+++ This bug was initially created as a clone of Bug #1242041 +++

Description of problem:

Version-Release number of selected component (if applicable):

mainline
How reproducible:
always

Steps to Reproduce:
1.Create a volume
2.Export the volume using nfs-ganesha 
3.Mount the volume using nfsv4 protocol
4.set nfs4_acl on same file twice. 
nfs4_setfacl -a "A::<user_name>:<perm_set>" <filepath>

Actual results:
The brick got crashed.

Expected results:
It should succeed

Additional info:

back trace of brick process crash

#0  0x00007fd3339ba8e2 in posix_acl_ctx_update (inode=0x7fd33407275c, this=0x7fd334011fc0, buf=0x7fd331391800) at posix-acl.c:766
#1  0x00007fd3339c16d9 in posix_acl_setattr_cbk (frame=0x7fd328000d9c, cookie=0x7fd32800169c, this=0x7fd334011fc0, op_ret=0, op_errno=0, 
    prebuf=0x7fd331391870, postbuf=0x7fd331391800, xdata=0x0) at posix-acl.c:1762
#2  0x00007fd333de9a5d in changelog_setattr_cbk (frame=0x7fd32800169c, cookie=0x7fd3280028ac, this=0x7fd33400ee20, op_ret=0, op_errno=0, 
    preop_stbuf=0x7fd331391870, postop_stbuf=0x7fd331391800, xdata=0x0) at changelog.c:1202
#3  0x00007fd33859acef in ctr_setattr_cbk (frame=0x7fd3280028ac, cookie=0x7fd32800222c, this=0x7fd33400b8f0, op_ret=0, op_errno=0, 
    preop_stbuf=0x7fd331391870, postop_stbuf=0x7fd331391800, xdata=0x0) at changetimerecorder.c:451
#4  0x00007fd338dddc30 in posix_setattr (frame=0x7fd32800222c, this=0x7fd334007820, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at posix.c:449
#5  0x00007fd3435c51a0 in default_setattr (frame=0x7fd32800222c, this=0x7fd334009f50, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at defaults.c:2107
#6  0x00007fd33859b2d4 in ctr_setattr (frame=0x7fd3280028ac, this=0x7fd33400b8f0, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at changetimerecorder.c:484
#7  0x00007fd333de9e2d in changelog_setattr (frame=0x7fd32800169c, this=0x7fd33400ee20, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at changelog.c:1239
#8  0x00007fd3435c51a0 in default_setattr (frame=0x7fd32800169c, this=0x7fd3340109b0, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at defaults.c:2107
#9  0x00007fd3339c1a97 in posix_acl_setattr (frame=0x7fd328000d9c, this=0x7fd334011fc0, loc=0x7fd32c007d7c, buf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at posix-acl.c:1784
#10 0x00007fd3435c51a0 in default_setattr (frame=0x7fd328000d9c, this=0x7fd334013400, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at defaults.c:2107
#11 0x00007fd33358623d in up_setattr (frame=0x7fd328000bac, this=0x7fd334014810, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, xdata=0x0)
    at upcall.c:368
#12 0x00007fd3435c238b in default_setattr_resume (frame=0x7fd32c00290c, this=0x7fd334015da0, loc=0x7fd32c007d7c, stbuf=0x7fd32c0082b4, valid=1, 
    xdata=0x0) at defaults.c:1662
#13 0x00007fd3435e2870 in call_resume_wind (stub=0x7fd32c007d3c) at call-stub.c:2252
#14 0x00007fd3435ea7fa in call_resume (stub=0x7fd32c007d3c) at call-stub.c:2571
#15 0x00007fd33337a317 in iot_worker (data=0x7fd334042260) at io-threads.c:210
#16 0x000000315c8079d1 in start_thread () from /lib64/libpthread.so.0
#17 0x000000315c0e886d in clone () from /lib64/libc.so.6

From the bt it is clear that crash is happened in access-control translator's posix_setattr_cbk().

It seems to context of access_control_translator contains invalid entries.
(gdb) p ctx
$1 = (struct posix_acl_ctx *) 0x7fd328003640
(gdb) p *ctx
$2 = {uid = 0, gid = 0, perm = 32768, acl_access = 0x7fd328001850, acl_default = 0x0}
(gdb) p *ctx->acl_access 
$3 = {refcnt = -1379869184, count = 8377310, entries = 0x7fd328001850}

The crash happened when it tried to access invalid memory.