Am Montag, den 13.07.2015, 16:00 +0200 schrieb Richard Weinberger:
> Am 13.07.2015 um 15:58 schrieb Thomas Meyer:
> > Am Montag, den 13.07.2015, 15:52 +0200 schrieb Richard Weinberger:
> > > On Mon, Jul 13, 2015 at 3:41 PM, Thomas Meyer <tho...@m3y3r.de>
> > > wrote:
> > > > Hi,
> > > >
> > > > The uml_net network setup "fails" on my computer with:
> > > >
> > > > [ 15.930000] helper_wait : waitpid process 11673 failed,
> > > > errno =
> > > > 10
> > > > [ 15.930000] * modprobe tun
> > > > * ifconfig tap0 192.168.10.1 netmask
> > > > 255.255.255.255
> > > > up
> > > > * bash -c echo 1 > /proc/sys/net/ipv4/ip_forward
> > > > [ 20.480000] helper_wait : waitpid process 11780 failed,
> > > > errno =
> > > > 10
> > > > [ 20.480000] * route add -host 192.168.10.2 dev tap0
> > > > * bash -c echo 1 >
> > > > /proc/sys/net/ipv4/conf/tap0/proxy_arp
> > > >
> > > > because I run uml linux as a normal user and I guess these
> > > > commands
> > > > fail, because of insufficient rights:
> > > > bash -c echo 1 > /proc/sys/net/ipv4/ip_forward
> > > > bash -c echo 1 > /proc/sys/net/ipv4/conf/tap0/proxy_arp
> > > >
> > > > But this failure is okay for me, as firewalld, sets above
> > > > options
> > > > correctly on my host computer.
> > > >
> > > > The problem I see is that UML list two zombie processes:
> > > > 11780 root 20 0 0 0 0 Z 0.0 0.0
> > > > 0:00.00
> > > > 15:34 │ │ ├─ uml_net
> > > > 11673 root 20 0 0 0 0 Z 0.0 0.0
> > > > 0:00.00
> > > > 15:34 │ │ ├─ uml_net
> > > >
> > > > UML seems to never reap those two processes, likely because of
> > > > errno=10 exit code.
> > > >
> > > > any idea how to fix this?
> > >
> > > Hmm, it tries to reap them using waitpid().
> > > But it seems to fail with ECHILD.
> > >
> > > Can you add a few prints to compare the PIDs?
> >
> > Sure, where should I add those?
> > os-Linux/helper.c - helper_wait(int pid) ?
>
> Yeah. And please add a dump_stack() to figure out where it was
> called.
I think calling dump_stack() somehow changed the errno to 25?!
[ 19.600000] CPU: 0 PID: 282 Comm: ip Not tainted
4.2.0-rc1-00089-g1ee9c9e-dirty #256
[ 19.600000] Stack:
[ 19.600000] 6caf14a0 60089462 ffffffff00000013 7fa4a5ab3698
[ 19.600000] 00006b41 60028d90 6caf14b0 60623767
[ 19.600000] 6caf14f0 60040c0c 00000000 6caf1590
[ 19.600000] Call Trace:
[ 19.600000] [<606206d9>] ? printk+0x0/0x94
[ 19.600000] [<6002c85b>] show_stack+0xdb/0x1a0
[ 19.600000] [<60089462>] ? dump_stack_print_info+0xd2/0xf0
[ 19.600000] [<60623767>] dump_stack+0x2a/0x2c
[ 19.600000] [<60040c0c>] helper_wait+0x7c/0xd0
[ 19.600000] [<60044e5e>] tuntap_open_tramp.constprop.0+0x15e/0x270
[ 19.600000] [<60466a60>] ? dev_set_rx_mode+0x0/0x50
[ 19.600000] [<6004501f>] tuntap_open+0xaf/0x2d0
[ 19.600000] [<60044fdb>] ? tuntap_open+0x6b/0x2d0
[ 19.600000] [<6006f64f>] ? notifier_call_chain+0x4f/0x80
[ 19.600000] [<60466a60>] ? dev_set_rx_mode+0x0/0x50
[ 19.600000] [<60035ccd>] uml_net_open+0x2d/0x140
[ 19.600000] [<60466b57>] __dev_open+0xa7/0x130
[ 19.600000] [<60466a9e>] ? dev_set_rx_mode+0x3e/0x50
[ 19.600000] [<60466ee4>] __dev_change_flags+0xb4/0x1a0
[ 19.600000] [<60466ffb>] dev_change_flags+0x2b/0x70
[ 19.600000] [<6047a9c8>] do_setlink+0x318/0x8f0
[ 19.600000] [<603d24b9>] ? nla_parse+0x39/0x140
[ 19.600000] [<60045330>] ? run_syscall_stub+0xf0/0x350
[ 19.600000] [<6047b7ae>] rtnl_newlink+0x6ae/0xa10
[ 19.600000] [<60042ff0>] ? set_signals+0x0/0x50
[ 19.600000] [<60042d00>] ? change_sig+0x70/0x80
[ 19.600000] [<6004302f>] ? set_signals+0x3f/0x50
[ 19.600000] [<6034e227>] ? avc_has_perm_noaudit+0x57/0x120
[ 19.600000] [<6047bc34>] rtnetlink_rcv_msg+0x94/0x280
[ 19.600000] [<60042ff0>] ? set_signals+0x0/0x50
[ 19.600000] [<6047dda0>] ? sk_filter+0x0/0xe0
[ 19.600000] [<6044de30>] ? skb_pull+0x0/0x90
[ 19.600000] [<6047bba0>] ? rtnetlink_rcv_msg+0x0/0x280
[ 19.600000] [<6048db00>] ? netlink_ack+0x0/0x170
[ 19.600000] [<6048dd39>] netlink_rcv_skb+0xc9/0x100
[ 19.600000] [<6047dda0>] ? sk_filter+0x0/0xe0
[ 19.600000] [<6047bb8b>] rtnetlink_rcv+0x3b/0x50
[ 19.600000] [<6048d4dd>] netlink_unicast+0x1cd/0x2b0
[ 19.600000] [<6048da8e>] netlink_sendmsg+0x3ee/0x460
[ 19.600000] [<6034f3da>] ? selinux_socket_sendmsg+0x2a/0x30
[ 19.600000] [<60442c8a>] sock_sendmsg+0x3a/0x90
[ 19.600000] [<6044480a>] ___sys_sendmsg+0x30a/0x320
[ 19.600000] [<6004592a>] ? map+0x4a/0x50
[ 19.600000] [<600fc150>] ? handle_mm_fault+0x0/0x1590
[ 19.600000] [<6002dcd5>] ? handle_page_fault+0x265/0x350
[ 19.600000] [<6002e1fe>] ? segv+0x28e/0x3e0
[ 19.600000] [<60445b61>] __sys_sendmsg+0x51/0xa0
[ 19.600000] [<60445bc0>] SyS_sendmsg+0x10/0x20
[ 19.600000] [<6002ef3e>] handle_syscall+0x6e/0xa0
[ 19.600000] [<60046552>] userspace+0x3f2/0x4e0
[ 19.600000] [<6002f253>] ? do_op_one_page+0x153/0x240
[ 19.600000] [<60041a4f>] ? save_registers+0x1f/0x40
[ 19.600000] [<60049816>] ? arch_prctl+0x1f6/0x220
[ 19.600000] [<6002b065>] fork_handler+0x85/0x90
[ 19.600000] helper_wait : waitpid process 27457 failed, errno = 25
[ 19.600000] * modprobe tun
* ifconfig tap0 192.168.10.1 netmask 255.255.255.255 up
* bash -c echo 1 > /proc/sys/net/ipv4/ip_forward
[ 19.780000] ip (282) used greatest stack depth: 3616 bytes left
[ 24.120000] CPU: 0 PID: 305 Comm: ip Not tainted
4.2.0-rc1-00089-g1ee9c9e-dirty #256
[ 24.120000] Stack:
[ 24.120000] 6caab720 60089462 ffffffff00000014 7fa4a5ab3698
[ 24.120000] 00006b94 60028d90 6caab730 60623767
[ 24.120000] 6caab770 60040c0c 6caab8b0 70ac2000
[ 24.120000] Call Trace:
[ 24.120000] [<600d767e>] ? __free_pages+0x3e/0xa0
[ 24.120000] [<606206d9>] ? printk+0x0/0x94
[ 24.120000] [<6002c85b>] show_stack+0xdb/0x1a0
[ 24.120000] [<60089462>] ? dump_stack_print_info+0xd2/0xf0
[ 24.120000] [<60623767>] dump_stack+0x2a/0x2c
[ 24.120000] [<60040c0c>] helper_wait+0x7c/0xd0
[ 24.120000] [<60037233>] change+0x193/0x240
[ 24.120000] [<60571a40>] ? fib_magic.isra.1+0x0/0xd0
[ 24.120000] [<60044c00>] ? tuntap_add_addr+0x0/0x70
[ 24.120000] [<60037596>] open_addr+0x26/0x30
[ 24.120000] [<60044c5d>] tuntap_add_addr+0x5d/0x70
[ 24.120000] [<60571a40>] ? fib_magic.isra.1+0x0/0xd0
[ 24.120000] [<60048f40>] ? __memcpy+0x0/0x20
[ 24.120000] [<60035769>] uml_inetaddr_event+0x99/0xc0
[ 24.120000] [<6057302a>] ? fib_inetaddr_event+0x9a/0xc0
[ 24.120000] [<6006f64f>] notifier_call_chain+0x4f/0x80
[ 24.120000] [<6006fb64>] __blocking_notifier_call_chain+0x54/0x80
[ 24.120000] [<60476920>] ? rtnl_is_locked+0x0/0x20
[ 24.120000] [<6006fba8>] blocking_notifier_call_chain+0x18/0x20
[ 24.120000] [<605685e5>] __inet_insert_ifa+0x1a5/0x2d0
[ 24.120000] [<605690d9>] inet_rtm_newaddr+0x1e9/0x4c0
[ 24.120000] [<6047bc34>] rtnetlink_rcv_msg+0x94/0x280
[ 24.120000] [<60042ff0>] ? set_signals+0x0/0x50
[ 24.120000] [<6047dda0>] ? sk_filter+0x0/0xe0
[ 24.120000] [<6044de30>] ? skb_pull+0x0/0x90
[ 24.120000] [<6047bba0>] ? rtnetlink_rcv_msg+0x0/0x280
[ 24.120000] [<6048db00>] ? netlink_ack+0x0/0x170
[ 24.120000] [<6048dd39>] netlink_rcv_skb+0xc9/0x100
[ 24.120000] [<6047dda0>] ? sk_filter+0x0/0xe0
[ 24.120000] [<6047bb8b>] rtnetlink_rcv+0x3b/0x50
[ 24.120000] [<6048d4dd>] netlink_unicast+0x1cd/0x2b0
[ 24.120000] [<6048da8e>] netlink_sendmsg+0x3ee/0x460
[ 24.120000] [<6034f3da>] ? selinux_socket_sendmsg+0x2a/0x30
[ 24.120000] [<60442c8a>] sock_sendmsg+0x3a/0x90
[ 24.120000] [<6044480a>] ___sys_sendmsg+0x30a/0x320
[ 24.120000] [<6004592a>] ? map+0x4a/0x50
[ 24.120000] [<600fc150>] ? handle_mm_fault+0x0/0x1590
[ 24.120000] [<6002dcd5>] ? handle_page_fault+0x265/0x350
[ 24.120000] [<6002e1fe>] ? segv+0x28e/0x3e0
[ 24.120000] [<60445b61>] __sys_sendmsg+0x51/0xa0
[ 24.120000] [<60445bc0>] SyS_sendmsg+0x10/0x20
[ 24.120000] [<6002ef3e>] handle_syscall+0x6e/0xa0
[ 24.120000] [<60046552>] userspace+0x3f2/0x4e0
[ 24.120000] [<6002f253>] ? do_op_one_page+0x153/0x240
[ 24.120000] [<60041a4f>] ? save_registers+0x1f/0x40
[ 24.120000] [<60049816>] ? arch_prctl+0x1f6/0x220
[ 24.120000] [<6002b065>] fork_handler+0x85/0x90
[ 24.120000] helper_wait : waitpid process 27540 failed, errno = 25
[ 24.120000] * route add -host 192.168.10.2 dev tap0
* bash -c echo 1 > /proc/sys/net/ipv4/conf/tap0/proxy_arp
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index e3ee4a5..683460f 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -14,6 +14,8 @@
#include <os.h>
#include <um_malloc.h>
+extern __attribute__((regparm(0))) void dump_stack(void);
+
struct helper_data {
void (*pre_exec)(void*);
void *pre_data;
@@ -152,6 +154,7 @@ int helper_wait(int pid)
CATCH_EINTR(ret = waitpid(pid, &status, wflags));
if (ret < 0) {
+ dump_stack();
printk(UM_KERN_ERR "helper_wait : waitpid process %d
failed, "
"errno = %d\n", pid, errno);
return -errno;
------------------------------------------------------------------------------
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