While attempting to narrow down the syscalls used to hit 126537 
using iogen/doio I hit the following assertion in lock_dlm: 
 
(6 node cluster, all nodes running: iogen -o -m random -s 
write,writev,readv -t 1b -T1000b 10000b:tfile1  | doio -avk) 
 
  k 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex e680f-12eb12 5892 w 1 
ex plock 5892 error 0 
en punlock 5892 7,40a9f03 
remove 7,40a9f03 5892 
ex punlock 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex 100753-1719bd 5892 w 1 
ex plock 5892 error 0 
en punlock 5892 7,40a9f03 
remove 7,40a9f03 5892 
ex punlock 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex 15e7ad-1b1306 5892 w 1 
ex plock 5892 error 0 
en punlock 5892 7,40a9f03 
remove 7,40a9f03 5892 
ex punlock 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex 177959-1e4de3 5892 w 1 
ex plock 5892 error 0 
en punlock 5892 7,40a9f03 
remove 7,40a9f03 5892 
ex punlock 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex 123e6f-188ee0 5892 w 1 
ex plock 5892 error 0 
en punlock 5892 7,40a9f03 
remove 7,40a9f03 5892 
ex punlock 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex 12a7f1-135265 5892 w 1 
ex plock 5892 error 0 
en punlock 5892 7,40a9f03 
remove 7,40a9f03 5892 
ex punlock 5892 error 0 
en plock 5892 7,40a9f03 
req 7,40a9f03 ex 41eb3-b9c4c 5892 w 1 
 
lock_dlm:  Assertion failed on line 272 of file 
fs/gfs_locking/lock_dlm/lock.c 
lock_dlm:  assertion:  "!error" 
lock_dlm:  time = 106036030 
gfs0: error=-16 num=11,40a9f03 
 
Kernel panic: lock_dlm:  Record message above and reboot. 
 
This then caused all the nodes to fail with stacks which look just 
like recovery bug 126604. 
 
Version-Release number of selected component (if applicable): 
 
 
How reproducible: 
Didn't try, yet 
 
Steps to Reproduce: 
1.iogen -o -m random -s write,writev,readv -t 1b -T1000b 
10000b:tfile1  | doio -avk  on all nodes in your cluster in a gfs 
fs. 
 
2. 
3. 
     
 
Additional info: