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bh=Q1R5nbpoVj8s2ehcuoCBWYhXSfbwrsjFHMsqM9I9f1A=; b=KwoqZpgFew/vhZLA7+bhdxTVDLoTzWJxnmBU1BVZ/HTmNmYISeN1XQtnQE3/2TShxS4m7EYPYeZ0Us2lVToT+8r1stnBSV3mqQFAyv5VXuqTXfGBZS9QlpN8+qB7TS0MxFJ9FzC47L/j2rE0eM9KKb04LORbz98yVvTXYMNxkP4= Received: from localhost.localdomain(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0WH3mwVk_1728895381 cluster:ay36) by smtp.aliyun-inc.com; Mon, 14 Oct 2024 16:43:03 +0800 From: Shuai Xue To: 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, 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, xueshuai@linux.alibaba.com, 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 Subject: [PATCH v14 3/3] ACPI: APEI: handle synchronous exceptions in task work Date: Mon, 14 Oct 2024 16:42:40 +0800 Message-ID: <20241014084240.18614-4-xueshuai@linux.alibaba.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20221027042445.60108-1-xueshuai@linux.alibaba.com> References: <20221027042445.60108-1-xueshuai@linux.alibaba.com> MIME-Version: 1.0 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: A654D16000A X-Stat-Signature: rpg1ebwe5uuqbscjjafj9iejh6wrwr39 X-Rspam-User: X-HE-Tag: 1728895383-396839 X-HE-Meta: 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 ZjAZeHct F8BzTB1ReuNqLfi8vWoC6tscGbTUKEAfewWnIUS33d570ejgq3xQphfFba3x8V3fIvcaSDgtMuYuPPMKHLIsME6PlRbt3D4WZ44/+/5qllBivkAiLSdw+ZzhDqv5uWuJOCb/Ce9pJN51PRVLsfCNcWdfMY/G2JDoY5vt9nJmb86pGYrU5a4YgOluOcLiWqI6SqjzsDBuihC8YDWWFySQ4Cv4iE83+Im/+C2PZd0QY3WEiFC5oxnzyZBuHECtonzyGBw9C 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: 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 excepction 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() exectute in 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: - 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 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 BUS_MCEERR_AR error as we expected. Issue 2: a synchronous error infinite loop If a user-space process, e.g. devmem, a poisoned page which has been set HWPosion flag, kill_accessing_process() is called to send SIGBUS to the current processs with error info. Because the memory_failure() is executed in the kworker contex, it will just do nothing but return EFAULT. So, devmem will access the posioned page and trigger an excepction again, resulting in a synchronous error infinite loop. Such 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: Jonathan Cameron Reviewed-by: Jarkko Sakkinen --- drivers/acpi/apei/ghes.c | 78 +++++++++++++++++++++++----------------- include/acpi/ghes.h | 3 -- include/linux/mm.h | 1 - mm/memory-failure.c | 13 ------- 4 files changed, 45 insertions(+), 50 deletions(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index f2ee28c44d7a..95e9520eb803 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -467,28 +467,42 @@ 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); + unsigned long pfn = twcb->pfn; + 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("%#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n", + 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 +515,18 @@ 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 +771,7 @@ 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; @@ -810,8 +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, @@ -1113,9 +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); /* @@ -1130,25 +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; } @@ -1209,7 +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 ecf63d2b0582..a1286053dd29 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3923,7 +3923,6 @@ 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 1c5098f32d48..c86e10e5c839 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2496,19 +2496,6 @@ 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;