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b=igPHqvj7zjO+KjJ4eQCQp01kcNJMiKpK8P60ECpGWjlcwNemAasI4MegJNtFLVojJSQSeME9P/DtpQn0vDnbGUGIPklvQaTOXFwK0YAOuP4fRO3xksCgx2NGTfzZpGU7bhbEenXjb49yMYNb/bvl7oIk1Mmuiu8jzRZwrk/51XM= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R301e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=32;SR=0;TI=SMTPD_---0W1SD-3m_1709190322; Received: from 30.240.112.180(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0W1SD-3m_1709190322) by smtp.aliyun-inc.com; Thu, 29 Feb 2024 15:05:24 +0800 Message-ID: Date: Thu, 29 Feb 2024 15:05:19 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v11 3/3] ACPI: APEI: handle synchronous exceptions in task work to send correct SIGBUS si_code Content-Language: en-US To: "Luck, Tony" , "james.morse@arm.com" , "bp@alien8.de" 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, mingo@redhat.com, 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, bp@alien8.de, rafael@kernel.org, wangkefeng.wang@huawei.com, tanxiaofei@huawei.com, mawupeng1@huawei.com, linmiaohe@huawei.com, naoya.horiguchi@nec.com, gregkh@linuxfoundation.org, will@kernel.org, jarkko@kernel.org References: <20221027042445.60108-1-xueshuai@linux.alibaba.com> <20240204080144.7977-4-xueshuai@linux.alibaba.com> From: Shuai Xue In-Reply-To: <20240204080144.7977-4-xueshuai@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EDE79140010 X-Stat-Signature: pmk6yfc8x7ydunnz7mjejff7ii9fjm3g X-HE-Tag: 1709190328-437926 X-HE-Meta: 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 VOLr1OI2 LvVNBAGzogf5l8q4fdTuGhbn+iv+ygJnLLtHP 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: On 2024/2/4 16:01, Shuai Xue wrote: > Hardware errors could be signaled by asynchronous interrupt, e.g. when an > error is detected by a background scrubber, or signaled by synchronous > exception, e.g. when a CPU tries to access a poisoned cache line. 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 should > terminate the current process which accessing the 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, the memory failure recovery is incorrectly sending a SIGBUS > with wrong error code BUS_MCEERR_AO for synchronous errors in early kill > mode, even MF_ACTION_REQUIRED is set. The main problem is that > synchronous errors are queued as a memory_failure() work, and are > executed within a kernel thread context, not the user-space process that > encountered the corrupted memory on ARM64 platform. As a result, when > kill_proc() is called to terminate the process, it sends the incorrect > SIGBUS error code because the context in which it operates is not the > one where the error was triggered. > > To this end, queue memory_failure() as a task_work so that it runs in > the context of the process that is actually consuming the poisoned data, > and it will send SIBBUS with si_code BUS_MCEERR_AR. > > Signed-off-by: Shuai Xue > Tested-by: Ma Wupeng > Reviewed-by: Kefeng Wang > Reviewed-by: Xiaofei Tan > Reviewed-by: Baolin Wang > --- > drivers/acpi/apei/ghes.c | 77 +++++++++++++++++++++++----------------- > include/acpi/ghes.h | 3 -- > mm/memory-failure.c | 13 ------- > 3 files changed, 44 insertions(+), 49 deletions(-) > > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c > index 0892550732d4..e5086d795bee 100644 > --- a/drivers/acpi/apei/ghes.c > +++ b/drivers/acpi/apei/ghes.c > @@ -465,28 +465,41 @@ 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 sync_task_work - for synchronous RAS event > + * > + * @twork: callback_head for task work > + * @pfn: page frame number of corrupted page > + * @flags: fine tune action taken > + * > + * Structure to pass task work to be handled before > + * ret_to_user via task_work_add(). > */ > -static void ghes_kick_task_work(struct callback_head *head) > +struct sync_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; > + int ret; > + struct sync_task_work *twcb = > + container_of(twork, struct sync_task_work, twork); > > - 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("Sending SIGBUS to current task due to memory error not recovered"); > + force_sig(SIGBUS); > } > > static bool ghes_do_memory_failure(u64 physical_addr, int flags) > { > unsigned long pfn; > + struct sync_task_work *twcb; > > if (!IS_ENABLED(CONFIG_ACPI_APEI_MEMORY_FAILURE)) > return false; > @@ -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; > } > @@ -746,7 +771,7 @@ int cxl_cper_unregister_callback(cxl_cper_callback callback) > } > EXPORT_SYMBOL_NS_GPL(cxl_cper_unregister_callback, 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; > @@ -814,8 +839,6 @@ static bool ghes_do_proc(struct ghes *ghes, > pr_err("Sending SIGBUS to current task due to memory error not recovered"); > force_sig(SIGBUS); > } > - > - return queued; > } > > static void __ghes_print_estatus(const char *pfx, > @@ -1117,9 +1140,7 @@ 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); > /* > @@ -1134,25 +1155,16 @@ 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; > } > @@ -1213,7 +1225,6 @@ 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/mm/memory-failure.c b/mm/memory-failure.c > index d33729c48eff..4ad663bdc1d5 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -2462,19 +2462,6 @@ 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; Hi, Tony, Borislav, and James: Any comments to this patch? Looking forward to hear from you. Best Regards, Shuai