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c840b8e1f0
Move holding the RCU from nfs_to_nfsd_file_put_local to
nfs_to_nfsd_net_put. It is the call to nfs_to->nfsd_serv_put that
requires the RCU anyway (the puts for nfsd_file and netns were
combined to avoid an extra indirect reference but that
micro-optimization isn't possible now).
This fixes xfstests generic/013 and it triggering:
"Voluntary context switch within RCU read-side critical section!"
[ 143.545738] Call Trace:
[ 143.546206] <TASK>
[ 143.546625] ? show_regs+0x6d/0x80
[ 143.547267] ? __warn+0x91/0x140
[ 143.547951] ? rcu_note_context_switch+0x496/0x5d0
[ 143.548856] ? report_bug+0x193/0x1a0
[ 143.549557] ? handle_bug+0x63/0xa0
[ 143.550214] ? exc_invalid_op+0x1d/0x80
[ 143.550938] ? asm_exc_invalid_op+0x1f/0x30
[ 143.551736] ? rcu_note_context_switch+0x496/0x5d0
[ 143.552634] ? wakeup_preempt+0x62/0x70
[ 143.553358] __schedule+0xaa/0x1380
[ 143.554025] ? _raw_spin_unlock_irqrestore+0x12/0x40
[ 143.554958] ? try_to_wake_up+0x1fe/0x6b0
[ 143.555715] ? wake_up_process+0x19/0x20
[ 143.556452] schedule+0x2e/0x120
[ 143.557066] schedule_preempt_disabled+0x19/0x30
[ 143.557933] rwsem_down_read_slowpath+0x24d/0x4a0
[ 143.558818] ? xfs_efi_item_format+0x50/0xc0 [xfs]
[ 143.559894] down_read+0x4e/0xb0
[ 143.560519] xlog_cil_commit+0x1b2/0xbc0 [xfs]
[ 143.561460] ? _raw_spin_unlock+0x12/0x30
[ 143.562212] ? xfs_inode_item_precommit+0xc7/0x220 [xfs]
[ 143.563309] ? xfs_trans_run_precommits+0x69/0xd0 [xfs]
[ 143.564394] __xfs_trans_commit+0xb5/0x330 [xfs]
[ 143.565367] xfs_trans_roll+0x48/0xc0 [xfs]
[ 143.566262] xfs_defer_trans_roll+0x57/0x100 [xfs]
[ 143.567278] xfs_defer_finish_noroll+0x27a/0x490 [xfs]
[ 143.568342] xfs_defer_finish+0x1a/0x80 [xfs]
[ 143.569267] xfs_bunmapi_range+0x4d/0xb0 [xfs]
[ 143.570208] xfs_itruncate_extents_flags+0x13d/0x230 [xfs]
[ 143.571353] xfs_free_eofblocks+0x12e/0x190 [xfs]
[ 143.572359] xfs_file_release+0x12d/0x140 [xfs]
[ 143.573324] __fput+0xe8/0x2d0
[ 143.573922] __fput_sync+0x1d/0x30
[ 143.574574] nfsd_filp_close+0x33/0x60 [nfsd]
[ 143.575430] nfsd_file_free+0x96/0x150 [nfsd]
[ 143.576274] nfsd_file_put+0xf7/0x1a0 [nfsd]
[ 143.577104] nfsd_file_put_local+0x18/0x30 [nfsd]
[ 143.578070] nfs_close_local_fh+0x101/0x110 [nfs_localio]
[ 143.579079] __put_nfs_open_context+0xc9/0x180 [nfs]
[ 143.580031] nfs_file_clear_open_context+0x4a/0x60 [nfs]
[ 143.581038] nfs_file_release+0x3e/0x60 [nfs]
[ 143.581879] __fput+0xe8/0x2d0
[ 143.582464] __fput_sync+0x1d/0x30
[ 143.583108] __x64_sys_close+0x41/0x80
[ 143.583823] x64_sys_call+0x189a/0x20d0
[ 143.584552] do_syscall_64+0x64/0x170
[ 143.585240] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 143.586185] RIP: 0033:0x7f3c5153efd7
Fixes: 65f2a5c366 ("nfs_common: fix race in NFS calls to nfsd_file_put_local() and nfsd_serv_put()")
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
103 lines
2.9 KiB
C
103 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2024 Mike Snitzer <snitzer@hammerspace.com>
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* Copyright (C) 2024 NeilBrown <neilb@suse.de>
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*/
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#ifndef __LINUX_NFSLOCALIO_H
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#define __LINUX_NFSLOCALIO_H
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/* nfsd_file structure is purposely kept opaque to NFS client */
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struct nfsd_file;
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#if IS_ENABLED(CONFIG_NFS_LOCALIO)
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#include <linux/module.h>
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#include <linux/list.h>
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#include <linux/uuid.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/svcauth.h>
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#include <linux/nfs.h>
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#include <net/net_namespace.h>
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/*
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* Useful to allow a client to negotiate if localio
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* possible with its server.
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*
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* See Documentation/filesystems/nfs/localio.rst for more detail.
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*/
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typedef struct {
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uuid_t uuid;
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struct list_head list;
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struct net __rcu *net; /* nfsd's network namespace */
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struct auth_domain *dom; /* auth_domain for localio */
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} nfs_uuid_t;
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void nfs_uuid_init(nfs_uuid_t *);
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bool nfs_uuid_begin(nfs_uuid_t *);
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void nfs_uuid_end(nfs_uuid_t *);
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void nfs_uuid_is_local(const uuid_t *, struct list_head *,
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struct net *, struct auth_domain *, struct module *);
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void nfs_uuid_invalidate_clients(struct list_head *list);
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void nfs_uuid_invalidate_one_client(nfs_uuid_t *nfs_uuid);
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/* localio needs to map filehandle -> struct nfsd_file */
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extern struct nfsd_file *
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nfsd_open_local_fh(struct net *, struct auth_domain *, struct rpc_clnt *,
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const struct cred *, const struct nfs_fh *,
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const fmode_t) __must_hold(rcu);
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struct nfsd_localio_operations {
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bool (*nfsd_serv_try_get)(struct net *);
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void (*nfsd_serv_put)(struct net *);
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struct nfsd_file *(*nfsd_open_local_fh)(struct net *,
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struct auth_domain *,
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struct rpc_clnt *,
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const struct cred *,
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const struct nfs_fh *,
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const fmode_t);
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struct net *(*nfsd_file_put_local)(struct nfsd_file *);
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struct file *(*nfsd_file_file)(struct nfsd_file *);
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} ____cacheline_aligned;
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extern void nfsd_localio_ops_init(void);
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extern const struct nfsd_localio_operations *nfs_to;
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struct nfsd_file *nfs_open_local_fh(nfs_uuid_t *,
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struct rpc_clnt *, const struct cred *,
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const struct nfs_fh *, const fmode_t);
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static inline void nfs_to_nfsd_net_put(struct net *net)
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{
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/*
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* Once reference to nfsd_serv is dropped, NFSD could be
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* unloaded, so ensure safe return from nfsd_file_put_local()
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* by always taking RCU.
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*/
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rcu_read_lock();
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nfs_to->nfsd_serv_put(net);
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rcu_read_unlock();
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}
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static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio)
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{
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/*
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* Must not hold RCU otherwise nfsd_file_put() can easily trigger:
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* "Voluntary context switch within RCU read-side critical section!"
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* by scheduling deep in underlying filesystem (e.g. XFS).
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*/
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struct net *net = nfs_to->nfsd_file_put_local(localio);
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nfs_to_nfsd_net_put(net);
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}
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#else /* CONFIG_NFS_LOCALIO */
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static inline void nfsd_localio_ops_init(void)
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{
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}
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static inline void nfs_to_nfsd_file_put_local(struct nfsd_file *localio)
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{
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}
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#endif /* CONFIG_NFS_LOCALIO */
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#endif /* __LINUX_NFSLOCALIO_H */
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