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charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 0D97440009 X-Stat-Signature: 9nf8iy84brnc9rkikdx68ddo8n6weya9 X-Rspam-User: X-HE-Tag: 1681350600-53195 X-HE-Meta: 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 viXEajb0 hZCZuv9Gsf4V6xzrjZ5otpHWVF0RlNQc/Xmq41AX4TihxejiamZHdkIqhFXtDIHrxS6A1VYauc0+w+Me0sdg5dt4chKEePkKu5f3dQvCakgswQw75EAbzL1hgryuq3cK/KoD873efiyOQXkd7y7I/yHq7fw== 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: On 2023/4/12 PM12:05, Xiaofei Tan wrote: > > 在 2023/4/11 18:48, Shuai Xue 写道: >> Hardware errors could be signaled by synchronous interrupt, e.g.  when an >> error is detected by a background scrubber, or signaled by synchronous >> exception, e.g. when an uncorrected error is consumed. Both synchronous and >> asynchronous error are queued and handled by a dedicated kthread in >> workqueue. >> >> commit 7f17b4a121d0 ("ACPI: APEI: Kick the memory_failure() queue for >> synchronous errors") keep track of whether memory_failure() work was >> queued, and make task_work pending to flush out the workqueue so that the >> work for synchronous error is processed before returning to user-space. >> The trick ensures that the corrupted page is unmapped and poisoned. And >> after returning to user-space, the task starts at current instruction which >> triggering a page fault in which kernel will send SIGBUS to current process >> due to VM_FAULT_HWPOISON. >> >> However, the memory failure recovery for hwpoison-aware mechanisms does not >> work as expected. For example, hwpoison-aware user-space processes like >> QEMU register their customized SIGBUS handler and enable early kill mode by >> seting PF_MCE_EARLY at initialization. Then the kernel will directy notify >> the process by sending a SIGBUS signal in memory failure with wrong >> si_code: the actual user-space process accessing the corrupt memory >> location, but its memory failure work is handled in a kthread context, so >> it will send SIGBUS with BUS_MCEERR_AO si_code to the actual user-space >> process instead of BUS_MCEERR_AR in kill_proc(). >> >> To this end, separate synchronous and asynchronous error handling into >> different paths like X86 platform does: >> >> - valid synchronous errors: queue a task_work to synchronously send SIGBUS >>    before ret_to_user. >> - valid asynchronous errors: queue a work into workqueue to asynchronously >>    handle memory failure. >> - abnormal branches such as invalid PA, unexpected severity, no memory >>    failure config support, invalid GUID section, OOM, etc. >> >> Then for valid synchronous errors, the current context in memory failure is >> exactly belongs to the task consuming poison data and it will send SIBBUS >> with proper si_code. >> >> Fixes: 7f17b4a121d0 ("ACPI: APEI: Kick the memory_failure() queue for synchronous errors") >> Signed-off-by: Shuai Xue >> Tested-by: Ma Wupeng >> --- >>   drivers/acpi/apei/ghes.c | 91 +++++++++++++++++++++++++++------------- >>   include/acpi/ghes.h      |  3 -- >>   mm/memory-failure.c      | 13 ------ >>   3 files changed, 61 insertions(+), 46 deletions(-) >> >> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c >> index c479b85899f5..4b70955e25f9 100644 >> --- a/drivers/acpi/apei/ghes.c >> +++ b/drivers/acpi/apei/ghes.c >> @@ -452,28 +452,51 @@ 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); >> +    kfree(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) >> +        return; >> + >> +    /* >> +     * -EHWPOISON from memory_failure() means that it already sent SIGBUS >> +     * to the current process with the proper error info, >> +     * -EOPNOTSUPP means hwpoison_filter() filtered the error event, >> +     * >> +     * In both cases, no further processing is required. >> +     */ >> +    if (ret == -EHWPOISON || ret == -EOPNOTSUPP) >> +        return; >> + >> +    pr_err("Memory error not recovered"); > > The print could add the following SIGBUS signal sending. > Such as "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; >> @@ -486,6 +509,18 @@ static bool ghes_do_memory_failure(u64 physical_addr, int flags) >>           return false; >>       } >>   +    if (flags == MF_ACTION_REQUIRED && current->mm) { >> +        twcb = kmalloc(sizeof(*twcb), GFP_ATOMIC); >> +        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; >>   } >> @@ -1000,9 +1035,8 @@ 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; >> +    bool queued, sync; >>       u32 len, node_len; >> -    int ret; >>         llnode = llist_del_all(&ghes_estatus_llist); >>       /* >> @@ -1015,27 +1049,25 @@ static void ghes_proc_in_irq(struct irq_work *irq_work) >>           estatus_node = llist_entry(llnode, struct ghes_estatus_node, >>                          llnode); >>           estatus = GHES_ESTATUS_FROM_NODE(estatus_node); >> +        sync = is_hest_sync_notify(estatus_node->ghes); >>           len = cper_estatus_len(estatus); >>           node_len = GHES_ESTATUS_NODE_LEN(len); >> -        task_work_pending = ghes_do_proc(estatus_node->ghes, estatus); >> + >> +        queued = ghes_do_proc(estatus_node->ghes, estatus); >> +        /* >> +         * If no memory failure work is queued for abnormal synchronous >> +         * errors, do a force kill. >> +         */ >> +        if (sync && !queued) >> +            force_sig(SIGBUS); > > Could also add one similar print here as above > Apart from this, > Reviewed-by: Xiaofei Tan Thanks :) Sorry, I missed your replies, because Thunderbird marks an email as Junk, just move it to the Junk folder. I'd like to add above warning message and pick up your reviewed-by tag. Cheers, Shuai > >> + >>           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; >>       } >> @@ -1096,7 +1128,6 @@ 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 3c8bba9f1114..e5e0c308d27f 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 fae9baf3be16..6ea8c325acb3 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -2355,19 +2355,6 @@ 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;