This patch fixes a bug, which is triggered by following code:
while (1) {
if (umount2("/", MNT_DETACH) ||
setns(fd, CLONE_NEWNS))
return break;
}
[ 260.548301] ------------[ cut here ]------------
[ 260.550941] kernel BUG at /build/buildd/linux-3.13.0/fs/pnode.c:372!
[ 260.552068] invalid opcode: 0000 [#1] SMP
[ 260.552068] Modules linked in: xt_CHECKSUM iptable_mangle xt_tcpudp xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc dm_thin_pool dm_persistent_data dm_bufio dm_bio_prison iptable_filter ip_tables x_tables crct10dif_pclmul crc32_pclmul ghash_clmulni_intel binfmt_misc nfsd auth_rpcgss nfs_acl aesni_intel nfs lockd aes_x86_64 sunrpc fscache lrw gf128mul glue_helper ablk_helper cryptd serio_raw ppdev parport_pc lp parport btrfs xor raid6_pq libcrc32c psmouse floppy
[ 260.552068] CPU: 0 PID: 1723 Comm: nsenter Not tainted 3.13.0-30-generic #55-Ubuntu
[ 260.552068] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 260.552068] task: ffff8800376097f0 ti: ffff880074824000 task.ti: ffff880074824000
[ 260.552068] RIP: 0010:[<ffffffff811e9483>] [<ffffffff811e9483>] propagate_umount+0x123/0x130
[ 260.552068] RSP: 0018:ffff880074825e98 EFLAGS: 00010246
[ 260.552068] RAX: ffff88007c741140 RBX: 0000000000000002 RCX: ffff88007c741190
[ 260.552068] RDX: ffff88007c741190 RSI: ffff880074825ec0 RDI: ffff880074825ec0
[ 260.552068] RBP: ffff880074825eb0 R08: 00000000000172e0 R09: ffff88007fc172e0
[ 260.552068] R10: ffffffff811cc642 R11: ffffea0001d59000 R12: ffff88007c741140
[ 260.552068] R13: ffff88007c741140 R14: ffff88007c741140 R15: 0000000000000000
[ 260.552068] FS: 00007fd5c7e41740(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000
[ 260.552068] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 260.552068] CR2: 00007fd5c7968050 CR3: 0000000070124000 CR4: 00000000000406f0
[ 260.552068] Stack:
[ 260.552068] 0000000000000002 0000000000000002 ffff88007c631000 ffff880074825ed8
[ 260.552068] ffffffff811dcfac ffff88007c741140 0000000000000002 ffff88007c741160
[ 260.552068] ffff880074825f38 ffffffff811dd12b ffffffff811cc642 0000000075640000
[ 260.552068] Call Trace:
[ 260.552068] [<ffffffff811dcfac>] umount_tree+0x20c/0x260
[ 260.552068] [<ffffffff811dd12b>] do_umount+0x12b/0x300
[ 260.552068] [<ffffffff811cc642>] ? final_putname+0x22/0x50
[ 260.552068] [<ffffffff811cc849>] ? putname+0x29/0x40
[ 260.552068] [<ffffffff811dd88c>] SyS_umount+0xdc/0x100
[ 260.552068] [<ffffffff8172aeff>] tracesys+0xe1/0xe6
[ 260.552068] Code: 89 50 08 48 8b 50 08 48 89 02 49 89 45 08 e9 72 ff ff ff 0f 1f 44 00 00 4c 89 e6 4c 89 e7 e8 f5 f6 ff ff 48 89 c3 e9 39 ff ff ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 90 66 66 66 66 90 55 b8 01
[ 260.552068] RIP [<ffffffff811e9483>] propagate_umount+0x123/0x130
[ 260.552068] RSP <ffff880074825e98>
[ 260.611451] ---[ end trace 11c33d85f1d4c652 ]--
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
---
fs/namespace.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/namespace.c b/fs/namespace.c
index f50a848..a63e0a9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1363,6 +1363,9 @@ static int do_umount(struct mount *mnt, int flags)
return retval;
}
+ if (!mnt_has_parent(mnt))
+ return -EINVAL;
+
namespace_lock();
lock_mount_hash();
event++;
--
1.9.3
--
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