[Skiboot] [PATCH] opal-prd: Do not error out on first failure for soft/hard offline.

Mahesh J Salgaonkar mahesh at linux.vnet.ibm.com
Fri May 11 23:58:43 AEST 2018

From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

The memory errors (CEs and UEs) that are detected as part of background
memory scrubbing are reported by PRD asynchronously to opal-prd along with
affected memory ranges. hservice_memory_error() converts these ranges into
page granularity before hooking up them to soft/hard offline-ing

But the current implementation of hservice_memory_error() does not hookup
all the pages to soft/hard offline-ing if any of the page offline action
fails. e.g hard offline can fail for:
      - Pages that are not part of buddy managed pool.
      - Pages that are reserved by kernel using memblock_reserved()
      - Pages that are in use by kernel.

But for the pages that are in use by user space application, the hard
offline marks the page as hwpoison, sends SIGBUS signal to kill the
affected application as recovery action and returns success.

Hence, It is possible that some of the pages in that memory range are in
use by application or free. By stopping on first error we loose the
opportunity to hwpoison the subsequent pages which may be free or in use by
application. This patch fixes this issue.

Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
 external/opal-prd/opal-prd.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/external/opal-prd/opal-prd.c b/external/opal-prd/opal-prd.c
index bc092d186..e3b4439c6 100644
--- a/external/opal-prd/opal-prd.c
+++ b/external/opal-prd/opal-prd.c
@@ -701,7 +701,7 @@ int hservice_memory_error(uint64_t i_start_addr, uint64_t i_endAddr,
 	const char *sysfsfile, *typestr;
 	char buf[ADDR_STRING_SZ];
-	int memfd, rc, n;
+	int memfd, rc, n, ret = 0;
 	uint64_t addr;
 	switch(i_errorType) {
@@ -737,11 +737,11 @@ int hservice_memory_error(uint64_t i_start_addr, uint64_t i_endAddr,
 			pr_log(LOG_CRIT, "MEM: Failed to offline memory! "
 					"page addr: %016lx type: %d: %m",
 				addr, i_errorType);
-			return rc;
+			ret = rc;
-	return 0;
+	return ret;
 uint64_t hservice_get_interface_capabilities(uint64_t set)

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