Bug 89197

First read: http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=82820

Because i could not add additional comments because i get an error message 
about illegally trying to change the component field (which i did not) i have 
to enter a new report for this!!

This is the same problem as:

            http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=8282
------------------------------------------------------------------------------

Kernel: 2.4.20-9 on (P-II-233 Mhz)
Samba : 2.2.7a-8.9.0 (but also reproducable with 2.2.8a-1 and 3.0alpha23)

I have exactly the same problem in 33% of the case mount hangs. two times it 
succeeds and the third time it fails. This is random behaviour because 
sometimes it succeeds more often and sometimes it always hangs. Very annoying 
because i call mount from backup scripts.

B.t.w. The command itself hangs but only at the very very end. When you press 
CTRL-C and return to the prompt you can work with the share as normal. It is 
not mount that hangs. It is the smbmount that hangs. When you issue smbmount 
directly the same problem is reproducable. Here i can reproduce it on two 
machine, both upgraded to RH 9. I didn't have this on RH 8. All upgraded to 
the latest patches. One machine tries to mount a WIN2000 server share. The 
other machine tries to mount a WinXP Pro share. Both hang in more than 33% of 
the cases.

Like it has been said before when you do a ps -Al in another window while it 
hangs you see the following related processes:

0 S     0 26041 25701  0  76   0    -   917 wait4  pts/0    00:00:00 mount
4 S     0 26042 26041  0  83   0    -   682 schedu pts/0    00:00:00 
mount.smbfs
1 S     0 26043 26042  0  83   0    -   650 pause  ?        00:00:00 
mount.smbfs

After i have pressed CTRL-C in the mount window OR when the command was 
succesfull the "schedu" process and the mount process itself are not there any 
longer. When it hangs and i manually kill the "schedu" command it the mount 
command exits as well and i can use the share normally as well. So it seems it 
hangs on that "schedu" process.

I also made straces. Maybe that also provides some information. Even on the 
highest debug level all system commands excute succesfully only when it hangs 
it hangs on the very last wait4 statement where it waits for the child process 
to exit, which it sometimes never does. WHen i use the -f option for even more 
detailed output i see 

[pid 25798] rt_sigaction(SIGUSR1, {0x804b120, [USR1], 
SA_RESTORER|SA_RESTART, 0x420276f8}, NULL, 8) = 0
[pid 25798] pause(

as the very last line of strace. 

Now this triggered me because in the samba syslog (smbd.log) i get the 
following error message at random times:

[2003/04/20 11:28:58, 0] smbd/oplock_linux.c:linux_init_kernel_oplocks(287)
  Failed to setup RT_SIGNAL_LEASE handler

BUT:
1) Only on one of the failed machines. On the other machine where mount also 
hangs the syslog doesn't show this error at all.
2) It doesn't appear when i issue the hanging mount command. It appears at 
random times in the syslog. Like in the middle of the night when there is no 
activity at all.

Also when i add the -f flag to strace the mount -always- hangs in 100% of the 
cases. So is it a kernel timing related problem? When i remove the strace -f 
the mount sometimes succeeds again.

For completeness i add the complete straces below. Hope this helps in the 
debugging problem. If you want you can get a login on my machine to debug it 
further. Let me know if you need that.

Thanks,
Jan

======================================================
Output of strace where mount returns normally:
======================================================
umask(022)                              = 022
open("/dev/null", O_RDWR|O_LARGEFILE)   = 3
close(3)                                = 0
getuid32()                              = 0
geteuid32()                             = 0
lstat64("/etc/mtab", {st_mode=S_IFREG|0644, st_size=326, ...}) = 0
stat64("/sbin/mount.smbfs", {st_mode=S_IFREG|0755, st_size=574846, ...}) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|0x11, 
<ignored>, <ignored>, 0x400212c8) = 25739
wait4(-1, [WIFEXITED(s) && WEXITSTATUS(s) == 0], 0, NULL) = 25739
exit_group(0)  

======================================================
Output of strace where mount hangs at the end:
======================================================
umask(022)                              = 022
open("/dev/null", O_RDWR|O_LARGEFILE)   = 3
close(3)                                = 0
getuid32()                              = 0
geteuid32()                             = 0
lstat64("/etc/mtab", {st_mode=S_IFREG|0644, st_size=326, ...}) = 0
stat64("/sbin/mount.smbfs", {st_mode=S_IFREG|0755, st_size=574846, ...}) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|0x11, 
<ignored>, <ignored>, 0x400212c8) = 25746
wait4(-1, 

======================================================
Like you can see the wait4 line isn't finished even in
this output:
If i dig further with the strace -f option:
======================================================
[pid 25798] wait4(-1,  <unfinished ...>
[pid 25799] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 25799] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 25799] stat64("/usr/bin/smbmnt", {st_mode=S_IFREG|0755, 
st_size=561294, ...}) = 0
[pid 25799] execve("/usr/bin/smbmnt", ["smbmnt", "/mnt/backup", "-
s", "//Cdserver/Leerling", "-o", ""], [/* 34 vars */]) = 0
[pid 25799] uname({sys="Linux", node="pandora.augustinusschool.nl", ...}) = 0
........ <snip> .............
[pid 25798] open("/var/log/samba/smbmount.log", 
O_WRONLY|O_APPEND|O_CREAT|O_LARGEFILE, 0666) = 0
[pid 25798] fstat64(0, {st_mode=S_IFREG|0644, st_size=35818, ...}) = 0
[pid 25798] mmap2(NULL, 4096, PROT_READ|PROT_WRITE, 
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
[pid 25798] fstat64(0, {st_mode=S_IFREG|0644, st_size=35818, ...}) = 0
[pid 25798] _llseek(0, 35818, [35818], SEEK_SET) = 0
[pid 25798] munmap(0x40017000, 4096)    = 0
[pid 25798] umask(022)                  = 022
[pid 25798] time(NULL)                  = 1050740324
[pid 25798] geteuid32()                 = 0
[pid 25798] write(0, "[2003/04/19 10:18:44, 0] client/"..., 63) = 63
[pid 25798] getpid()                    = 25798
[pid 25798] geteuid32()                 = 0
[pid 25798] write(0, "  mount.smbfs: entering daemon m"..., 79) = 79
[pid 25798] rt_sigaction(SIGUSR1, {0x804b120, [USR1], SA_RESTORER|SA_RESTART, 
0x420276f8}, NULL, 8) = 0
[pid 25798] pause(

======================================================
And again the mount command hangs at the end (pause line 
unfinished in the strace output).