Menu
What's new
By:
Filters Better Search

My experience with the RT-AC86U

  • SNBForums Code of Conduct

    SNBForums is a community for everyone, no matter what their level of experience.

    Please be tolerant and patient of others, especially newcomers. We are all here to share and learn!

    The rules are simple: Be patient, be nice, be helpful or be gone!

So would you recommend letting the script lock up... then running an strace on the hung "nvram get" PID to examine the hung process further?
 
Code: 
bind(3, {sa_family=AF_NETLINK, nl_pid=1098, nl_groups=00000000}, 12) = -1 EADDRINUSE (Address already in use)
The difference.
 
Viktor Jaep said:
So would you recommend letting the script lock up... then running an strace on the hung "nvram get" PID to examine the hung process further?
Click to expand...
I ran watch -n 0 strace -r nvram get wan0_enable
 
dave14305 said:
I ran watch -n 0 strace -r nvram get wan0_enable
Click to expand...
I guess I could run 5 different watch windows to monitor each of the vpnclient# state nvram values to see which one it randomly hangs on?
 
Viktor Jaep said:
I guess I could run 5 different watch windows to monitor each of the vpnclient# state nvram values to see which one it randomly hangs on?
Click to expand...
It doesn’t really matter what variable you choose, as best as I can tell.
 
Well... I dunno. I didn't see a way to control the output of this strace info... it was flying across my screen. The vpn_client3_state locked, but the strace window monitoring that nvram command just kept on going. Not quite sure how to handle this.
 
Viktor Jaep said:
Well... I dunno. I didn't see a way to control the output of this strace info... it was flying across my screen. The vpn_client3_state locked, but the strace window monitoring that nvram command just kept on going. Not quite sure how to handle this.
Click to expand...
It will keep redrawing until the watched command hangs. I wasn’t getting anywhere with a 1 second interval so I went to 0. But that makes it harder to stop the watch loop when you want to ctrl-c. It ends the hung nvram command and starts a new one. So I kill the watch pid in another window and copy/paste the last output in the other window.
 
dave14305 said:
It will keep redrawing until the watched command hangs. I wasn’t getting anywhere with a 1 second interval so I went to 0. But that makes it harder to stop the watch loop when you want to ctrl-c. It ends the hung nvram command and starts a new one. So I kill the watch pid in another window and copy/paste the last output in the other window.
Click to expand...
Yeah, I was not able to ctrl-c out of that...
 
Here's an example of an nvram wrapper. Realize I quite literally threw this together a few minutes ago. So it might need some refinement. But I just wanted to provide a quick-n-dirty example.

Bash: 
#!/bin/sh

# copy original nvram executable to /tmp
cp /usr/sbin/nvram /tmp/_nvram

# create nvram wrapper that calls original nvram executable in /tmp
cat << 'EOF' > /tmp/nvram
#!/bin/sh
#set -x # comment/uncomment to disable/enable debug mode

# required for serialization when reentry is possible
LOCK="/tmp/$(basename $0).lock"
acquire_lock() { until mkdir $LOCK &>/dev/null; do sleep 2; done; }
release_lock() { rmdir $LOCK &>/dev/null; }

# one instance at a time
acquire_lock

# catch premature exit and cleanup
trap 'release_lock; exit 1' SIGHUP SIGINT SIGTERM

/tmp/_nvram $@

rc=$?

# any concurrent instance(s) may now run
release_lock

exit $rc
EOF
chmod +x /tmp/nvram

# replace nvram in /usr/sbin w/ nvram wrapper in /tmp
mount -o bind /tmp/nvram /usr/sbin/nvram

The idea is to FORCE every reference to the nvram executable threw the above script, which enforces one-at-a-time semantics.
 
Last edited:
I repeated the test with a wl command and it sees the same address in use message when it hangs.
Code: 
Every 0s: strace -r wl -i eth5 noise                                                                       2022-06-14 20:07:33

     0.000000 execve("/usr/sbin/wl", ["wl", "-i", "eth5", "noise"], 0x7fe50f5f30 /* 18 vars */ <unfinished ...>
     0.000662 [ Process PID=1163 runs in 32 bit mode. ]
strace: WARNING: Proper structure decoding for this personality is not supported, please consider building strace with mpers support enabled.
     0.000040 <... execve resumed>)     = 0
     0.000066 brk(NULL)                 = 0x82f000
     0.000057 uname({sysname="Linux", nodename="router", ...}) = 0
     0.000096 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xf72fa000
     0.000064 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
     0.000127 open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
     0.000068 fstat64(3, 0xffd6d570)    = 0
     0.000319 mmap2(NULL, 10528, PROT_READ, MAP_PRIVATE, 3, 0) = 0xf72f7000
     0.000044 close(3)                  = 0
     0.000053 open("/lib/libnvram.so", O_RDONLY|O_CLOEXEC) = 3
     0.000050 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\08\t\0\0004\0\0\0"..., 512) = 512
     0.000051 fstat64(3, 0xffd6d5b0)    = 0
     0.000041 mmap2(NULL, 69528, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xf72bb000
     0.000047 mprotect(0xf72bc000, 61440, PROT_NONE) = 0
     0.000049 mmap2(0xf72cb000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0) = 0xf72cb000
     0.000058 close(3)                  = 0
     0.000045 open("/lib/libwlcsm.so", O_RDONLY|O_CLOEXEC) = 3
     0.000048 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\200\34\0\0004\0\0\0"..., 512) = 512
     0.000047 fstat64(3, 0xffd6d598)    = 0
     0.000038 mmap2(NULL, 90092, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xf72a5000
     0.000044 mprotect(0xf72aa000, 61440, PROT_NONE) = 0
     0.000046 mmap2(0xf72b9000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x4000) = 0xf72b9000
     0.000067 close(3)                  = 0
     0.000046 open("/usr/lib/libshared.so", O_RDONLY|O_CLOEXEC) = 3
     0.000050 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\214X\1\0004\0\0\0"..., 512) = 512
     0.000048 fstat64(3, 0xffd6d580)    = 0
     0.000038 mmap2(NULL, 646528, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xf7207000
     0.000044 mprotect(0xf7274000, 65536, PROT_NONE) = 0
     0.000047 mmap2(0xf7284000, 45056, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6d000) = 0xf7284000
     0.000059 mmap2(0xf728f000, 89472, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xf728f000
     0.000060 close(3)                  = 0
     0.000054 open("/lib/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
     0.000047 read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0xm\1\0004\0\0\0"..., 512) = 512
     0.000048 fstat64(3, 0xffd6d568)    = 0
     0.000038 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xf72f6000
     0.000047 mmap2(NULL, 1299824, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xf70c9000
     0.000045 mprotect(0xf71f1000, 65536, PROT_NONE) = 0
     0.000052 mmap2(0xf7201000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x128000) = 0xf7201000
     0.000059 mmap2(0xf7204000, 9584, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xf7204000
     0.000056 close(3)                  = 0
     0.000061 open("/lib/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
     0.000050 read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\\I\0\0004\0\0\0"..., 512) = 512
     0.000048 fstat64(3, 0xffd6d460)    = 0
     0.000038 mmap2(NULL, 164436, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xf70a0000
     0.000045 mprotect(0xf70b5000, 65536, PROT_NONE) = 0
     0.000050 mmap2(0xf70c5000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15000) = 0xf70c5000
     0.000060 mmap2(0xf70c7000, 4692, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xf70c7000
     0.000055 close(3)                  = 0
     0.000073 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xf72f5000
     0.000048 set_tls(0xf72f54c0)       = 0
     0.000257 mprotect(0xf7201000, 8192, PROT_READ) = 0
     0.000088 mprotect(0xf70c5000, 4096, PROT_READ) = 0
     0.000298 mprotect(0xf72fb000, 4096, PROT_READ) = 0
     0.000051 munmap(0xf72f7000, 10528) = 0
     0.000050 set_tid_address(0xf72f5068) = 1163
     0.000036 set_robust_list(0xf72f5070, 12) = 0
     0.000052 rt_sigaction(SIGRTMIN, {sa_handler=0xf70a4278, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO, sa_restorer=0xf70f5b10}, NULL, 8) = 0
     0.000063 rt_sigaction(SIGRT_1, {sa_handler=0xf70a435c, sa_mask=[], sa_flags=SA_RESTORER|SA_RESTART|SA_SIGINFO, sa_restorer=0xf70f5b10}, NULL, 8) = 0
     0.000064 rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0
     0.000059 ugetrlimit(RLIMIT_STACK, {rlim_cur=2048*1024, rlim_max=RLIM_INFINITY}) = 0
     0.000215 socket(AF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
     0.000077 ioctl(3, SIOCDEVPRIVATE, 0xffd6db00) = 0
     0.000257 close(3)                  = 0
     0.000055 socket(AF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
     0.000041 ioctl(3, SIOCDEVPRIVATE, 0xffd6db00) = 0
     0.000149 close(3)                  = 0
     0.000069 stat64("/jffs", 0xffd6d9a8) = 0
     0.000055 stat64("/jffs/nvram_war", 0xffd6d9a8) = 0
     0.000086 socket(AF_NETLINK, SOCK_RAW, 0x1f /* NETLINK_??? */) = 3
     0.000055 bind(3, {sa_family=AF_NETLINK, nl_pid=1163, nl_groups=00000000}, 12) = -1 EADDRINUSE (Address already in use)
     0.000137 brk(NULL)                 = 0x82f000
     0.000038 brk(0x850000)             = 0x850000
     0.000056 sendmsg(3, {msg_name=0xcffd6da38, msg_namelen=-2696656, msg_iov=NULL, msg_iovlen=0, msg_control=0xf72b9d7400090dd4, msg_controllen=3505436194745028, msg_flags=MSG_WAITALL|MSG_FIN|MSG_CONFIRM|MSG_RST|MSG_NOSIGNAL|MSG_MORE|MSG_SENDPAGE_NOTLAST|MSG_BATCH|MSG_ZEROCOPY|MSG_FASTOPEN|MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT|0x1bd00000}, 0) = 36
     0.000148 recvmsg(3,
 
@Viktor Jaep if you are up for one more test then here is an interesting one to test concurrency.

Code: 
#!/bin/sh
trap '' HUP INT QUIT ABRT TERM
(i="0"
while true; do
  i="$(( i + 1 ))";
  for nv in 1 2 3 4 5; do
    unset "state${nv}";
    [ "$(ps -T | grep "nvram get" | wc -l )" -le "1" ] && eval "state${nv}"="$(/bin/nvram get vpn_client${nv}_state)";
  done
  clear
  echo "$state1" "$state2" "$state3" "$state4" "$state5"
  echo "$i"
done) > /tmp/mynvramerror.log 2>&1 &
exit 0
 
eibgrad said:
Here's an example of an nvram wrapper. Realize I quite literally threw this together a few minutes ago. So it might need some refinement. But I just wanted to provide a quick-n-dirty example.

Bash: 
#!/bin/sh

# copy original nvram executable to /tmp
cp /usr/sbin/nvram /tmp/_nvram

# create nvram wrapper that calls original nvram executable in /tmp
cat << 'EOF' > /tmp/nvram
#!/bin/sh
#set -x # comment/uncomment to disable/enable debug mode

# required for serialization when reentry is possible
LOCK="/tmp/$(basename $0).lock"
acquire_lock() { until mkdir $LOCK &>/dev/null; do sleep 2; done; }
release_lock() { rmdir $LOCK &>/dev/null; }

# one instance at a time
acquire_lock

# catch premature exit and cleanup
trap 'release_lock; exit 1' SIGHUP SIGINT SIGTERM

/tmp/_nvram $@

rc=$?

# any concurrent instance(s) may now run
release_lock

exit $rc
EOF
chmod +x /tmp/nvram

# replace nvram in /usr/sbin w/ nvram wrapper in /tmp
mount -o bind /tmp/nvram /usr/sbin/nvram

The idea is to FORCE every reference to the nvram executable threw the above script, which enforces one-at-a-time semantics.
Click to expand...
I figured you were going to go into lock file semantics, but mine are much simpler. However here we are talking about concurrent runs of nvram from separate parents and process's. therefore wouldn't our lock need to be applied to nvram process itself and not just the wrapper for one parent process?
 
SomeWhereOverTheRainBow said:
I figured you were going to go into lock file semantics, but mine are much simpler. However here we are talking about concurrent runs of nvram from separate parents and process's. therefore wouldn't our lock need to be applied to nvram process itself?
Click to expand...

If the parent process (nvram script) is serialized, then so is the child process (nvram executable).
 
eibgrad said:
If the parent process (nvram script) is serialized, then so is the child process (nvram executable).
Click to expand...
That is if we account for the path of nvram to be to the serialized process? Help me here I am only trying to understand. I use something similar to manage one of my loops.


Code: 
AdGuardHome_Run () {
  local lock_dir
  local pid_file
  lock_dir="/tmp/AdGuardHome"
  pid_file="${lock_dir}/pid"
  if ( mkdir ${lock_dir} ) 2> /dev/null; then
    printf "%s\n" "$$" > $pid_file
    trap 'rm -rf "$lock_dir"; exit $?' EXIT
    start="$(date +%s)"
    $1
    end="$(date +%s)"
    runtime="$((end-start))"
    logger -st "$NAME" "$1 took $runtime second(s) to complete."
    rm -rf "$lock_dir"
  else
    logger -st "$NAME" "Lock owned by $(cat $pid_file) exists; preventing duplicate runs!"
  fi
}
 
That is if we account for the path of nvram to be to the serialized process? Help me here I am only trying to understand. I use something similar to manage one of my loops.
SomeWhereOverTheRainBow said:
Code: 
AdGuardHome_Run () {
  local lock_dir
  local pid_file
  lock_dir="/tmp/AdGuardHome"
  pid_file="${lock_dir}/pid"
  if ( mkdir ${lock_dir} ) 2> /dev/null; then
    printf "%s\n" "$$" > $pid_file
    trap 'rm -rf "$lock_dir"; exit $?' EXIT
    start="$(date +%s)"
    $1
    end="$(date +%s)"
    runtime="$((end-start))"
    logger -st "$NAME" "$1 took $runtime second(s) to complete."
    rm -rf "$lock_dir"
  else
    logger -st "$NAME" "Lock owned by $(cat $pid_file) exists; preventing duplicate runs!"
  fi
}
Click to expand...

What I'm serializing is the ability to create the lock, which is the directory /tmp/nvram.lock. That's an atomic operation.
 
eibgrad said:
That is if we account for the path of nvram to be to the serialized process? Help me here I am only trying to understand. I use something similar to manage one of my loops.


What I'm serializing is the ability to create the lock, which is the directory /tmp/nvram.lock. That's an atomic operation.
Click to expand...
Now you are being more precise. I appreciate it. You cleared it up more.
 
eibgrad said:
That is if we account for the path of nvram to be to the serialized process? Help me here I am only trying to understand. I use something similar to manage one of my loops.


What I'm serializing is the ability to create the lock, which is the directory /tmp/nvram.lock. That's an atomic operation.
Click to expand...
I use a similar method to limit how many times my adguardhome can be called to start from a loop. I only wish the routers allowed trapping of the 'ERR'
 
SomeWhereOverTheRainBow said:
@Viktor Jaep if you are up for one more test then here is an interesting one to test concurrency.

Code: 
#!/bin/sh
trap '' HUP INT QUIT ABRT TERM
(i="0"
while true; do
  i="$(( i + 1 ))";
  for nv in 1 2 3 4 5; do
    unset "state${nv}";
    [ "$(ps -T | grep "nvram get" | wc -l )" -le "1" ] && eval "state${nv}"="$(/bin/nvram get vpn_client${nv}_state)";
  done
  clear
  echo "$state1" "$state2" "$state3" "$state4" "$state5"
  echo "$i"
done) > /tmp/mynvramerror.log 2>&1 &
exit 0
Click to expand...
Well, that's a weird one... not quite sure if it worked correctly or not... but for most of the log, each line was blank... Every so often, you would see an indication that it tried to do an nvram get call:

1655255440862.png
 
Viktor Jaep said:
Well, that's a weird one... not quite sure if it worked correctly or not... but for most of the log, each line was blank... Every so often, you would see an indication that it tried to do an nvram get call:

View attachment 41881
Click to expand...
maybe the CPU timing is wrong.. Something is seriously wrong if it cannot get past that.

try this?

Code: 
#!/bin/sh
trap '' HUP INT QUIT ABRT TERM
(i="0"
while true; do
  i="$(( i + 1 ))";
  for nv in 1 2 3 4 5; do
    unset "state${nv}";
    [ "$(ps -T | grep "nvram get" | wc -l )" -le "2" ] && eval "state${nv}"="$(/bin/nvram get vpn_client${nv}_state)";
  done
  clear
  echo "$state1" "$state2" "$state3" "$state4" "$state5"
  echo "$i"
done) > /tmp/mynvramerror.log 2>&1 &
exit 0

or

Code: 
#!/bin/sh
trap '' HUP INT QUIT ABRT TERM
(i="0"
until [ "$(ps -T | grep "nvram get" | wc -l )" -gt "2" ]; do
  i="$(( i + 1 ))";
  for nv in 1 2 3 4 5; do
    unset "state${nv}";
    [ "$(ps -T | grep "nvram get" | wc -l )" -le "2" ] && eval "state${nv}"="$(/bin/nvram get vpn_client${nv}_state)";
  done
  clear
  echo "$state1" "$state2" "$state3" "$state4" "$state5"
  echo "$i"
done) > /tmp/mynvramerror.log 2>&1 &
exit 0
 
Last edited:
You must log in or register to reply here.

Similar threads

nospamever
Happy and sad for RT-AC86U
Replies
10
Views
866
bibikalka
B
GShlomi
Sharing my DualWan with port forwarding and DDNS experience
Replies
0
Views
416
GShlomi
GShlomi
bengalih
Bug with corrupted passwords in OpenVPN Server
Replies
14
Views
924
gk802
G
U
Issue with GT-AXE11000 firmware not saving. /data partition mounting in read-only.
2
Replies
24
Views
2K
McKey
McKey
B
Router temperatures - 2023
2 3
Replies
44
Views
5K
coxhaus
C
Similar threads
Thread starter Title Forum Replies Date
GShlomi Sharing my DualWan with port forwarding and DDNS experience Asuswrt-Merlin 0
B Unable to establish VPN connection to my PiVPN (ovpn) from my Asus RT-AC86U running Asuswrt-Merlin 386.14 Asuswrt-Merlin 1
C Need info on bringing AC86U back to life as AIMesh unit Asuswrt-Merlin 3
D VPN director issue on RT-AC86U (386.14 Merlin FW) Asuswrt-Merlin 9
nospamever Happy and sad for RT-AC86U Asuswrt-Merlin 10
H Extremely low speed on ac86u with openvpn client Asuswrt-Merlin 7
P EoL RT-AC86U replacement Asuswrt-Merlin 4
H GT-AC29000 and AC86U mesh together Asuswrt-Merlin 10
M RT-AC86U Errors after latest firmware update (386.14) Asuswrt-Merlin 3
criskoe Asus RT-AC86U Openvpn connected but not working Asuswrt-Merlin 9

Similar threads

Latest threads

Support SNBForums w/ Amazon

If you'd like to support SNBForums, just use this link and buy anything on Amazon. Thanks!

Sign Up For SNBForums Daily Digest

Get an update of what's new every day delivered to your mailbox. Sign up here!

Members online

Total: 575 (members: 18, guests: 557)
Top