commit e4d27840e173491ab29c2d97017da9344e2c2526

Author: lvying <lvying6@huawei.com>

Date:   Sat Oct 31 17:57:14 2020 +0800

    ras-page-isolation: do_page_offline always considers page offline was successful

    do_page_offline always consider page offline was successful even if

    kernel soft/hard offline page failed.

    Calling rasdaemon with:

    	/etc/sysconfig/rasdaemon PAGE_CE_THRESHOLD="1"

    i.e when a page's address occurs Corrected Error, rasdaemon should

    trigger this page soft offline.

    However, after adding a livepatch into kernel's

    store_soft_offline_page to observe this function's return value,

    when injecting a CE into address 0x3f7ec30000, the Kernel

    lot reports:

    	soft_offline: 0x3f7ec30: unknown non LRU page type ffffe0000000000 ()

    	[store_soft_offline_page]return from soft_offline_page: -5

    While rasdaemon log reports:

    	rasdaemon[73711]: cpu 00:rasdaemon: Corrected Errors at 0x3f7ec30000 exceed threshold

    	rasdaemon[73711]: rasdaemon: Result of offlining page at 0x3f7ec30000: offlined

    using strace to record rasdaemon's system call, it reports:

    	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 and

    store_soft_offline_page returned -EIO. However, rasdaemon always

    considers the page offline to be successful.

    According to strace display, ferror was unable of detecting the

    failure of the write syscall.

    This patch changes fopen-fprintf-ferror-fclose process to use

    the lower I/O level, by using instead open-write-close, which

    can detect such syscall failure.

    Signed-off-by: lvying <lvying6@huawei.com>

    Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

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)