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authorJonathan T. Looney <jtl@FreeBSD.org>2026-01-27 02:11:10 +0000
committerJonathan T. Looney <jtl@FreeBSD.org>2026-01-27 20:27:51 +0000
commit37d86e9487754b8541cd4418a4c42999bbb2761f (patch)
tree00c91a0c7293b802a8d9a03796f1719e785b68e7
parent9c151e1fbf1a71a4912afa9693a39d55a00db4eb (diff)
witness: mark relationships defined in order_lists[]
Mark the lock relationships defined in order_lists[] and use that information to print better messages when a LOR violates one of these relationships. Suggested by: markj Reviewed by: kib, markj MFC after: 1 month Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D54903
-rw-r--r--sys/kern/subr_witness.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/sys/kern/subr_witness.c b/sys/kern/subr_witness.c
index a332d6bace2a..7437a7e238f0 100644
--- a/sys/kern/subr_witness.c
+++ b/sys/kern/subr_witness.c
@@ -168,7 +168,7 @@
#define WITNESS_RELATED_MASK (WITNESS_ANCESTOR_MASK | WITNESS_DESCENDANT_MASK)
#define WITNESS_REVERSAL 0x10 /* A lock order reversal has been observed. */
#define WITNESS_RESERVED1 0x20 /* Unused flag, reserved. */
-#define WITNESS_RESERVED2 0x40 /* Unused flag, reserved. */
+#define WITNESS_ORDER_LISTS 0x40 /* Relationship set in order_lists[]. */
#define WITNESS_LOCK_ORDER_KNOWN 0x80 /* This lock order is known. */
/* Descendant to ancestor flags */
@@ -858,6 +858,10 @@ witness_startup(void *mem)
continue;
w1->w_file = "order list";
itismychild(w, w1);
+ w_rmatrix[w->w_index][w1->w_index] |=
+ WITNESS_ORDER_LISTS;
+ w_rmatrix[w1->w_index][w->w_index] |=
+ WITNESS_ORDER_LISTS;
w = w1;
}
}
@@ -1273,6 +1277,7 @@ sbuf_print_verbose_witness_stacks(struct verbose_tracker *t)
{
struct witness_lock_order_data *data;
int i;
+ bool hardcoded;
for (i = 0; i < (2 * t->pair_count); i += 2) {
mtx_lock_spin(&w_mtx);
@@ -1294,18 +1299,20 @@ sbuf_print_verbose_witness_stacks(struct verbose_tracker *t)
data = witness_lock_order_get(&t->t_w1, &t->t_w2);
if (data != NULL)
stack_copy(&data->wlod_stack, &t->t_stack);
+ hardcoded = (w_rmatrix[t->pairs[i]][t->pairs[i + 1]] &
+ WITNESS_ORDER_LISTS) == WITNESS_ORDER_LISTS;
mtx_unlock_spin(&w_mtx);
sbuf_printf(t->sb,
- "Lock order \"%s\"(%s) -> \"%s\"(%s) first seen at:\n",
+ "%slock order \"%s\"(%s) -> \"%s\"(%s) first seen at:\n",
+ hardcoded ? "hardcoded " : "",
t->t_w1.w_name, t->t_w1.w_class->lc_name,
t->t_w2.w_name, t->t_w2.w_class->lc_name);
if (data != NULL)
stack_sbuf_print_flags(t->sb, &t->t_stack,
t->alloc_flags, STACK_SBUF_FMT_LONG);
else
- sbuf_printf(t->sb,
- "(No stack trace--hardcoded relationship?)\n");
+ sbuf_printf(t->sb, "(No stack trace)\n");
sbuf_putc(t->sb, '\n');
}
}