Date: Fri, 25 Oct 2019 14:11:55 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 241489] netmap + if_vlan panics related to 'Widen NET_EPOCH coverage' work (r353292) Message-ID: <bug-241489-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D241489 Bug ID: 241489 Summary: netmap + if_vlan panics related to 'Widen NET_EPOCH coverage' work (r353292) Product: Base System Version: CURRENT Hardware: amd64 OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: aleksandr.fedorov@itglobal.com We widely use the configuration: vm (bhyve) - vale switch - if_vlan. After r353292 we observe the following panic: Unread portion of the kernel message buffer: panic: Assertion in_epoch(net_epoch_preempt) failed at /afedorov/vstack-develop-freebsd/sys/net/if_vlan.c:1142 cpuid =3D 11 time =3D 1572003077 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe01d541d= 1e0 vpanic() at vpanic+0x17e/frame 0xfffffe01d541d240 panic() at panic+0x43/frame 0xfffffe01d541d2a0 vlan_transmit() at vlan_transmit+0x165/frame 0xfffffe01d541d2f0 nm_os_generic_xmit_frame() at nm_os_generic_xmit_frame+0x7c/frame 0xfffffe01d541d310 generic_netmap_txsync() at generic_netmap_txsync+0x2d6/frame 0xfffffe01d541= d3e0 netmap_bwrap_notify() at netmap_bwrap_notify+0x96/frame 0xfffffe01d541d410 nm_vale_flush() at nm_vale_flush+0xa53/frame 0xfffffe01d541d510 netmap_vale_vp_txsync() at netmap_vale_vp_txsync+0x508/frame 0xfffffe01d541= d5a0 netmap_ioctl() at netmap_ioctl+0x1b4/frame 0xfffffe01d541d670 freebsd_netmap_ioctl() at freebsd_netmap_ioctl+0x88/frame 0xfffffe01d541d6b0 devfs_ioctl() at devfs_ioctl+0xca/frame 0xfffffe01d541d700 VOP_IOCTL_APV() at VOP_IOCTL_APV+0x85/frame 0xfffffe01d541d720 vn_ioctl() at vn_ioctl+0x13d/frame 0xfffffe01d541d830 devfs_ioctl_f() at devfs_ioctl_f+0x1e/frame 0xfffffe01d541d850 kern_ioctl() at kern_ioctl+0x295/frame 0xfffffe01d541d8b0 sys_ioctl() at sys_ioctl+0x15c/frame 0xfffffe01d541d980 amd64_syscall() at amd64_syscall+0x2b5/frame 0xfffffe01d541dab0 fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe01d541dab0 --- syscall (54, FreeBSD ELF64, sys_ioctl), rip =3D 0x800819c2a, rsp =3D 0x7fffdfffce68, rbp =3D 0x7fffdfffcef0 --- Uptime: 19m12s Dumping 5033 out of 65374 MB:..1%..11%..21%..31%..41%..51%..61%..71%..81%..= 91% The problem is that NET_EPOCH_ENTER() is moved out of the vlan_transmit() function. But the netmap generic code calls the vlan_transmit () function directly from nm_os_generic_xmit_frame (), without entering to the EPOCH section. So, kernel panics on NET_EPOCH_ASSERT(). Temporarily, I solved the problem with the following patch, but I'm not sur= e if this is the correct solution. --- a/sys/dev/netmap/netmap_freebsd.c +++ b/sys/dev/netmap/netmap_freebsd.c @@ -420,6 +420,7 @@ nm_os_generic_xmit_frame(struct nm_os_gen_arg *a) { int ret; u_int len =3D a->len; + struct epoch_tracker et; struct ifnet *ifp =3D a->ifp; struct mbuf *m =3D a->m; @@ -453,9 +454,11 @@ nm_os_generic_xmit_frame(struct nm_os_gen_arg *a) M_HASHTYPE_SET(m, M_HASHTYPE_OPAQUE); m->m_pkthdr.flowid =3D a->ring_nr; m->m_pkthdr.rcvif =3D ifp; /* used for tx notification */ + NET_EPOCH_ENTER(et); CURVNET_SET(ifp->if_vnet); ret =3D NA(ifp)->if_transmit(ifp, m); CURVNET_RESTORE(); + NET_EPOCH_EXIT(et); return ret ? -1 : 0; } --=20 You are receiving this mail because: You are the assignee for the bug.=
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