On 14 Nov 2016, at 11:50, Benjamin Coddington wrote:
While walking the list of lock_states, keep the current
nfs4_lock_state
referenced so that it isn't freed while checking.
Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 7897826d7c51..9a1cb9e8c4fc 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2564,12 +2564,15 @@ static void
nfs41_check_delegation_stateid(struct nfs4_state *state)
static int nfs41_check_expired_locks(struct nfs4_state *state)
{
int status, ret = NFS_OK;
- struct nfs4_lock_state *lsp;
+ struct nfs4_lock_state *lsp, *tmp;
struct nfs_server *server = NFS_SERVER(state->inode);
if (!test_bit(LK_STATE_IN_USE, &state->flags))
goto out;
- list_for_each_entry(lsp, &state->lock_states, ls_locks) {
+ spin_lock(&state->state_lock);
+ list_for_each_entry_safe(lsp, tmp, &state->lock_states, ls_locks) {
+ atomic_inc(&lsp->ls_count);
+ spin_unlock(&state->state_lock);
if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags)) {
struct rpc_cred *cred = lsp->ls_state->owner->so_cred;
@@ -2588,7 +2591,10 @@ static int nfs41_check_expired_locks(struct
nfs4_state *state)
break;
}
}
- };
+ nfs4_put_lock_state(lsp);
+ spin_lock(&state->state_lock);
+ }
+ spin_unlock(&state->state_lock);
out:
return ret;
}
Actually, something else may be wrong here.. after several more hours of
testing with this and Trond's two fixes for CLOSE races this popped up:
[ 8102.015071] BUG: unable to handle kernel NULL pointer dereference at
0000000000000048
[ 8102.015985] IP: [<ffffffff8182717c>] _raw_spin_lock+0xc/0x30
[ 8102.016622] PGD 0
[ 8102.016829]
[ 8102.017014] Oops: 0002 [#1] SMP
[ 8102.017357] Modules linked in: nfsv4 dns_resolver nfs ip6t_rpfilter
ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat
ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6
nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_raw
ip6table_security iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4
nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_raw
iptable_security ebtable_filter ebtables ip6table_filter ip6_tables nfsd
auth_rpcgss nfs_acl lockd grace sunrpc virtio_balloon virtio_console
virtio_net virtio_blk crct10dif_pclmul ppdev crc32_pclmul crc32c_intel
ghash_clmulni_intel virtio_pci serio_raw i2c_piix4 virtio_ring virtio
ata_generic parport_pc pata_acpi parport acpi_cpufreq tpm_tis
tpm_tis_core tpm
[ 8102.025180] CPU: 3 PID: 4475 Comm: ::1-manager Not tainted
4.9.0-rc5-00268-gbb3ec452d27c #45
[ 8102.026093] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.8.1-20150318_183358- 04/01/2014
[ 8102.027122] task: ffff880132b93a80 task.stack: ffffc90003200000
[ 8102.027769] RIP: 0010:[<ffffffff8182717c>] [<ffffffff8182717c>]
_raw_spin_lock+0xc/0x30
[ 8102.028657] RSP: 0018:ffffc90003203d40 EFLAGS: 00010246
[ 8102.029227] RAX: 0000000000000000 RBX: ffff880132d9c31c RCX:
0000000000000001
[ 8102.029996] RDX: 0000000000000001 RSI: 0000000000000048 RDI:
0000000000000048
[ 8102.030771] RBP: ffffc90003203d58 R08: 0000000032b45601 R09:
000000018010000e
[ 8102.031532] R10: 000000008010000e R11: 0000000000100000 R12:
0000000000000048
[ 8102.032291] R13: 0000000000000000 R14: 0000000000000000 R15:
ffff880139fc2050
[ 8102.033064] FS: 0000000000000000(0000) GS:ffff88013fd80000(0000)
knlGS:0000000000000000
[ 8102.033930] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8102.034546] CR2: 0000000000000048 CR3: 0000000139678000 CR4:
00000000000406e0
[ 8102.035312] Stack:
[ 8102.035542] ffffffff81489818 ffff880132d9c200 0000000000000000
ffffc90003203d78
[ 8102.036400] ffffffffa02f9289 ffff8801314f29c0 0000000000000000
ffffc90003203de8
[ 8102.037259] ffffffffa02e3dd2 ffff88013393f000 ffff8801314f29e0
ffff8801314f2a08
[ 8102.038120] Call Trace:
[ 8102.038392] [<ffffffff81489818>] ? _atomic_dec_and_lock+0x48/0x5b
[ 8102.039073] [<ffffffffa02f9289>] nfs4_put_lock_state+0x29/0x90
[nfsv4]
[ 8102.039797] [<ffffffffa02e3dd2>] nfs41_open_expired+0x192/0x410
[nfsv4]
[ 8102.040523] [<ffffffffa02f859f>] nfs4_do_reclaim+0x1af/0x630 [nfsv4]
[ 8102.041227] [<ffffffffa02f8f30>] nfs4_run_state_manager+0x510/0x7d0
[nfsv4]
[ 8102.041995] [<ffffffffa02f8a20>] ? nfs4_do_reclaim+0x630/0x630
[nfsv4]
[ 8102.042719] [<ffffffffa02f8a20>] ? nfs4_do_reclaim+0x630/0x630
[nfsv4]
[ 8102.043434] [<ffffffff810c96a9>] kthread+0xd9/0xf0
[ 8102.043968] [<ffffffff810c95d0>] ? kthread_park+0x60/0x60
[ 8102.044559] [<ffffffff81827615>] ret_from_fork+0x25/0x30
[ 8102.045150] Code: c0 ba 01 00 00 00 f0 0f b1 17 85 c0 75 02 5d c3 89
c6 e8 18 db 8c ff 5d c3 66 0f 1f 44 00 00 66 66 66 66 90 31 c0 ba 01 00
00 00 <f0> 0f b1 17 85 c0 75 01 c3 55 89 c6 48 89 e5 e8 f0 da 8c ff 5d
[ 8102.048136] RIP [<ffffffff8182717c>] _raw_spin_lock+0xc/0x30
[ 8102.048775] RSP <ffffc90003203d40>
[ 8102.049153] CR2: 0000000000000048
[ 8102.049893] ---[ end trace 8dc47952e274960a ]---
[ 8102.050391] Kernel panic - not syncing: Fatal exception
[ 8102.051090] Kernel Offset: disabled
[ 8102.051475] ---[ end Kernel panic - not syncing: Fatal exception
OK, it now looks like the nfs4_state has been freed while walking the
list of
lock_states. I'll have to look at this a bit more tomorrow. I have to
ferry
the kids around now.
Ben
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