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npf(9): Drop table lock around copyout. 

It is forbidden to hold a spin lock around copyout, and t_lock is a
spin lock.

We need t_lock in order to iterate over the list of entries.
However, during copyout itself, we only need to ensure that the
object we're copying out isn't freed by npf_table_remove or
npf_table_gc.

Fortunately, the only caller of npf_table_list, npf_table_remove, and
npf_table_gc is npfctl_table, and it serializes all of them by the
npf config lock.  So we can safely drop t_lock across copyout.

PR kern/57136
PR kern/57181
This commit is contained in:
riastradh 2023-01-23 13:40:04 +00:00
parent f41ff51f42
commit 2f9d5bcd6c
1 changed files with 4 additions and 2 deletions
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6
sys/net/npf/npf_tableset.c
View File

@ -46,7 +46,7 @@
#ifdef _KERNEL
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: npf_tableset.c,v 1.40 2023/01/22 18:45:43 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: npf_tableset.c,v 1.41 2023/01/23 13:40:04 riastradh Exp $");
#include <sys/param.h>
#include <sys/types.h>
@ -766,15 +766,17 @@ table_ent_copyout(const npf_addr_t *addr, const int alen, npf_netmask_t mask,
}
static int
table_generic_list(const npf_table_t *t, void *ubuf, size_t len)
table_generic_list(npf_table_t *t, void *ubuf, size_t len)
{
npf_tblent_t *ent;
size_t off = 0;
int error = 0;
LIST_FOREACH(ent, &t->t_list, te_listent) {
mutex_exit(&t->t_lock);
error = table_ent_copyout(&ent->te_addr,
ent->te_alen, ent->te_preflen, ubuf, len, &off);
mutex_enter(&t->t_lock);
if (error)
break;
}