D31484.id93466.diff
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D31484.id93466.diff
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	diff --git a/sys/netpfil/ipfw/ip_fw2.c b/sys/netpfil/ipfw/ip_fw2.c
	--- a/sys/netpfil/ipfw/ip_fw2.c
	+++ b/sys/netpfil/ipfw/ip_fw2.c
	@@ -1242,7 +1242,7 @@
	* whose version is written in f->cached_id
	* (horrible hacks to avoid changing the ABI).
	*/
	- if (num != IP_FW_TARG && f->cached_id == chain->id)
	+ if (num != IP_FW_TARG && atomic_load_32(&f->cached_id) == chain->id)
	f_pos = f->cached_pos;
	else {
	int i = IP_FW_ARG_TABLEARG(chain, num, skipto);
	@@ -1255,8 +1255,13 @@
	f_pos = ipfw_find_rule(chain, i, 0);
	/* update the cache */
	if (num != IP_FW_TARG) {
	- f->cached_id = chain->id;
	- f->cached_pos = f_pos;
	+ /*
	+ * We don't care about thread synchronization there.
	+ * Even if multiple threads update the cache simultaneously,
	+ * we still get the correct cache value.
	+ */
	+ f->cached_pos = f_pos;
	+ atomic_store_32(&f->cached_id, chain->id);
	}
	}

	diff --git a/sys/netpfil/ipfw/ip_fw_private.h b/sys/netpfil/ipfw/ip_fw_private.h
	--- a/sys/netpfil/ipfw/ip_fw_private.h
	+++ b/sys/netpfil/ipfw/ip_fw_private.h
	@@ -275,7 +275,7 @@
	counter_u64_t cntr; /* Pointer to rule counters */
	uint32_t timestamp; /* tv_sec of last match */
	uint32_t id; /* rule id */
	- uint32_t cached_id; /* used by jump_fast */
	+ volatile uint32_t cached_id; /* used by jump_fast */
	uint32_t cached_pos; /* used by jump_fast */
	uint32_t refcnt; /* number of references */