Revision ff1fa2081d173b01cebe2fbf0a2d0f1cee9ce4b5 authored by Jakub Kicinski on 29 June 2022, 18:19:10 UTC, committed by Jakub Kicinski on 30 June 2022, 18:34:10 UTC
Eric reports that syzbot made short work out of my speculative fix. Indeed when queue gets detached its tfile->tun remains, so we would try to stop NAPI twice with a detach(), close() sequence. Alternative fix would be to move tun_napi_disable() to tun_detach_all() and let the NAPI run after the queue has been detached. Fixes: a8fc8cb5692a ("net: tun: stop NAPI when detaching queues") Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220629181911.372047-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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fs_operation.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* Fileserver-directed operation handling.
*
* Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "internal.h"
static atomic_t afs_operation_debug_counter;
/*
* Create an operation against a volume.
*/
struct afs_operation *afs_alloc_operation(struct key *key, struct afs_volume *volume)
{
struct afs_operation *op;
_enter("");
op = kzalloc(sizeof(*op), GFP_KERNEL);
if (!op)
return ERR_PTR(-ENOMEM);
if (!key) {
key = afs_request_key(volume->cell);
if (IS_ERR(key)) {
kfree(op);
return ERR_CAST(key);
}
} else {
key_get(key);
}
op->key = key;
op->volume = afs_get_volume(volume, afs_volume_trace_get_new_op);
op->net = volume->cell->net;
op->cb_v_break = volume->cb_v_break;
op->debug_id = atomic_inc_return(&afs_operation_debug_counter);
op->error = -EDESTADDRREQ;
op->ac.error = SHRT_MAX;
_leave(" = [op=%08x]", op->debug_id);
return op;
}
/*
* Lock the vnode(s) being operated upon.
*/
static bool afs_get_io_locks(struct afs_operation *op)
{
struct afs_vnode *vnode = op->file[0].vnode;
struct afs_vnode *vnode2 = op->file[1].vnode;
_enter("");
if (op->flags & AFS_OPERATION_UNINTR) {
mutex_lock(&vnode->io_lock);
op->flags |= AFS_OPERATION_LOCK_0;
_leave(" = t [1]");
return true;
}
if (!vnode2 || !op->file[1].need_io_lock || vnode == vnode2)
vnode2 = NULL;
if (vnode2 > vnode)
swap(vnode, vnode2);
if (mutex_lock_interruptible(&vnode->io_lock) < 0) {
op->error = -ERESTARTSYS;
op->flags |= AFS_OPERATION_STOP;
_leave(" = f [I 0]");
return false;
}
op->flags |= AFS_OPERATION_LOCK_0;
if (vnode2) {
if (mutex_lock_interruptible_nested(&vnode2->io_lock, 1) < 0) {
op->error = -ERESTARTSYS;
op->flags |= AFS_OPERATION_STOP;
mutex_unlock(&vnode->io_lock);
op->flags &= ~AFS_OPERATION_LOCK_0;
_leave(" = f [I 1]");
return false;
}
op->flags |= AFS_OPERATION_LOCK_1;
}
_leave(" = t [2]");
return true;
}
static void afs_drop_io_locks(struct afs_operation *op)
{
struct afs_vnode *vnode = op->file[0].vnode;
struct afs_vnode *vnode2 = op->file[1].vnode;
_enter("");
if (op->flags & AFS_OPERATION_LOCK_1)
mutex_unlock(&vnode2->io_lock);
if (op->flags & AFS_OPERATION_LOCK_0)
mutex_unlock(&vnode->io_lock);
}
static void afs_prepare_vnode(struct afs_operation *op, struct afs_vnode_param *vp,
unsigned int index)
{
struct afs_vnode *vnode = vp->vnode;
if (vnode) {
vp->fid = vnode->fid;
vp->dv_before = vnode->status.data_version;
vp->cb_break_before = afs_calc_vnode_cb_break(vnode);
if (vnode->lock_state != AFS_VNODE_LOCK_NONE)
op->flags |= AFS_OPERATION_CUR_ONLY;
if (vp->modification)
set_bit(AFS_VNODE_MODIFYING, &vnode->flags);
}
if (vp->fid.vnode)
_debug("PREP[%u] {%llx:%llu.%u}",
index, vp->fid.vid, vp->fid.vnode, vp->fid.unique);
}
/*
* Begin an operation on the fileserver.
*
* Fileserver operations are serialised on the server by vnode, so we serialise
* them here also using the io_lock.
*/
bool afs_begin_vnode_operation(struct afs_operation *op)
{
struct afs_vnode *vnode = op->file[0].vnode;
ASSERT(vnode);
_enter("");
if (op->file[0].need_io_lock)
if (!afs_get_io_locks(op))
return false;
afs_prepare_vnode(op, &op->file[0], 0);
afs_prepare_vnode(op, &op->file[1], 1);
op->cb_v_break = op->volume->cb_v_break;
_leave(" = true");
return true;
}
/*
* Tidy up a filesystem cursor and unlock the vnode.
*/
static void afs_end_vnode_operation(struct afs_operation *op)
{
_enter("");
if (op->error == -EDESTADDRREQ ||
op->error == -EADDRNOTAVAIL ||
op->error == -ENETUNREACH ||
op->error == -EHOSTUNREACH)
afs_dump_edestaddrreq(op);
afs_drop_io_locks(op);
if (op->error == -ECONNABORTED)
op->error = afs_abort_to_error(op->ac.abort_code);
}
/*
* Wait for an in-progress operation to complete.
*/
void afs_wait_for_operation(struct afs_operation *op)
{
_enter("");
while (afs_select_fileserver(op)) {
op->cb_s_break = op->server->cb_s_break;
if (test_bit(AFS_SERVER_FL_IS_YFS, &op->server->flags) &&
op->ops->issue_yfs_rpc)
op->ops->issue_yfs_rpc(op);
else if (op->ops->issue_afs_rpc)
op->ops->issue_afs_rpc(op);
else
op->ac.error = -ENOTSUPP;
if (op->call)
op->error = afs_wait_for_call_to_complete(op->call, &op->ac);
}
switch (op->error) {
case 0:
_debug("success");
op->ops->success(op);
break;
case -ECONNABORTED:
if (op->ops->aborted)
op->ops->aborted(op);
fallthrough;
default:
if (op->ops->failed)
op->ops->failed(op);
break;
}
afs_end_vnode_operation(op);
if (op->error == 0 && op->ops->edit_dir) {
_debug("edit_dir");
op->ops->edit_dir(op);
}
_leave("");
}
/*
* Dispose of an operation.
*/
int afs_put_operation(struct afs_operation *op)
{
int i, ret = op->error;
_enter("op=%08x,%d", op->debug_id, ret);
if (op->ops && op->ops->put)
op->ops->put(op);
if (op->file[0].modification)
clear_bit(AFS_VNODE_MODIFYING, &op->file[0].vnode->flags);
if (op->file[1].modification && op->file[1].vnode != op->file[0].vnode)
clear_bit(AFS_VNODE_MODIFYING, &op->file[1].vnode->flags);
if (op->file[0].put_vnode)
iput(&op->file[0].vnode->netfs.inode);
if (op->file[1].put_vnode)
iput(&op->file[1].vnode->netfs.inode);
if (op->more_files) {
for (i = 0; i < op->nr_files - 2; i++)
if (op->more_files[i].put_vnode)
iput(&op->more_files[i].vnode->netfs.inode);
kfree(op->more_files);
}
afs_end_cursor(&op->ac);
afs_put_serverlist(op->net, op->server_list);
afs_put_volume(op->net, op->volume, afs_volume_trace_put_put_op);
key_put(op->key);
kfree(op);
return ret;
}
int afs_do_sync_operation(struct afs_operation *op)
{
afs_begin_vnode_operation(op);
afs_wait_for_operation(op);
return afs_put_operation(op);
}
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