Jeff Layton b3ecba0967 sunrpc: fix sleeping under rcu_read_lock in gss_stringify_acceptor ... Bruce reported that he was seeing the following BUG pop: BUG: sleeping function called from invalid context at mm/slab.c:2846 in_atomic(): 0, irqs_disabled(): 0, pid: 4539, name: mount.nfs 2 locks held by mount.nfs/4539: #0: (nfs_clid_init_mutex){+.+.+.}, at: [<ffffffffa01c0a9a>] nfs4_discover_server_trunking+0x4a/0x2f0 [nfsv4] #1: (rcu_read_lock){......}, at: [<ffffffffa00e3185>] gss_stringify_acceptor+0x5/0xb0 [auth_rpcgss] Preemption disabled at:[<ffffffff81a4f082>] printk+0x4d/0x4f CPU: 3 PID: 4539 Comm: mount.nfs Not tainted 3.18.0-rc1-00013-g5b095e9 #3393 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 ffff880021499390 ffff8800381476a8 ffffffff81a534cf 0000000000000001 0000000000000000 ffff8800381476c8 ffffffff81097854 00000000000000d0 0000000000000018 ffff880038147718 ffffffff8118e4f3 0000000020479f00 Call Trace: [<ffffffff81a534cf>] dump_stack+0x4f/0x7c [<ffffffff81097854>] __might_sleep+0x114/0x180 [<ffffffff8118e4f3>] __kmalloc+0x1a3/0x280 [<ffffffffa00e31d8>] gss_stringify_acceptor+0x58/0xb0 [auth_rpcgss] [<ffffffffa00e3185>] ? gss_stringify_acceptor+0x5/0xb0 [auth_rpcgss] [<ffffffffa006b438>] rpcauth_stringify_acceptor+0x18/0x30 [sunrpc] [<ffffffffa01b0469>] nfs4_proc_setclientid+0x199/0x380 [nfsv4] [<ffffffffa01b04d0>] ? nfs4_proc_setclientid+0x200/0x380 [nfsv4] [<ffffffffa01bdf1a>] nfs40_discover_server_trunking+0xda/0x150 [nfsv4] [<ffffffffa01bde45>] ? nfs40_discover_server_trunking+0x5/0x150 [nfsv4] [<ffffffffa01c0acf>] nfs4_discover_server_trunking+0x7f/0x2f0 [nfsv4] [<ffffffffa01c8e24>] nfs4_init_client+0x104/0x2f0 [nfsv4] [<ffffffffa01539b4>] nfs_get_client+0x314/0x3f0 [nfs] [<ffffffffa0153780>] ? nfs_get_client+0xe0/0x3f0 [nfs] [<ffffffffa01c83aa>] nfs4_set_client+0x8a/0x110 [nfsv4] [<ffffffffa0069708>] ? __rpc_init_priority_wait_queue+0xa8/0xf0 [sunrpc] [<ffffffffa01c9b2f>] nfs4_create_server+0x12f/0x390 [nfsv4] [<ffffffffa01c1472>] nfs4_remote_mount+0x32/0x60 [nfsv4] [<ffffffff81196489>] mount_fs+0x39/0x1b0 [<ffffffff81166145>] ? __alloc_percpu+0x15/0x20 [<ffffffff811b276b>] vfs_kern_mount+0x6b/0x150 [<ffffffffa01c1396>] nfs_do_root_mount+0x86/0xc0 [nfsv4] [<ffffffffa01c1784>] nfs4_try_mount+0x44/0xc0 [nfsv4] [<ffffffffa01549b7>] ? get_nfs_version+0x27/0x90 [nfs] [<ffffffffa0161a2d>] nfs_fs_mount+0x47d/0xd60 [nfs] [<ffffffff81a59c5e>] ? mutex_unlock+0xe/0x10 [<ffffffffa01606a0>] ? nfs_remount+0x430/0x430 [nfs] [<ffffffffa01609c0>] ? nfs_clone_super+0x140/0x140 [nfs] [<ffffffff81196489>] mount_fs+0x39/0x1b0 [<ffffffff81166145>] ? __alloc_percpu+0x15/0x20 [<ffffffff811b276b>] vfs_kern_mount+0x6b/0x150 [<ffffffff811b5830>] do_mount+0x210/0xbe0 [<ffffffff811b54ca>] ? copy_mount_options+0x3a/0x160 [<ffffffff811b651f>] SyS_mount+0x6f/0xb0 [<ffffffff81a5c852>] system_call_fastpath+0x12/0x17 Sleeping under the rcu_read_lock is bad. This patch fixes it by dropping the rcu_read_lock before doing the allocation and then reacquiring it and redoing the dereference before doing the copy. If we find that the string has somehow grown in the meantime, we'll reallocate and try again. Cc: <stable@vger.kernel.org> # v3.17+ Reported-by: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>		2014-11-13 13:15:49 -05:00
..
auth_gss	sunrpc: fix sleeping under rcu_read_lock in gss_stringify_acceptor	2014-11-13 13:15:49 -05:00
xprtrdma	Merge branch 'for-3.18' of git://linux-nfs.org/~bfields/linux	2014-10-08 12:51:44 -04:00
Kconfig	xprtrdma: add separate Kconfig options for NFSoRDMA client and server support	2014-03-28 18:02:12 -04:00
Makefile	xprtrdma: add separate Kconfig options for NFSoRDMA client and server support	2014-03-28 18:02:12 -04:00
addr.c	replace strict_strto calls	2014-07-12 18:45:49 -04:00
auth.c	SUNRPC: remove all refcounting of groupinfo from rpcauth_lookupcred	2014-08-04 09:22:08 -04:00
auth_generic.c	sunrpc/auth: allow lockless (rcu) lookup of credential cache.	2014-08-03 17:14:12 -04:00
auth_null.c	sunrpc/auth: allow lockless (rcu) lookup of credential cache.	2014-08-03 17:14:12 -04:00
auth_unix.c	SUNRPC refactor rpcauth_checkverf error returns	2013-09-03 15:25:09 -04:00
backchannel_rqst.c	arch: Mass conversion of smp_mb__*()	2014-04-18 14:20:48 +02:00
bc_svc.c	SUNRPC: remove BUG_ON from bc_send	2012-11-04 14:43:41 -05:00
cache.c	SUNRPC: Fix printk that is not only for nfsd	2014-05-08 14:59:51 -04:00
clnt.c	Merge branch 'bugfixes' into linux-next	2014-09-30 17:21:41 -04:00
netns.h	Merge branch 'for-3.14' of git://linux-nfs.org/~bfields/linux	2014-01-30 10:18:43 -08:00
rpc_pipe.c	rpc_pipe: Drop memory allocation cast	2014-07-12 18:43:44 -04:00
rpcb_clnt.c	SUNRPC: If the rpcbind channel is disconnected, fail the call to unregister	2013-08-07 17:07:18 -04:00
sched.c	NFS/SUNRPC: Remove other deadlock-avoidance mechanisms in nfs_release_page()	2014-09-25 08:25:47 -04:00
socklib.c	net: Save software checksum complete	2014-06-11 15:46:13 -07:00
stats.c	SUNRPC: Deprecate rpc_client->cl_protname	2013-08-30 09:19:34 -04:00
sunrpc.h	SUNRPC: track whether a request is coming from a loop-back interface.	2014-05-22 15:59:18 -04:00
sunrpc_syms.c	sunrpc: create a new dummy pipe for gssd to hold open	2013-12-06 13:06:30 -05:00
svc.c	SUNRPC: get rid of the request wait queue	2014-08-17 12:00:11 -04:00
svc_xprt.c	SUNRPC: Fix compile on non-x86	2014-08-28 15:51:35 -04:00
svcauth.c	nfsd4: better reservation of head space for krb5	2014-05-30 17:32:17 -04:00
svcauth_unix.c	svcrpc: fix failures to handle -1 uid's	2013-07-08 17:27:23 -04:00
svcsock.c	sunrpc: fix byte-swapping of displayed XID	2014-08-28 16:00:07 -04:00
sysctl.c	net: Convert uses of typedef ctl_table to struct ctl_table	2013-06-13 02:36:09 -07:00
timer.c	net: cleanup unsigned to unsigned int	2012-04-15 12:44:40 -04:00
xdr.c	SUNRPC: xdr_get_next_encode_buffer should be declared static	2014-07-18 11:35:46 -04:00
xprt.c	NFS client updates for Linux 3.17	2014-08-13 18:13:19 -06:00
xprtsock.c	NFS/SUNRPC: Remove other deadlock-avoidance mechanisms in nfs_release_page()	2014-09-25 08:25:47 -04:00