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From:   Liu Xinpeng <liuxp11@chinatelecom.cn>
To:     keescook@chromium.org, anton@enomsg.org, ccross@android.com,
        tony.luck@intel.com, enb@kernel.org, ames.morse@arm.com,
        bp@alien8.de, linux-kernel@vger.kernel.org,
        linux-acpi@vger.kernel.org
Cc:     Liu Xinpeng <liuxp11@chinatelecom.cn>
Subject: [PATCH] ACPI: APEI: fix missing erst record id
Date:   Tue,  5 Apr 2022 11:25:33 +0800
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record_id is in the erst_record_id_cache but not in storage,so erst_read will
return -ENOENT, and then goto retry_next, erst_get_record_id_next skip a
record_id. This can result in printing the records just in the cache.

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

Signed-off-by: Liu Xinpeng <liuxp11@chinatelecom.cn>
---
 drivers/acpi/apei/erst-dbg.c |  4 +++-
 drivers/acpi/apei/erst.c     | 34 +++++++++++++++++++++++++++++++---
 include/acpi/apei.h          |  1 +
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c
index c740f0faad39..1b94d5e2eaf3 100644
--- a/drivers/acpi/apei/erst-dbg.c
+++ b/drivers/acpi/apei/erst-dbg.c
@@ -113,8 +113,10 @@ static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
 retry:
 	rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
 	/* The record may be cleared by others, try read next record */
-	if (rc == -ENOENT)
+	if (rc == -ENOENT){
+		erst_clear_cache(id);
 		goto retry_next;
+	}
 	if (rc < 0)
 		goto out;
 	if (len > ERST_DBG_RECORD_LEN_MAX) {
diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index 698d67cee052..dcf08e24bab3 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -856,6 +856,31 @@ ssize_t erst_read(u64 record_id, struct cper_record_header *record,
 }
 EXPORT_SYMBOL_GPL(erst_read);
 
+int erst_clear_cache(u64 record_id)
+{
+	int rc, i;
+	u64 *entries;
+
+	if (erst_disable)
+		return -ENODEV;
+
+	rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
+	if (rc)
+		return rc;
+
+	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);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(erst_clear_cache);
+
 int erst_clear(u64 record_id)
 {
 	int rc, i;
@@ -998,14 +1023,17 @@ static ssize_t erst_reader(struct pstore_record *record)
 
 	len = erst_read(record_id, &rcd->hdr, rcd_len);
 	/* The record may be cleared by others, try read next record */
-	if (len == -ENOENT)
+	if (len == -ENOENT){
+		erst_clear_cache(record_id);
 		goto skip;
-	else if (len < 0 || len < sizeof(*rcd)) {
+	} else if (len < 0 || len < sizeof(*rcd)) {
 		rc = -EIO;
 		goto out;
 	}
-	if (!guid_equal(&rcd->hdr.creator_id, &CPER_CREATOR_PSTORE))
+	if (!guid_equal(&rcd->hdr.creator_id, &CPER_CREATOR_PSTORE)){
+		erst_clear_cache(record_id);
 		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..f8c11ff4115a 100644
--- a/include/acpi/apei.h
+++ b/include/acpi/apei.h
@@ -47,6 +47,7 @@ void erst_get_record_id_end(void);
 ssize_t erst_read(u64 record_id, struct cper_record_header *record,
 		  size_t buflen);
 int erst_clear(u64 record_id);
+int erst_clear_cache(u64 record_id);
 
 int arch_apei_enable_cmcff(struct acpi_hest_header *hest_hdr, void *data);
 void arch_apei_report_mem_error(int sev, struct cper_sec_mem_err *mem_err);
-- 
2.23.0