send >> SIGBUS to current processs with error info. Because the memory_failure() >> is executed in the kworker context, it will just do nothing but return >> EFAULT. So, devmem will access the posioned page and trigger an >> exception again, resulting in a synchronous error infinite loop. Such >> exception loop may cause platform firmware to exceed some threshold and >> reboot when Linux could have recovered from this error. >> >> To reproduce this problem: >> >>    # STEP 1: inject an UCE error, and kernel will set HWPosion flag for related page >>    #einj_mem_uc single >>    0: single   vaddr = 0xffffb0d75400 paddr = 4092d55b400 >>    injecting ... >>    triggering ... >>    signal 7 code 4 addr 0xffffb0d75000 >>    page not present >>    Test passed >> >>    # STEP 2: access the same page and it will trigger a synchronous error infinite loop >>    devmem 0x4092d55b400 >> >> To fix above two issues, queue memory_failure() as a task_work so that >> it runs in the context of the process that is actually consuming the >> poisoned data. >> >> Signed-off-by: Shuai Xue >> Tested-by: Ma Wupeng >> Reviewed-by: Kefeng Wang >> Reviewed-by: Xiaofei Tan >> Reviewed-by: Baolin Wang >> Reviewed-by: Jarkko Sakkinen >> Reviewed-by: Jonathan Cameron >> --- >>   drivers/acpi/apei/ghes.c | 77 +++++++++++++++++++++++----------------- >>   include/acpi/ghes.h      |  3 -- >>   include/linux/mm.h       |  1 - >>   mm/memory-failure.c      | 13 ------- >>   4 files changed, 44 insertions(+), 50 deletions(-) >> >> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c >> index 106486bdfefc..70f2ee3ad1a8 100644 >> --- a/drivers/acpi/apei/ghes.c >> +++ b/drivers/acpi/apei/ghes.c >> @@ -467,28 +467,41 @@ static void ghes_clear_estatus(struct ghes *ghes, >>   } >>   /* >> - * Called as task_work before returning to user-space. >> - * Ensure any queued work has been done before we return to the context that >> - * triggered the notification. >> + * struct ghes_task_work - for synchronous RAS event >> + * >> + * @twork:                callback_head for task work >> + * @pfn:                  page frame number of corrupted page >> + * @flags:                work control flags >> + * >> + * Structure to pass task work to be handled before >> + * returning to user-space via task_work_add(). >>    */ >> -static void ghes_kick_task_work(struct callback_head *head) >> +struct ghes_task_work { >> +    struct callback_head twork; >> +    u64 pfn; >> +    int flags; >> +}; >> + >> +static void memory_failure_cb(struct callback_head *twork) >>   { >> -    struct acpi_hest_generic_status *estatus; >> -    struct ghes_estatus_node *estatus_node; >> -    u32 node_len; >> +    struct ghes_task_work *twcb = container_of(twork, struct ghes_task_work, twork); >> +    int ret; >> -    estatus_node = container_of(head, struct ghes_estatus_node, task_work); >> -    if (IS_ENABLED(CONFIG_ACPI_APEI_MEMORY_FAILURE)) >> -        memory_failure_queue_kick(estatus_node->task_work_cpu); >> +    ret = memory_failure(twcb->pfn, twcb->flags); >> +    gen_pool_free(ghes_estatus_pool, (unsigned long)twcb, sizeof(*twcb)); >> -    estatus = GHES_ESTATUS_FROM_NODE(estatus_node); >> -    node_len = GHES_ESTATUS_NODE_LEN(cper_estatus_len(estatus)); >> -    gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node, node_len); >> +    if (!ret || ret == -EHWPOISON || ret == -EOPNOTSUPP) >> +        return; >> + >> +    pr_err("%#llx: Sending SIGBUS to %s:%d due to hardware memory corruption\n", >> +            twcb->pfn, current->comm, task_pid_nr(current)); >> +    force_sig(SIGBUS); >>   } >>   static bool ghes_do_memory_failure(u64 physical_addr, int flags) >>   { >>       unsigned long pfn; >> +    struct ghes_task_work *twcb; >>       if (!IS_ENABLED(CONFIG_ACPI_APEI_MEMORY_FAILURE)) >>           return false; >> @@ -501,6 +514,18 @@ static bool ghes_do_memory_failure(u64 physical_addr, int flags) >>           return false; >>       } >> +    if (flags == MF_ACTION_REQUIRED && current->mm) { >> +        twcb = (void *)gen_pool_alloc(ghes_estatus_pool, sizeof(*twcb)); >> +        if (!twcb) >> +            return false; >> + >> +        twcb->pfn = pfn; >> +        twcb->flags = flags; >> +        init_task_work(&twcb->twork, memory_failure_cb); >> +        task_work_add(current, &twcb->twork, TWA_RESUME); >> +        return true; >> +    } >> + >>       memory_failure_queue(pfn, flags); >>       return true; >>   } >> @@ -745,7 +770,7 @@ int cxl_cper_kfifo_get(struct cxl_cper_work_data *wd) >>   } >>   EXPORT_SYMBOL_NS_GPL(cxl_cper_kfifo_get, CXL); >> -static bool ghes_do_proc(struct ghes *ghes, >> +static void ghes_do_proc(struct ghes *ghes, >>                const struct acpi_hest_generic_status *estatus) >>   { >>       int sev, sec_sev; >> @@ -811,8 +836,6 @@ static bool ghes_do_proc(struct ghes *ghes, >>               current->comm, task_pid_nr(current)); >>           force_sig(SIGBUS); >>       } >> - >> -    return queued; >>   } >>   static void __ghes_print_estatus(const char *pfx, >> @@ -1114,9 +1137,7 @@ static void ghes_proc_in_irq(struct irq_work *irq_work) >>       struct ghes_estatus_node *estatus_node; >>       struct acpi_hest_generic *generic; >>       struct acpi_hest_generic_status *estatus; >> -    bool task_work_pending; >>       u32 len, node_len; >> -    int ret; >>       llnode = llist_del_all(&ghes_estatus_llist); >>       /* >> @@ -1131,25 +1152,16 @@ static void ghes_proc_in_irq(struct irq_work *irq_work) >>           estatus = GHES_ESTATUS_FROM_NODE(estatus_node); >>           len = cper_estatus_len(estatus); >>           node_len = GHES_ESTATUS_NODE_LEN(len); >> -        task_work_pending = ghes_do_proc(estatus_node->ghes, estatus); >> + >> +        ghes_do_proc(estatus_node->ghes, estatus); >> + >>           if (!ghes_estatus_cached(estatus)) { >>               generic = estatus_node->generic; >>               if (ghes_print_estatus(NULL, generic, estatus)) >>                   ghes_estatus_cache_add(generic, estatus); >>           } >> - >> -        if (task_work_pending && current->mm) { >> -            estatus_node->task_work.func = ghes_kick_task_work; >> -            estatus_node->task_work_cpu = smp_processor_id(); >> -            ret = task_work_add(current, &estatus_node->task_work, >> -                        TWA_RESUME); >> -            if (ret) >> -                estatus_node->task_work.func = NULL; >> -        } >> - >> -        if (!estatus_node->task_work.func) >> -            gen_pool_free(ghes_estatus_pool, >> -                      (unsigned long)estatus_node, node_len); >> +        gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node, >> +                  node_len); >>           llnode = next; >>       } >> @@ -1210,7 +1222,6 @@ static int ghes_in_nmi_queue_one_entry(struct ghes *ghes, >>       estatus_node->ghes = ghes; >>       estatus_node->generic = ghes->generic; >> -    estatus_node->task_work.func = NULL; >>       estatus = GHES_ESTATUS_FROM_NODE(estatus_node); >>       if (__ghes_read_estatus(estatus, buf_paddr, fixmap_idx, len)) { >> diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h >> index be1dd4c1a917..ebd21b05fe6e 100644 >> --- a/include/acpi/ghes.h >> +++ b/include/acpi/ghes.h >> @@ -35,9 +35,6 @@ struct ghes_estatus_node { >>       struct llist_node llnode; >>       struct acpi_hest_generic *generic; >>       struct ghes *ghes; >> - >> -    int task_work_cpu; >> -    struct callback_head task_work; >>   }; >>   struct ghes_estatus_cache { >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index c39c4945946c..aa4246c7c23e 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -3936,7 +3936,6 @@ enum mf_flags { >>   int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, >>                 unsigned long count, int mf_flags); >>   extern int memory_failure(unsigned long pfn, int flags); >> -extern void memory_failure_queue_kick(int cpu); >>   extern int unpoison_memory(unsigned long pfn); >>   extern atomic_long_t num_poisoned_pages __read_mostly; >>   extern int soft_offline_page(unsigned long pfn, int flags); >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >> index 14c316d7d38d..e0adb665d07b 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -2499,19 +2499,6 @@ static void memory_failure_work_func(struct work_struct *work) >>       } >>   } >> -/* >> - * Process memory_failure work queued on the specified CPU. >> - * Used to avoid return-to-userspace racing with the memory_failure workqueue. >> - */ >> -void memory_failure_queue_kick(int cpu) >> -{ >> -    struct memory_failure_cpu *mf_cpu; >> - >> -    mf_cpu = &per_cpu(memory_failure_cpu, cpu); >> -    cancel_work_sync(&mf_cpu->work); >> -    memory_failure_work_func(&mf_cpu->work); >> -} >> - >>   static int __init memory_failure_init(void) >>   { >>       struct memory_failure_cpu *mf_cpu; > > Looks good. > > Reviewed-by: Jane Chu > > -jane > Thanks. Best Regards, Shuai