Date: Mon, 8 Oct 2018 17:36:30 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Matthew Macy <mmacy@nextbsd.org>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Deadlock in VLAN 12-current w/patch Message-ID: <5c130405-d049-c1c9-9fd3-d47a63fd1aa3@selasky.org>
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Hi Matthew,
There is a deadlock when destroying VLANs after the epoch changes were
made. Can you have a look and consider the attached patch for 12-current?
Thank you!
--HPS
Thread 1:
> epoch_block_handler_preempt() at epoch_block_handler_preempt+0x90/frame 0xfffffe00261b3970
> ck_epoch_synchronize_wait() at ck_epoch_synchronize_wait+0x9d/frame 0xfffffe00261b39c0
> epoch_wait_preempt() at epoch_wait_preempt+0x170/frame 0xfffffe00261b3a20
> vlan_setmulti() at vlan_setmulti+0xb4/frame 0xfffffe00261b3a70
> vlan_ioctl() at vlan_ioctl+0x83/frame 0xfffffe00261b3ad0
> in6m_release_task() at in6m_release_task+0x32e/frame 0xfffffe00261b3b30
> gtaskqueue_run_locked() at gtaskqueue_run_locked+0xf9/frame 0xfffffe00261b3b80
> gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0x88/frame 0xfffffe00261b3bb0
> fork_exit() at fork_exit+0x84/frame 0xfffffe00261b3bf0
> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe00261b3bf0
> --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
Thread 2:
> sleepq_switch() at sleepq_switch+0x10d/frame 0xfffffe002bffd3f0
> sleepq_wait() at sleepq_wait+0x43/frame 0xfffffe002bffd420
> _sx_xlock_hard() at _sx_xlock_hard+0x4a6/frame 0xfffffe002bffd4c0
> _sx_xlock() at _sx_xlock+0xc1/frame 0xfffffe002bffd500
> in6_leavegroup() at in6_leavegroup+0x27/frame 0xfffffe002bffd520
> in6_purgeaddr() at in6_purgeaddr+0xc2/frame 0xfffffe002bffd6a0
> if_purgeaddrs() at if_purgeaddrs+0x11e/frame 0xfffffe002bffd750
> if_detach_internal() at if_detach_internal+0x709/frame 0xfffffe002bffd7d0
> if_detach() at if_detach+0x3d/frame 0xfffffe002bffd7f0
> vlan_clone_destroy() at vlan_clone_destroy+0x21/frame 0xfffffe002bffd820
> if_clone_destroyif() at if_clone_destroyif+0x175/frame 0xfffffe002bffd870
> if_clone_destroy() at if_clone_destroy+0x205/frame 0xfffffe002bffd8c0
> ifioctl() at ifioctl+0x582/frame 0xfffffe002bffd990
> kern_ioctl() at kern_ioctl+0x2ba/frame 0xfffffe002bffd9f0
> sys_ioctl() at sys_ioctl+0x15e/frame 0xfffffe002bffdac0
> amd64_syscall() at amd64_syscall+0x28c/frame 0xfffffe002bffdbf0
> fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe002bffdbf0
> --- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x80047b92a, rsp = 0x7fffffffe318, rbp = 0x7fffffffe330 ---
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Content-Type: text/x-patch;
name="vlan.diff"
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Content-Disposition: attachment;
filename="vlan.diff"
Index: sys/net/if_vlan.c
===================================================================
--- sys/net/if_vlan.c (revision 339234)
+++ sys/net/if_vlan.c (working copy)
@@ -153,6 +153,7 @@
struct vlan_mc_entry {
struct sockaddr_dl mc_addr;
CK_SLIST_ENTRY(vlan_mc_entry) mc_entries;
+ struct epoch_context mc_epoch_ctx;
};
struct ifvlan {
@@ -317,6 +318,13 @@
#define HASH(n, m) ((((n) >> 8) ^ ((n) >> 4) ^ (n)) & (m))
static void
+vlan_mc_free(struct epoch_context *ctx)
+{
+ struct vlan_mc_entry *mc = __containerof(ctx, struct vlan_mc_entry, mc_epoch_ctx);
+ free(mc, M_VLAN);
+}
+
+static void
vlan_inithash(struct ifvlantrunk *trunk)
{
int i, n;
@@ -572,8 +580,7 @@
while ((mc = CK_SLIST_FIRST(&sc->vlan_mc_listhead)) != NULL) {
CK_SLIST_REMOVE_HEAD(&sc->vlan_mc_listhead, mc_entries);
(void)if_delmulti(ifp_p, (struct sockaddr *)&mc->mc_addr);
- NET_EPOCH_WAIT();
- free(mc, M_VLAN);
+ epoch_call(net_epoch_preempt, &mc->mc_epoch_ctx, vlan_mc_free);
}
/* Now program new ones. */
@@ -1485,8 +1492,7 @@
error);
}
CK_SLIST_REMOVE_HEAD(&ifv->vlan_mc_listhead, mc_entries);
- NET_EPOCH_WAIT();
- free(mc, M_VLAN);
+ epoch_call(net_epoch_preempt, &mc->mc_epoch_ctx, vlan_mc_free);
}
vlan_setflags(ifp, 0); /* clear special flags on parent */
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