I got a multipath segfault while running iscsi login/logout and following scripts in parallel: #!/bin/bash interval=1 while true do multipath -F &> /dev/null multipath -r &> /dev/null multipath -v2 &> /dev/null multipath -ll &> /dev/null sleep $interval done This is the debuginfo: #0 0x00007f3805e4df58 in add (ctx=0x55d1569e4a00, ud=0x55d1569bafd0) at nvme.c:801 801 if (strcmp("disk", udev_device_get_devtype(ud))) (gdb) bt #0 0x00007f3805e4df58 in add (ctx=0x55d1569e4a00, ud=0x55d1569bafd0) at nvme.c:801 #1 0x00007f3806687a44 in add_foreign (udev=0x55d1569bafd0) at foreign.c:299 #2 0x00007f3806665abf in is_claimed_by_foreign (ud=<optimized out>) at foreign.h:316 #3 pathinfo (pp=0x55d1569e9f50, conf=0x55d1569b92d0, mask=69) at discovery.c:2064 #4 0x000055d154c91cbb in check_usable_paths (conf=0x55d1569b92d0, devpath=0x55d1569e3200 "dm-6", dev_type=<optimized out>) at main.c:368 #5 0x000055d154c910a5 in main (argc=3, argv=<optimized out>) at main.c:1057 In add() at libmultipath/foreign/nvme.c, udev_device_get_devtype(ud) return a NULL pointer then dereferenced. Here, NULL check is needed. Check if udev_device_get_devtype return NULL before dereferencing it. Signed-off-by: lutianxiong <lutianxiong huawei com> Signed-off-by: lixiaokeng <lixiaokeng@xxxxxxxxxx> --- libmultipath/foreign/nvme.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/libmultipath/foreign/nvme.c b/libmultipath/foreign/nvme.c index 280b6bd..6061999 100644 --- a/libmultipath/foreign/nvme.c +++ b/libmultipath/foreign/nvme.c @@ -600,12 +600,14 @@ int add(struct context *ctx, struct udev_device *ud) { struct udev_device *subsys; int rc; + const char *devtype; condlog(5, "%s called for \"%s\"", __func__, THIS); if (ud == NULL) return FOREIGN_ERR; - if (strcmp("disk", udev_device_get_devtype(ud))) + if ((devtype = udev_device_get_devtype(ud)) == NULL || + strcmp("disk", devtype)) return FOREIGN_IGNORED; subsys = udev_device_get_parent_with_subsystem_devtype(ud, -- -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel