diff mbox series

[rasdaemon,1/2] ras-page-isolation: fix do_page_offline always considers page offline is successful

Message ID 1604138235-7142-2-git-send-email-lvying6@huawei.com (mailing list archive)
State New, archived
Headers show
Series ras-page-isolation bugfix | expand

Commit Message

Lv Ying Oct. 31, 2020, 9:57 a.m. UTC 
From: lvying <lvying6@huawei.com>

do_page_offline always consider page offline is successful even if kernel
soft/hard offline page failed

when I set /etc/sysconfig/rasdaemon PAGE_CE_THRESHOLD="1" i.e when a
page's address occurs Corrected Error, rasdaemon will trigger this page
soft offline. Also I put a livepatch into kernel's
store_soft_offline_page to observe this function's return vlaue.

When I inject a CE into address 0x3f7ec30000
kernel log:
soft_offline: 0x3f7ec30: unknown non LRU page type ffffe0000000000 ()
[store_soft_offline_page]return from soft_offline_page: -5

rasdaemon log:
rasdaemon[73711]: cpu 00:rasdaemon: Corrected Errors at 0x3f7ec30000 exceed threshold
rasdaemon[73711]: rasdaemon: Result of offlining page at 0x3f7ec30000: offlined

At the same time, I use strace to record rasdaemon's system call:
strace -p 73711
openat(AT_FDCWD, "/sys/devices/system/memory/soft_offline_page",
	O_WRONLY|O_CREAT|O_TRUNC, 0666) = 28
fstat(28, {st_mode=S_IFREG|0200, st_size=4096, ...}) = 0
write(28, "0x3f7ec30000", 12)           = -1 EIO (Input/output error)
close(28)                               = 0

So, kernel actually soft offline pfn 0x3f7ec30 failed, store_soft_offline_page
return -EIO. However, rasdaemon always considers the page offline is
successful.
According to strace display, ferror is unaware of the failure of the
write syscall. So I change fopen-fprintf-ferror-fclose process to
open-write-close process which can be aware of the failure of the write
syscall.

Signed-off-by: lvying <lvying6@huawei.com>
---
 ras-page-isolation.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/ras-page-isolation.c b/ras-page-isolation.c
index 50e4406..dc07545 100644
--- a/ras-page-isolation.c
+++ b/ras-page-isolation.c
@@ -17,6 +17,9 @@ 
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
 #include "ras-logger.h"
 #include "ras-page-isolation.h"
 
@@ -210,18 +213,22 @@  void ras_page_account_init(void)
 
 static int do_page_offline(unsigned long long addr, enum otype type)
 {
-	FILE *offline_file;
-	int err;
+	int fd, rc;
+	char buf[20];
 
-	offline_file = fopen(kernel_offline[type], "w");
-	if (!offline_file)
+	fd = open(kernel_offline[type], O_WRONLY);
+	if (fd == -1) {
+		log(TERM, LOG_ERR, "[%s]:open file: %s failed\n", __func__, kernel_offline[type]);
 		return -1;
+	}
 
-	fprintf(offline_file, "%#llx", addr);
-	err = ferror(offline_file) ? -1 : 0;
-	fclose(offline_file);
-
-	return err;
+	sprintf(buf, "%#llx", addr);
+	rc = write(fd, buf, strlen(buf));
+	if (rc < 0) {
+		log(TERM, LOG_ERR, "page offline addr(%s) by %s failed, errno:%d\n", buf, kernel_offline[type], errno);
+	}
+	close(fd);
+	return rc;
 }
 
 static void page_offline(struct page_record *pr)