Always assume SKIP_GONE_DEVS behaviour and kill the flag

...i.e. GET_DEVS == (GET_DEVS|SKIP_GONE_DEVS)

A null pointer dereference in Incremental.c can be triggered by
replugging a disk while the old name is in use.  When mdadm -I is called
on the new disk we fail the call to sysfs_read().  I audited all the
locations that use GET_DEVS and it appears they can tolerate missing a
drive.  So just make SKIP_GONE_DEVS the default behaviour.

Also fix up remaining unchecked usages of the sysfs_read() return value.

Reported-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/mapfile.c b/mapfile.c
index 0f12559..ffe8e16 100644
--- a/mapfile.c
+++ b/mapfile.c
@@ -368,7 +368,7 @@ void RebuildMap(void)
 	}
 
 	for (md = mdstat ; md ; md = md->next) {
-		struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS|SKIP_GONE_DEVS);
+		struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS);
 		struct mdinfo *sd;
 
 		if (!sra)
@@ -486,7 +486,8 @@ void RebuildMap(void)
 		for (md = mdstat ; md ; md = md->next) {
 			struct mdinfo *sra = sysfs_read(-1, md->devnum,
 							GET_VERSION);
-			sysfs_uevent(sra, "change");
+			if (sra)
+				sysfs_uevent(sra, "change");
 			sysfs_free(sra);
 		}
 	map_free(map);