mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Peilin Ye](/assets/img/avatar_default.png)
Currently @audit_context is allocated twice for io_uring workers:
1. copy_process() calls audit_alloc();
2. io_sq_thread() or io_wqe_worker() calls audit_alloc_kernel() (which
is effectively audit_alloc()) and overwrites @audit_context,
causing:
BUG: memory leak
unreferenced object 0xffff888144547400 (size 1024):
<...>
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff8135cfc3>] audit_alloc+0x133/0x210
[<ffffffff81239e63>] copy_process+0xcd3/0x2340
[<ffffffff8123b5f3>] create_io_thread+0x63/0x90
[<ffffffff81686604>] create_io_worker+0xb4/0x230
[<ffffffff81686f68>] io_wqe_enqueue+0x248/0x3b0
[<ffffffff8167663a>] io_queue_iowq+0xba/0x200
[<ffffffff816768b3>] io_queue_async+0x113/0x180
[<ffffffff816840df>] io_req_task_submit+0x18f/0x1a0
[<ffffffff816841cd>] io_apoll_task_func+0xdd/0x120
[<ffffffff8167d49f>] tctx_task_work+0x11f/0x570
[<ffffffff81272c4e>] task_work_run+0x7e/0xc0
[<ffffffff8125a688>] get_signal+0xc18/0xf10
[<ffffffff8111645b>] arch_do_signal_or_restart+0x2b/0x730
[<ffffffff812ea44e>] exit_to_user_mode_prepare+0x5e/0x180
[<ffffffff844ae1b2>] syscall_exit_to_user_mode+0x12/0x20
[<ffffffff844a7e80>] do_syscall_64+0x40/0x80
Then,
3. io_sq_thread() or io_wqe_worker() frees @audit_context using
audit_free();
4. do_exit() eventually calls audit_free() again, which is okay
because audit_free() does a NULL check.
As suggested by Paul Moore, fix it by deleting audit_alloc_kernel() and
redundant audit_free() calls.
Fixes: 5bd2182d58
("audit,io_uring,io-wq: add some basic audit support to io_uring")
Suggested-by: Paul Moore <paul@paul-moore.com>
Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220803222343.31673-1-yepeilin.cs@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
421 lines
9.5 KiB
C
421 lines
9.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Contains the core associated with submission side polling of the SQ
|
|
* ring, offloading submissions from the application to a kernel thread.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/file.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/audit.h>
|
|
#include <linux/security.h>
|
|
#include <linux/io_uring.h>
|
|
|
|
#include <uapi/linux/io_uring.h>
|
|
|
|
#include "io_uring.h"
|
|
#include "sqpoll.h"
|
|
|
|
#define IORING_SQPOLL_CAP_ENTRIES_VALUE 8
|
|
|
|
enum {
|
|
IO_SQ_THREAD_SHOULD_STOP = 0,
|
|
IO_SQ_THREAD_SHOULD_PARK,
|
|
};
|
|
|
|
void io_sq_thread_unpark(struct io_sq_data *sqd)
|
|
__releases(&sqd->lock)
|
|
{
|
|
WARN_ON_ONCE(sqd->thread == current);
|
|
|
|
/*
|
|
* Do the dance but not conditional clear_bit() because it'd race with
|
|
* other threads incrementing park_pending and setting the bit.
|
|
*/
|
|
clear_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
|
|
if (atomic_dec_return(&sqd->park_pending))
|
|
set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
|
|
mutex_unlock(&sqd->lock);
|
|
}
|
|
|
|
void io_sq_thread_park(struct io_sq_data *sqd)
|
|
__acquires(&sqd->lock)
|
|
{
|
|
WARN_ON_ONCE(sqd->thread == current);
|
|
|
|
atomic_inc(&sqd->park_pending);
|
|
set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state);
|
|
mutex_lock(&sqd->lock);
|
|
if (sqd->thread)
|
|
wake_up_process(sqd->thread);
|
|
}
|
|
|
|
void io_sq_thread_stop(struct io_sq_data *sqd)
|
|
{
|
|
WARN_ON_ONCE(sqd->thread == current);
|
|
WARN_ON_ONCE(test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state));
|
|
|
|
set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
|
|
mutex_lock(&sqd->lock);
|
|
if (sqd->thread)
|
|
wake_up_process(sqd->thread);
|
|
mutex_unlock(&sqd->lock);
|
|
wait_for_completion(&sqd->exited);
|
|
}
|
|
|
|
void io_put_sq_data(struct io_sq_data *sqd)
|
|
{
|
|
if (refcount_dec_and_test(&sqd->refs)) {
|
|
WARN_ON_ONCE(atomic_read(&sqd->park_pending));
|
|
|
|
io_sq_thread_stop(sqd);
|
|
kfree(sqd);
|
|
}
|
|
}
|
|
|
|
static __cold void io_sqd_update_thread_idle(struct io_sq_data *sqd)
|
|
{
|
|
struct io_ring_ctx *ctx;
|
|
unsigned sq_thread_idle = 0;
|
|
|
|
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
|
|
sq_thread_idle = max(sq_thread_idle, ctx->sq_thread_idle);
|
|
sqd->sq_thread_idle = sq_thread_idle;
|
|
}
|
|
|
|
void io_sq_thread_finish(struct io_ring_ctx *ctx)
|
|
{
|
|
struct io_sq_data *sqd = ctx->sq_data;
|
|
|
|
if (sqd) {
|
|
io_sq_thread_park(sqd);
|
|
list_del_init(&ctx->sqd_list);
|
|
io_sqd_update_thread_idle(sqd);
|
|
io_sq_thread_unpark(sqd);
|
|
|
|
io_put_sq_data(sqd);
|
|
ctx->sq_data = NULL;
|
|
}
|
|
}
|
|
|
|
static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
|
|
{
|
|
struct io_ring_ctx *ctx_attach;
|
|
struct io_sq_data *sqd;
|
|
struct fd f;
|
|
|
|
f = fdget(p->wq_fd);
|
|
if (!f.file)
|
|
return ERR_PTR(-ENXIO);
|
|
if (!io_is_uring_fops(f.file)) {
|
|
fdput(f);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
ctx_attach = f.file->private_data;
|
|
sqd = ctx_attach->sq_data;
|
|
if (!sqd) {
|
|
fdput(f);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
if (sqd->task_tgid != current->tgid) {
|
|
fdput(f);
|
|
return ERR_PTR(-EPERM);
|
|
}
|
|
|
|
refcount_inc(&sqd->refs);
|
|
fdput(f);
|
|
return sqd;
|
|
}
|
|
|
|
static struct io_sq_data *io_get_sq_data(struct io_uring_params *p,
|
|
bool *attached)
|
|
{
|
|
struct io_sq_data *sqd;
|
|
|
|
*attached = false;
|
|
if (p->flags & IORING_SETUP_ATTACH_WQ) {
|
|
sqd = io_attach_sq_data(p);
|
|
if (!IS_ERR(sqd)) {
|
|
*attached = true;
|
|
return sqd;
|
|
}
|
|
/* fall through for EPERM case, setup new sqd/task */
|
|
if (PTR_ERR(sqd) != -EPERM)
|
|
return sqd;
|
|
}
|
|
|
|
sqd = kzalloc(sizeof(*sqd), GFP_KERNEL);
|
|
if (!sqd)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
atomic_set(&sqd->park_pending, 0);
|
|
refcount_set(&sqd->refs, 1);
|
|
INIT_LIST_HEAD(&sqd->ctx_list);
|
|
mutex_init(&sqd->lock);
|
|
init_waitqueue_head(&sqd->wait);
|
|
init_completion(&sqd->exited);
|
|
return sqd;
|
|
}
|
|
|
|
static inline bool io_sqd_events_pending(struct io_sq_data *sqd)
|
|
{
|
|
return READ_ONCE(sqd->state);
|
|
}
|
|
|
|
static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
|
|
{
|
|
unsigned int to_submit;
|
|
int ret = 0;
|
|
|
|
to_submit = io_sqring_entries(ctx);
|
|
/* if we're handling multiple rings, cap submit size for fairness */
|
|
if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE)
|
|
to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE;
|
|
|
|
if (!wq_list_empty(&ctx->iopoll_list) || to_submit) {
|
|
const struct cred *creds = NULL;
|
|
|
|
if (ctx->sq_creds != current_cred())
|
|
creds = override_creds(ctx->sq_creds);
|
|
|
|
mutex_lock(&ctx->uring_lock);
|
|
if (!wq_list_empty(&ctx->iopoll_list))
|
|
io_do_iopoll(ctx, true);
|
|
|
|
/*
|
|
* Don't submit if refs are dying, good for io_uring_register(),
|
|
* but also it is relied upon by io_ring_exit_work()
|
|
*/
|
|
if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)) &&
|
|
!(ctx->flags & IORING_SETUP_R_DISABLED))
|
|
ret = io_submit_sqes(ctx, to_submit);
|
|
mutex_unlock(&ctx->uring_lock);
|
|
|
|
if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait))
|
|
wake_up(&ctx->sqo_sq_wait);
|
|
if (creds)
|
|
revert_creds(creds);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool io_sqd_handle_event(struct io_sq_data *sqd)
|
|
{
|
|
bool did_sig = false;
|
|
struct ksignal ksig;
|
|
|
|
if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) ||
|
|
signal_pending(current)) {
|
|
mutex_unlock(&sqd->lock);
|
|
if (signal_pending(current))
|
|
did_sig = get_signal(&ksig);
|
|
cond_resched();
|
|
mutex_lock(&sqd->lock);
|
|
}
|
|
return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
|
|
}
|
|
|
|
static int io_sq_thread(void *data)
|
|
{
|
|
struct io_sq_data *sqd = data;
|
|
struct io_ring_ctx *ctx;
|
|
unsigned long timeout = 0;
|
|
char buf[TASK_COMM_LEN];
|
|
DEFINE_WAIT(wait);
|
|
|
|
snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
|
|
set_task_comm(current, buf);
|
|
|
|
if (sqd->sq_cpu != -1)
|
|
set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu));
|
|
else
|
|
set_cpus_allowed_ptr(current, cpu_online_mask);
|
|
current->flags |= PF_NO_SETAFFINITY;
|
|
|
|
mutex_lock(&sqd->lock);
|
|
while (1) {
|
|
bool cap_entries, sqt_spin = false;
|
|
|
|
if (io_sqd_events_pending(sqd) || signal_pending(current)) {
|
|
if (io_sqd_handle_event(sqd))
|
|
break;
|
|
timeout = jiffies + sqd->sq_thread_idle;
|
|
}
|
|
|
|
cap_entries = !list_is_singular(&sqd->ctx_list);
|
|
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
|
|
int ret = __io_sq_thread(ctx, cap_entries);
|
|
|
|
if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list)))
|
|
sqt_spin = true;
|
|
}
|
|
if (io_run_task_work())
|
|
sqt_spin = true;
|
|
|
|
if (sqt_spin || !time_after(jiffies, timeout)) {
|
|
cond_resched();
|
|
if (sqt_spin)
|
|
timeout = jiffies + sqd->sq_thread_idle;
|
|
continue;
|
|
}
|
|
|
|
prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE);
|
|
if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) {
|
|
bool needs_sched = true;
|
|
|
|
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
|
|
atomic_or(IORING_SQ_NEED_WAKEUP,
|
|
&ctx->rings->sq_flags);
|
|
if ((ctx->flags & IORING_SETUP_IOPOLL) &&
|
|
!wq_list_empty(&ctx->iopoll_list)) {
|
|
needs_sched = false;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Ensure the store of the wakeup flag is not
|
|
* reordered with the load of the SQ tail
|
|
*/
|
|
smp_mb__after_atomic();
|
|
|
|
if (io_sqring_entries(ctx)) {
|
|
needs_sched = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (needs_sched) {
|
|
mutex_unlock(&sqd->lock);
|
|
schedule();
|
|
mutex_lock(&sqd->lock);
|
|
}
|
|
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
|
|
atomic_andnot(IORING_SQ_NEED_WAKEUP,
|
|
&ctx->rings->sq_flags);
|
|
}
|
|
|
|
finish_wait(&sqd->wait, &wait);
|
|
timeout = jiffies + sqd->sq_thread_idle;
|
|
}
|
|
|
|
io_uring_cancel_generic(true, sqd);
|
|
sqd->thread = NULL;
|
|
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
|
|
atomic_or(IORING_SQ_NEED_WAKEUP, &ctx->rings->sq_flags);
|
|
io_run_task_work();
|
|
mutex_unlock(&sqd->lock);
|
|
|
|
complete(&sqd->exited);
|
|
do_exit(0);
|
|
}
|
|
|
|
int io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
|
|
do {
|
|
if (!io_sqring_full(ctx))
|
|
break;
|
|
prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
|
|
|
|
if (!io_sqring_full(ctx))
|
|
break;
|
|
schedule();
|
|
} while (!signal_pending(current));
|
|
|
|
finish_wait(&ctx->sqo_sq_wait, &wait);
|
|
return 0;
|
|
}
|
|
|
|
__cold int io_sq_offload_create(struct io_ring_ctx *ctx,
|
|
struct io_uring_params *p)
|
|
{
|
|
int ret;
|
|
|
|
/* Retain compatibility with failing for an invalid attach attempt */
|
|
if ((ctx->flags & (IORING_SETUP_ATTACH_WQ | IORING_SETUP_SQPOLL)) ==
|
|
IORING_SETUP_ATTACH_WQ) {
|
|
struct fd f;
|
|
|
|
f = fdget(p->wq_fd);
|
|
if (!f.file)
|
|
return -ENXIO;
|
|
if (!io_is_uring_fops(f.file)) {
|
|
fdput(f);
|
|
return -EINVAL;
|
|
}
|
|
fdput(f);
|
|
}
|
|
if (ctx->flags & IORING_SETUP_SQPOLL) {
|
|
struct task_struct *tsk;
|
|
struct io_sq_data *sqd;
|
|
bool attached;
|
|
|
|
ret = security_uring_sqpoll();
|
|
if (ret)
|
|
return ret;
|
|
|
|
sqd = io_get_sq_data(p, &attached);
|
|
if (IS_ERR(sqd)) {
|
|
ret = PTR_ERR(sqd);
|
|
goto err;
|
|
}
|
|
|
|
ctx->sq_creds = get_current_cred();
|
|
ctx->sq_data = sqd;
|
|
ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
|
|
if (!ctx->sq_thread_idle)
|
|
ctx->sq_thread_idle = HZ;
|
|
|
|
io_sq_thread_park(sqd);
|
|
list_add(&ctx->sqd_list, &sqd->ctx_list);
|
|
io_sqd_update_thread_idle(sqd);
|
|
/* don't attach to a dying SQPOLL thread, would be racy */
|
|
ret = (attached && !sqd->thread) ? -ENXIO : 0;
|
|
io_sq_thread_unpark(sqd);
|
|
|
|
if (ret < 0)
|
|
goto err;
|
|
if (attached)
|
|
return 0;
|
|
|
|
if (p->flags & IORING_SETUP_SQ_AFF) {
|
|
int cpu = p->sq_thread_cpu;
|
|
|
|
ret = -EINVAL;
|
|
if (cpu >= nr_cpu_ids || !cpu_online(cpu))
|
|
goto err_sqpoll;
|
|
sqd->sq_cpu = cpu;
|
|
} else {
|
|
sqd->sq_cpu = -1;
|
|
}
|
|
|
|
sqd->task_pid = current->pid;
|
|
sqd->task_tgid = current->tgid;
|
|
tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
|
|
if (IS_ERR(tsk)) {
|
|
ret = PTR_ERR(tsk);
|
|
goto err_sqpoll;
|
|
}
|
|
|
|
sqd->thread = tsk;
|
|
ret = io_uring_alloc_task_context(tsk, ctx);
|
|
wake_up_new_task(tsk);
|
|
if (ret)
|
|
goto err;
|
|
} else if (p->flags & IORING_SETUP_SQ_AFF) {
|
|
/* Can't have SQ_AFF without SQPOLL */
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
return 0;
|
|
err_sqpoll:
|
|
complete(&ctx->sq_data->exited);
|
|
err:
|
|
io_sq_thread_finish(ctx);
|
|
return ret;
|
|
}
|