On Tue, Apr 12, 2022 at 5:05 AM Liu Xinpeng <liuxp11@xxxxxxxxxxxxxxx> wrote:
>
> Read a record is cleared by others, but the deleted record cache entry is
> still created by erst_get_record_id_next. When next enumerate the records,
> get the cached deleted record, then erst_read return -ENOENT and try to
> get next record, loop back to first ID will return 0 in function
> __erst_record_id_cache_add_one and then set record_id as
> APEI_ERST_INVALID_RECORD_ID, finished this time read operation.
> It will result in read the records just in the cache hereafter.
>
> This patch cleared the deleted record cache, fix the issue that
> "./erst-inject -p" shows record counts not equal to "./erst-inject -n".
>
> A reproducer of the problem(retry many times):
>
> [root@localhost erst-inject]# ./erst-inject -c 0xaaaaa00011
> [root@localhost erst-inject]# ./erst-inject -p
> rc: 273
> rcd sig: CPER
> rcd id: 0xaaaaa00012
> rc: 273
> rcd sig: CPER
> rcd id: 0xaaaaa00013
> rc: 273
> rcd sig: CPER
> rcd id: 0xaaaaa00014
> [root@localhost erst-inject]# ./erst-inject -i 0xaaaaa000006
> [root@localhost erst-inject]# ./erst-inject -i 0xaaaaa000007
> [root@localhost erst-inject]# ./erst-inject -i 0xaaaaa000008
> [root@localhost erst-inject]# ./erst-inject -p
> rc: 273
> rcd sig: CPER
> rcd id: 0xaaaaa00012
> rc: 273
> rcd sig: CPER
> rcd id: 0xaaaaa00013
> rc: 273
> rcd sig: CPER
> rcd id: 0xaaaaa00014
> [root@localhost erst-inject]# ./erst-inject -n
> total error record count: 6
>
> Changelog:
> v1->v2 Fix style problems
> v2->v3 Fix apei_read_mce called erst_get_record_id_next and modify
> the commit message.
> v3->v4 Add erst_clear_cache in another retry.
> v4->v5 Implement a new function for looking for a specific record
> type, suggested by Tony Luck.
> v5->v6 In function erst_clear_cache, using mutex_lock insead of
> mutex_lock_interruptible ensure that the cache is cleared.
> If erst_read return value is less than record head length,
> consider it as EIO; other error return to caller; creatorid is
> not wanted, consider it ENOENT and keep the cache for other types.
> v6->v7 Rename erst_read_record arguments "recordhead" to "recordlen".
>
> Signed-off-by: Liu Xinpeng <liuxp11@xxxxxxxxxxxxxxx>
> Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---
> arch/x86/kernel/cpu/mce/apei.c | 8 ++--
> drivers/acpi/apei/erst-dbg.c | 3 +-
> drivers/acpi/apei/erst.c | 77 +++++++++++++++++++++++++++++++---
> include/acpi/apei.h | 2 +
> 4 files changed, 78 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mce/apei.c b/arch/x86/kernel/cpu/mce/apei.c
> index 0e3ae64d3b76..717192915f28 100644
> --- a/arch/x86/kernel/cpu/mce/apei.c
> +++ b/arch/x86/kernel/cpu/mce/apei.c
> @@ -177,16 +177,14 @@ ssize_t apei_read_mce(struct mce *m, u64 *record_id)
> /* no more record */
> if (*record_id == APEI_ERST_INVALID_RECORD_ID)
> goto out;
> - rc = erst_read(*record_id, &rcd.hdr, sizeof(rcd));
> + rc = erst_read_record(*record_id, &rcd.hdr, sizeof(rcd), sizeof(rcd),
> + &CPER_CREATOR_MCE);
> /* someone else has cleared the record, try next one */
> if (rc == -ENOENT)
> goto retry;
> else if (rc < 0)
> goto out;
> - /* try to skip other type records in storage */
> - else if (rc != sizeof(rcd) ||
> - !guid_equal(&rcd.hdr.creator_id, &CPER_CREATOR_MCE))
> - goto retry;
> +
> memcpy(m, &rcd.mce, sizeof(*m));
> rc = sizeof(*m);
> out:
> diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c
> index c740f0faad39..8bc71cdc2270 100644
> --- a/drivers/acpi/apei/erst-dbg.c
> +++ b/drivers/acpi/apei/erst-dbg.c
> @@ -111,7 +111,8 @@ static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
> goto out;
> }
> retry:
> - rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
> + rc = len = erst_read_record(id, erst_dbg_buf, erst_dbg_buf_len,
> + erst_dbg_buf_len, NULL);
> /* The record may be cleared by others, try read next record */
> if (rc == -ENOENT)
> goto retry_next;
> diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
> index 698d67cee052..31b077eedb58 100644
> --- a/drivers/acpi/apei/erst.c
> +++ b/drivers/acpi/apei/erst.c
> @@ -856,6 +856,74 @@ ssize_t erst_read(u64 record_id, struct cper_record_header *record,
> }
> EXPORT_SYMBOL_GPL(erst_read);
>
> +static void erst_clear_cache(u64 record_id)
> +{
> + int i;
> + u64 *entries;
> +
> + mutex_lock(&erst_record_id_cache.lock);
> +
> + entries = erst_record_id_cache.entries;
> + for (i = 0; i < erst_record_id_cache.len; i++) {
> + if (entries[i] == record_id)
> + entries[i] = APEI_ERST_INVALID_RECORD_ID;
> + }
> + __erst_record_id_cache_compact();
> +
> + mutex_unlock(&erst_record_id_cache.lock);
> +}
> +
> +ssize_t erst_read_record(u64 record_id, struct cper_record_header *record,
> + size_t buflen, size_t recordlen, const guid_t *creatorid)
> +{
> + ssize_t len;
> +
> + /*
> + * if creatorid is NULL, read any record for erst-dbg module
> + */
> + if (creatorid == NULL) {
> + len = erst_read(record_id, record, buflen);
> + if (len == -ENOENT)
> + erst_clear_cache(record_id);
> +
> + return len;
> + }
> +
> + len = erst_read(record_id, record, buflen);
> + /*
> + * if erst_read return value is -ENOENT skip to next record_id,
> + * and clear the record_id cache.
> + */
> + if (len == -ENOENT) {
> + erst_clear_cache(record_id);
> + goto out;
> + }
> +
> + if (len < 0)
> + goto out;
> +
> + /*
> + * if erst_read return value is less than record head length,
> + * consider it as -EIO, and clear the record_id cache.
> + */
> + if (len < recordlen) {
> + len = -EIO;
> + erst_clear_cache(record_id);
> + goto out;
> + }
> +
> + /*
> + * if creatorid is not wanted, consider it as not found,
> + * for skipping to next record_id.
> + */
> + if (!guid_equal(&record->creator_id, creatorid))
> + len = -ENOENT;
> +
> +out:
> + return len;
> +}
> +EXPORT_SYMBOL_GPL(erst_read_record);
> +
> int erst_clear(u64 record_id)
> {
> int rc, i;
> @@ -996,16 +1064,13 @@ static ssize_t erst_reader(struct pstore_record *record)
> goto out;
> }
>
> - len = erst_read(record_id, &rcd->hdr, rcd_len);
> + len = erst_read_record(record_id, &rcd->hdr, rcd_len, sizeof(*rcd),
> + &CPER_CREATOR_PSTORE);
> /* The record may be cleared by others, try read next record */
> if (len == -ENOENT)
> goto skip;
> - else if (len < 0 || len < sizeof(*rcd)) {
> - rc = -EIO;
> + else if (len < 0)
> goto out;
> - }
> - if (!guid_equal(&rcd->hdr.creator_id, &CPER_CREATOR_PSTORE))
> - goto skip;
>
> record->buf = kmalloc(len, GFP_KERNEL);
> if (record->buf == NULL) {
> diff --git a/include/acpi/apei.h b/include/acpi/apei.h
> index afaca3a075e8..dc60f7db5524 100644
> --- a/include/acpi/apei.h
> +++ b/include/acpi/apei.h
> @@ -46,6 +46,8 @@ int erst_get_record_id_next(int *pos, u64 *record_id);
> void erst_get_record_id_end(void);
> ssize_t erst_read(u64 record_id, struct cper_record_header *record,
> size_t buflen);
> +ssize_t erst_read_record(u64 record_id, struct cper_record_header *record,
> + size_t buflen, size_t recordlen, const guid_t *creatorid);
> int erst_clear(u64 record_id);
>
> int arch_apei_enable_cmcff(struct acpi_hest_header *hest_hdr, void *data);
> --
Applied as 5.19 material, thanks!
