Depending on the operation requested futex(2) might return the number of
woken threads or an error. That means the following...
mpv CALL futex(0xa58935899b0,0x82<FUTEX_WAKE|FUTEX_PRIVATE_FLAG>,1,0,0)
mpv RET futex -1 errno 1 Operation not permitted
...is not an error but it indicates that 1 thread has been awoken.
Diff below would have saved me quite some time looking in the wrong
direction.
ok?
Index: kdump.c
===================================================================
RCS file: /cvs/src/usr.bin/kdump/kdump.c,v
retrieving revision 1.141
diff -u -p -r1.141 kdump.c
--- kdump.c 18 Jan 2020 23:56:31 -0000 1.141
+++ kdump.c 3 Apr 2020 17:27:36 -0000
@@ -1147,7 +1147,9 @@ doerr:
(void)printf("RESTART");
else if (error == EJUSTRETURN)
(void)printf("JUSTRETURN");
- else {
+ else if (code == SYS_futex) {
+ (void)printf("%d", error);
+ } else {
(void)printf("-1 errno %d", error);
if (fancy)
(void)printf(" %s", strerror(error));
