linux/net/sunrpc
Trond Myklebust beb0f0a9fb kernel panic when mount NFSv4
On Tue, 2010-12-14 at 16:58 +0800, Mi Jinlong wrote:
> Hi,
>
> When testing NFSv4 at RHEL6 with kernel 2.6.32, I got a kernel panic
> at NFS client's __rpc_create_common function.
>
> The panic place is:
>   rpc_mkpipe
>     __rpc_lookup_create()          <=== find pipefile *idmap*
>     __rpc_mkpipe()                 <=== pipefile is *idmap*
>       __rpc_create_common()
>        ******  BUG_ON(!d_unhashed(dentry)); ******    *panic*
>
> It means that the dentry's d_flags have be set DCACHE_UNHASHED,
> but it should not be set here.
>
> Is someone known this bug? or give me some idea?
>
> A reproduce program is append, but it can't reproduce the bug every time.
> the export is: "/nfsroot       *(rw,no_root_squash,fsid=0,insecure)"
>
> And the panic message is append.
>
> ============================================================================
> #!/bin/sh
>
> LOOPTOTAL=768
> LOOPCOUNT=0
> ret=0
>
> while [ $LOOPCOUNT -ne $LOOPTOTAL ]
> do
> 	((LOOPCOUNT += 1))
> 	service nfs restart
> 	/usr/sbin/rpc.idmapd
> 	mount -t nfs4 127.0.0.1:/ /mnt|| return 1;
> 	ls -l /var/lib/nfs/rpc_pipefs/nfs/*/
> 	umount /mnt
> 	echo $LOOPCOUNT
> done
>
> ===============================================================================
> Code: af 60 01 00 00 89 fa 89 f0 e8 64 cf 89 f0 e8 5c 7c 64 cf 31 c0 8b 5c 24 10 8b
> 74 24 14 8b 7c 24 18 8b 6c 24 1c 83 c4 20 c3 <0f> 0b eb fc 8b 46 28 c7 44 24 08 20
> de ee f0 c7 44 24 04 56 ea
> EIP:[<f0ee92ea>] __rpc_create_common+0x8a/0xc0 [sunrpc] SS:ESP 0068:eccb5d28
> ---[ end trace 8f5606cd08928ed2]---
> Kernel panic - not syncing: Fatal exception
> Pid:7131, comm: mount.nfs4 Tainted: G     D   -------------------2.6.32 #1
> Call Trace:
>  [<c080ad18>] ? panic+0x42/0xed
>  [<c080e42c>] ? oops_end+0xbc/0xd0
>  [<c040b090>] ? do_invalid_op+0x0/0x90
>  [<c040b10f>] ? do_invalid_op+0x7f/0x90
>  [<f0ee92ea>] ? __rpc_create_common+0x8a/0xc0[sunrpc]
>  [<f0edc433>] ? rpc_free_task+0x33/0x70[sunrpc]
>  [<f0ed6508>] ? prc_call_sync+0x48/0x60[sunrpc]
>  [<f0ed656e>] ? rpc_ping+0x4e/0x60[sunrpc]
>  [<f0ed6eaf>] ? rpc_create+0x38f/0x4f0[sunrpc]
>  [<c080d80b>] ? error_code+0x73/0x78
>  [<f0ee92ea>] ? __rpc_create_common+0x8a/0xc0[sunrpc]
>  [<c0532bda>] ? d_lookup+0x2a/0x40
>  [<f0ee94b1>] ? rpc_mkpipe+0x111/0x1b0[sunrpc]
>  [<f10a59f4>] ? nfs_create_rpc_client+0xb4/0xf0[nfs]
>  [<f10d6c6d>] ? nfs_fscache_get_client_cookie+0x1d/0x50[nfs]
>  [<f10d3fcb>] ? nfs_idmap_new+0x7b/0x140[nfs]
>  [<c05e76aa>] ? strlcpy+0x3a/0x60
>  [<f10a60ca>] ? nfs4_set_client+0xea/0x2b0[nfs]
>  [<f10a6d0c>] ? nfs4_create_server+0xac/0x1b0[nfs]
>  [<c04f1400>] ? krealloc+0x40/0x50
>  [<f10b0e8b>] ? nfs4_remote_get_sb+0x6b/0x250[nfs]
>  [<c04f14ec>] ? kstrdup+0x3c/0x60
>  [<c0520739>] ? vfs_kern_mount+0x69/0x170
>  [<f10b1a3c>] ? nfs_do_root_mount+0x6c/0xa0[nfs]
>  [<f10b1b47>] ? nfs4_try_mount+0x37/0xa0[nfs]
>  [<f10afe6d>] ? nfs4_validate_text_mount_data+-x7d/0xf0[nfs]
>  [<f10b1c42>] ? nfs4_get_sb+0x92/0x2f0
>  [<c0520739>] ? vfs_kern_mount+0x69/0x170
>  [<c05366d2>] ? get_fs_type+0x32/0xb0
>  [<c052089f>] ? do_kern_mount+0x3f/0xe0
>  [<c053954f>] ? do_mount+0x2ef/0x740
>  [<c0537740>] ? copy_mount_options+0xb0/0x120
>  [<c0539a0e>] ? sys_mount+0x6e/0xa0

Hi,

Does the following patch fix the problem?

Cheers
  Trond

--------------------------
SUNRPC: Fix a BUG in __rpc_create_common

From: Trond Myklebust <Trond.Myklebust@netapp.com>

Mi Jinlong reports:

When testing NFSv4 at RHEL6 with kernel 2.6.32, I got a kernel panic
at NFS client's __rpc_create_common function.

The panic place is:
  rpc_mkpipe
      __rpc_lookup_create()          <=== find pipefile *idmap*
      __rpc_mkpipe()                 <=== pipefile is *idmap*
        __rpc_create_common()
         ******  BUG_ON(!d_unhashed(dentry)); ****** *panic*

The test is wrong: we can find ourselves with a hashed negative dentry here
if the idmapper tried to look up the file before we got round to creating
it.

Just replace the BUG_ON() with a d_drop(dentry).

Reported-by: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2011-01-04 13:10:38 -05:00
..
auth_gss SUNRPC: New xdr_streams XDR decoder API 2010-12-16 12:37:25 -05:00
xprtrdma sunrpc/xprtrdma: clean up workqueue usage 2010-10-21 10:11:45 -04:00
addr.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
auth_generic.c sunrpc: fix up rpcauth_remove_module section mismatch 2010-09-29 12:27:37 -04:00
auth_null.c SUNRPC: Move the bound cred to struct rpc_rqst 2010-08-04 08:54:09 -04:00
auth_unix.c SUNRPC: Move the bound cred to struct rpc_rqst 2010-08-04 08:54:09 -04:00
auth.c SUNRPC: New xdr_streams XDR decoder API 2010-12-16 12:37:25 -05:00
backchannel_rqst.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
bc_svc.c Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-04-11 14:53:53 -07:00
cache.c Merge branch 'for-2.6.37' of git://linux-nfs.org/~bfields/linux 2010-10-26 09:55:25 -07:00
clnt.c net/sunrpc/clnt.c: Convert sprintf_symbol to %ps 2010-12-21 11:51:26 -05:00
Kconfig nfsd4: remove spkm3 2010-10-01 18:09:55 -04:00
Makefile SUNRPC: Provide functions for managing universal addresses 2009-08-09 15:09:34 -04:00
netns.h sunrpc: Make the ip_map_cache be per-net 2010-09-27 10:16:12 -04:00
rpc_pipe.c kernel panic when mount NFSv4 2011-01-04 13:10:38 -05:00
rpcb_clnt.c SUNRPC: New xdr_streams XDR decoder API 2010-12-16 12:37:25 -05:00
sched.c Merge branch 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6 2010-10-25 13:48:29 -07:00
socklib.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
stats.c SUNRPC: Simplify rpc_alloc_iostats by removing pointless local variable 2010-11-16 11:58:51 -05:00
sunrpc_syms.c sunrpc: Make the ip_map_cache be per-net 2010-09-27 10:16:12 -04:00
sunrpc.h nfsd41: sunrpc: Added rpc server-side backchannel handling 2009-09-11 15:04:16 -04:00
svc_xprt.c sunrpc: prevent use-after-free on clearing XPT_BUSY 2010-12-07 20:39:55 -05:00
svc.c sunrpc: close connection when a request is irretrievably lost. 2010-09-21 16:57:49 -04:00
svcauth_unix.c sunrpc: Use helper to set v4 mapped addr in ip_map_parse 2010-10-11 20:00:17 -04:00
svcauth.c net: Move && and || to end of previous line 2009-11-29 16:55:45 -08:00
svcsock.c svcrpc: svc_tcp_sendto XPT_DEAD check is redundant 2010-10-25 17:59:34 -04:00
sysctl.c sysctl: Drop & in front of every proc_handler. 2009-11-18 08:37:40 -08:00
timer.c SUNRPC: Add documenting comments in net/sunrpc/timer.c 2009-08-09 15:09:47 -04:00
xdr.c SUNRPC: Add a helper function xdr_inline_peek 2010-10-23 15:27:32 -04:00
xprt.c sunrpc: Turn list_for_each-s into the ..._entry-s 2010-10-19 10:48:16 -04:00
xprtsock.c Merge branch 'for-2.6.37' of git://linux-nfs.org/~bfields/linux 2010-10-26 09:55:25 -07:00