| Message ID | 20170222124653.GA11726@dustball.brq.redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Jan Stancek <jstancek@redhat.com> wrote: > I'm running into following warning with 4.10 reliably (on ppc64le) > when I mount NFS volume (exported by RHEL6 system): Yeah. I've seen this before. > Patch below makes it go away for me, but I'm not sure it's the correct way. The right solution is to split user_key_payload(). It's actually getting used for two different things. We really need a user_key_payload_rcu() that just uses rcu_dereference(). David -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/nfs/nfs4idmap.c b/fs/nfs/nfs4idmap.c index c444285bb1b1..a67d1c04ba40 100644 --- a/fs/nfs/nfs4idmap.c +++ b/fs/nfs/nfs4idmap.c @@ -309,7 +309,7 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen, goto out; } - rcu_read_lock(); + down_read(&rkey->sem); rkey->perm |= KEY_USR_VIEW; ret = key_validate(rkey); @@ -329,7 +329,7 @@ static ssize_t nfs_idmap_get_key(const char *name, size_t namelen, ret = -EINVAL; out_up: - rcu_read_unlock(); + up_read(&rkey->sem); key_put(rkey); out: return ret;
Hi, I'm running into following warning with 4.10 reliably (on ppc64le) when I mount NFS volume (exported by RHEL6 system): # mount rhel6-nfs:/export/home /mnt/rhel6-nfs # mount rhel6-nfs:/export/home on /mnt/rhel6-nfs type nfs4 (rw,relatime,vers=4.0,rsize=1048576, wsize=1048576,namlen=255,hard,proto=tcp6,port=0,timeo=600,retrans=2,sec=sys, clientaddr=REDACTED,local_lock=none,addr=REDACTED) [ 37.198383] FS-Cache: Loaded [ 37.411783] FS-Cache: Netfs 'nfs' registered for caching [ 37.444264] Key type dns_resolver registered [ 37.701588] NFS: Registering the id_resolver key type [ 37.701669] Key type id_resolver registered [ 37.701692] Key type id_legacy registered [ 38.046889] =============================== [ 38.046912] [ INFO: suspicious RCU usage. ] [ 38.046936] 4.10.0 #1 Tainted: G W [ 38.046965] ------------------------------- [ 38.046988] ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage! [ 38.047030] other info that might help us debug this: [ 38.047074] rcu_scheduler_active = 2, debug_locks = 0 [ 38.047111] 1 lock held by mount.nfs/5987: [ 38.047133] #0: (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4] [ 38.047203] stack backtrace: [ 38.047233] CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G W 4.10.0 #1 [ 38.047276] Call Trace: [ 38.047295] [c0000000fef3ac80] [c000000000a18a08] dump_stack+0xe8/0x154 (unreliable) [ 38.047340] [c0000000fef3acc0] [c000000000159f80] lockdep_rcu_suspicious+0x140/0x190 [ 38.047392] [c0000000fef3ad40] [d000000002527ce0] nfs_idmap_get_key+0x380/0x420 [nfsv4] [ 38.047444] [c0000000fef3adb0] [d0000000025287e0] nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4] [ 38.047496] [c0000000fef3ae30] [d00000000251897c] decode_getfattr_attrs+0xfac/0x16b0 [nfsv4] [ 38.047554] [c0000000fef3af30] [d00000000251913c] decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4] [ 38.047612] [c0000000fef3afe0] [d000000002519b3c] nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4] [ 38.047674] [c0000000fef3b040] [d00000000656d928] rpcauth_unwrap_resp+0xe8/0x140 [sunrpc] [ 38.047725] [c0000000fef3b120] [d0000000065549ac] call_decode+0x29c/0x910 [sunrpc] [ 38.047777] [c0000000fef3b1c0] [d00000000656a370] __rpc_execute+0x140/0x8f0 [sunrpc] [ 38.047828] [c0000000fef3b2d0] [d000000006553420] rpc_run_task+0x170/0x200 [sunrpc] [ 38.047878] [c0000000fef3b330] [d0000000024f0cf8] nfs4_call_sync_sequence+0x68/0xa0 [nfsv4] [ 38.047928] [c0000000fef3b3c0] [d0000000024ff190] _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4] [ 38.047986] [c0000000fef3b490] [d000000002502390] nfs4_lookup_root+0xe0/0x350 [nfsv4] [ 38.048037] [c0000000fef3b550] [d000000002502670] nfs4_lookup_root_sec+0x70/0xa0 [nfsv4] [ 38.048087] [c0000000fef3b5a0] [d000000002502764] nfs4_find_root_sec+0xc4/0x100 [nfsv4] [ 38.048137] [c0000000fef3b5f0] [d000000002508b7c] nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4] [ 38.048189] [c0000000fef3b630] [d00000000252fe0c] nfs4_get_rootfh+0x6c/0x190 [nfsv4] [ 38.048241] [c0000000fef3b720] [d0000000025306a4] nfs4_server_common_setup+0xc4/0x260 [nfsv4] [ 38.048299] [c0000000fef3b7b0] [d000000002532bd8] nfs4_create_server+0x278/0x3c0 [nfsv4] [ 38.048352] [c0000000fef3b870] [d000000002522010] nfs4_remote_mount+0x50/0xb0 [nfsv4] [ 38.048397] [c0000000fef3b8b0] [c000000000377924] mount_fs+0x74/0x210 [ 38.048435] [c0000000fef3b960] [c0000000003a2f68] vfs_kern_mount+0x78/0x220 [ 38.048480] [c0000000fef3b9e0] [d000000002521e90] nfs_do_root_mount+0xb0/0x140 [nfsv4] [ 38.048531] [c0000000fef3ba70] [d000000002522540] nfs4_try_mount+0x60/0x100 [nfsv4] [ 38.048583] [c0000000fef3bb00] [d00000000532adfc] nfs_fs_mount+0x5ec/0xda0 [nfs] [ 38.048627] [c0000000fef3bbd0] [c000000000377924] mount_fs+0x74/0x210 [ 38.048665] [c0000000fef3bc80] [c0000000003a2f68] vfs_kern_mount+0x78/0x220 [ 38.048702] [c0000000fef3bd00] [c0000000003a8a34] do_mount+0x254/0xf70 [ 38.048739] [c0000000fef3bde0] [c0000000003a9b74] SyS_mount+0x94/0x100 [ 38.048777] [c0000000fef3be30] [c00000000000b390] system_call+0x38/0xe0 nfs_idmap_get_key user_key_payload rcu_dereference_key rcu_dereference_protected rcu_dereference_protected comment says: * This function is only for update-side use. Using this function * when protected only by rcu_read_lock() will result in infrequent * but very ugly failures. Patch below makes it go away for me, but I'm not sure it's the correct way. Regards, Jan -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html