[3.13.y.z extended stable] Patch "NFSD: Call ->set_acl with a NULL ACL structure if no entries" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Tue Jun 17 21:42:15 UTC 2014


This is a note to let you know that I have just added a patch titled

    NFSD: Call ->set_acl with a NULL ACL structure if no entries

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 22b27c5a75e5ffa2c48ebcfaa973f54d96a6135c Mon Sep 17 00:00:00 2001
From: Kinglong Mee <kinglongmee at gmail.com>
Date: Fri, 18 Apr 2014 20:49:04 +0800
Subject: NFSD: Call ->set_acl with a NULL ACL structure if no entries

commit aa07c713ecfc0522916f3cd57ac628ea6127c0ec upstream.

After setting ACL for directory, I got two problems that caused
by the cached zero-length default posix acl.

This patch make sure nfsd4_set_nfs4_acl calls ->set_acl
with a NULL ACL structure if there are no entries.

Thanks for Christoph Hellwig's advice.

First problem:
............ hang ...........

Second problem:
[ 1610.167668] ------------[ cut here ]------------
[ 1610.168320] kernel BUG at /root/nfs/linux/fs/nfsd/nfs4acl.c:239!
[ 1610.168320] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 1610.168320] Modules linked in: nfsv4(OE) nfs(OE) nfsd(OE)
rpcsec_gss_krb5 fscache ip6t_rpfilter ip6t_REJECT cfg80211 xt_conntrack
rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables
ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6
ip6table_mangle ip6table_security ip6table_raw ip6table_filter
ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4
nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw
auth_rpcgss nfs_acl snd_intel8x0 ppdev lockd snd_ac97_codec ac97_bus
snd_pcm snd_timer e1000 pcspkr parport_pc snd parport serio_raw joydev
i2c_piix4 sunrpc(OE) microcode soundcore i2c_core ata_generic pata_acpi
[last unloaded: nfsd]
[ 1610.168320] CPU: 0 PID: 27397 Comm: nfsd Tainted: G           OE
3.15.0-rc1+ #15
[ 1610.168320] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 12/01/2006
[ 1610.168320] task: ffff88005ab653d0 ti: ffff88005a944000 task.ti:
ffff88005a944000
[ 1610.168320] RIP: 0010:[<ffffffffa034d5ed>]  [<ffffffffa034d5ed>]
_posix_to_nfsv4_one+0x3cd/0x3d0 [nfsd]
[ 1610.168320] RSP: 0018:ffff88005a945b00  EFLAGS: 00010293
[ 1610.168320] RAX: 0000000000000001 RBX: ffff88006700bac0 RCX:
0000000000000000
[ 1610.168320] RDX: 0000000000000000 RSI: ffff880067c83f00 RDI:
ffff880068233300
[ 1610.168320] RBP: ffff88005a945b48 R08: ffffffff81c64830 R09:
0000000000000000
[ 1610.168320] R10: ffff88004ea85be0 R11: 000000000000f475 R12:
ffff880068233300
[ 1610.168320] R13: 0000000000000003 R14: 0000000000000002 R15:
ffff880068233300
[ 1610.168320] FS:  0000000000000000(0000) GS:ffff880077800000(0000)
knlGS:0000000000000000
[ 1610.168320] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1610.168320] CR2: 00007f5bcbd3b0b9 CR3: 0000000001c0f000 CR4:
00000000000006f0
[ 1610.168320] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 1610.168320] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[ 1610.168320] Stack:
[ 1610.168320]  ffffffff00000000 0000000b67c83500 000000076700bac0
0000000000000000
[ 1610.168320]  ffff88006700bac0 ffff880068233300 ffff88005a945c08
0000000000000002
[ 1610.168320]  0000000000000000 ffff88005a945b88 ffffffffa034e2d5
000000065a945b68
[ 1610.168320] Call Trace:
[ 1610.168320]  [<ffffffffa034e2d5>] nfsd4_get_nfs4_acl+0x95/0x150 [nfsd]
[ 1610.168320]  [<ffffffffa03400d6>] nfsd4_encode_fattr+0x646/0x1e70 [nfsd]
[ 1610.168320]  [<ffffffff816a6e6e>] ? kmemleak_alloc+0x4e/0xb0
[ 1610.168320]  [<ffffffffa0327962>] ?
nfsd_setuser_and_check_port+0x52/0x80 [nfsd]
[ 1610.168320]  [<ffffffff812cd4bb>] ? selinux_cred_prepare+0x1b/0x30
[ 1610.168320]  [<ffffffffa0341caa>] nfsd4_encode_getattr+0x5a/0x60 [nfsd]
[ 1610.168320]  [<ffffffffa0341e07>] nfsd4_encode_operation+0x67/0x110
[nfsd]
[ 1610.168320]  [<ffffffffa033844d>] nfsd4_proc_compound+0x21d/0x810 [nfsd]
[ 1610.168320]  [<ffffffffa0324d9b>] nfsd_dispatch+0xbb/0x200 [nfsd]
[ 1610.168320]  [<ffffffffa00850cd>] svc_process_common+0x46d/0x6d0 [sunrpc]
[ 1610.168320]  [<ffffffffa0085433>] svc_process+0x103/0x170 [sunrpc]
[ 1610.168320]  [<ffffffffa032472f>] nfsd+0xbf/0x130 [nfsd]
[ 1610.168320]  [<ffffffffa0324670>] ? nfsd_destroy+0x80/0x80 [nfsd]
[ 1610.168320]  [<ffffffff810a5202>] kthread+0xd2/0xf0
[ 1610.168320]  [<ffffffff810a5130>] ? insert_kthread_work+0x40/0x40
[ 1610.168320]  [<ffffffff816c1ebc>] ret_from_fork+0x7c/0xb0
[ 1610.168320]  [<ffffffff810a5130>] ? insert_kthread_work+0x40/0x40
[ 1610.168320] Code: 78 02 e9 e7 fc ff ff 31 c0 31 d2 31 c9 66 89 45 ce
41 8b 04 24 66 89 55 d0 66 89 4d d2 48 8d 04 80 49 8d 5c 84 04 e9 37 fd
ff ff <0f> 0b 90 0f 1f 44 00 00 55 8b 56 08 c7 07 00 00 00 00 8b 46 0c
[ 1610.168320] RIP  [<ffffffffa034d5ed>] _posix_to_nfsv4_one+0x3cd/0x3d0
[nfsd]
[ 1610.168320]  RSP <ffff88005a945b00>
[ 1610.257313] ---[ end trace 838254e3e352285b ]---

Signed-off-by: Kinglong Mee <kinglongmee at gmail.com>
Signed-off-by: J. Bruce Fields <bfields at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/nfsd/nfs4acl.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/fs/nfsd/nfs4acl.c b/fs/nfsd/nfs4acl.c
index 8a50b3c..e15bcbd 100644
--- a/fs/nfsd/nfs4acl.c
+++ b/fs/nfsd/nfs4acl.c
@@ -385,8 +385,10 @@ sort_pacl(struct posix_acl *pacl)
 	 * by uid/gid. */
 	int i, j;

-	if (pacl->a_count <= 4)
-		return; /* no users or groups */
+	/* no users or groups */
+	if (!pacl || pacl->a_count <= 4)
+		return;
+
 	i = 1;
 	while (pacl->a_entries[i].e_tag == ACL_USER)
 		i++;
@@ -513,13 +515,12 @@ posix_state_to_acl(struct posix_acl_state *state, unsigned int flags)

 	/*
 	 * ACLs with no ACEs are treated differently in the inheritable
-	 * and effective cases: when there are no inheritable ACEs, we
-	 * set a zero-length default posix acl:
+	 * and effective cases: when there are no inheritable ACEs,
+	 * calls ->set_acl with a NULL ACL structure.
 	 */
-	if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT)) {
-		pacl = posix_acl_alloc(0, GFP_KERNEL);
-		return pacl ? pacl : ERR_PTR(-ENOMEM);
-	}
+	if (state->empty && (flags & NFS4_ACL_TYPE_DEFAULT))
+		return NULL;
+
 	/*
 	 * When there are no effective ACEs, the following will end
 	 * up setting a 3-element effective posix ACL with all
--
1.9.1





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