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Mon, 14 Apr 2025 22:56:39 +0800 Message-ID: Date: Mon, 14 Apr 2025 22:56:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RESEND PATCH v18 2/2] ACPI: APEI: handle synchronous exceptions in task work To: Hanjun Guo , catalin.marinas@arm.com, sudeep.holla@arm.com, lpieralisi@kernel.org, linux-acpi@vger.kernel.org, yazen.ghannam@amd.com, mark.rutland@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-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@linux.alibaba.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: <20250404112050.42040-1-xueshuai@linux.alibaba.com> <20250404112050.42040-3-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: B06832000E X-Rspamd-Server: rspam05 X-Rspam-User: X-Stat-Signature: axqxspfwtsnms6pomyetd3ugx8x6s65u X-HE-Tag: 1744642604-788250 X-HE-Meta: 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 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 2025/4/14 22:48, Hanjun Guo 写道: > On 2025/4/4 19:20, 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 >> Reviewed-by: Jane Chu >> Reviewed-by: Yazen Ghannam >> --- >>   drivers/acpi/apei/ghes.c | 79 +++++++++++++++++++++++----------------- >>   include/acpi/ghes.h      |  3 -- >>   include/linux/mm.h       |  1 - >>   mm/memory-failure.c      | 13 ------- >>   4 files changed, 45 insertions(+), 51 deletions(-) >> >> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c >> index 50e4d924aa8b..87cf4b373ebe 100644 >> --- a/drivers/acpi/apei/ghes.c >> +++ b/drivers/acpi/apei/ghes.c >> @@ -464,28 +464,41 @@ static void ghes_clear_estatus(struct ghes *ghes, >>           ghes_ack_error(ghes->generic_v2); >>   } >> -/* >> - * 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) >>   { >> +    struct ghes_task_work *twcb; >>       unsigned long pfn; >>       if (!IS_ENABLED(CONFIG_ACPI_APEI_MEMORY_FAILURE)) >> @@ -499,6 +512,18 @@ 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; >>   } >> @@ -743,7 +768,7 @@ 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; >> @@ -809,8 +834,6 @@ 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 8483e09aeb2c..327517bf2168 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -3933,7 +3933,6 @@ 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 327e02fdc029..ad07f673608d 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -2494,19 +2494,6 @@ 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 to me, > > Reviewed-by: Hanjun Guo > > Thanks > Hanjun Thanks. Shuai