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| author |   Peilin Ye <peilin.ye@bytedance.com> | 2022-08-03 15:23:43 -0700 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2022-08-04 08:33:54 -0600 |
| commit | f482aa98652795846cc55da98ebe331eb74f3d0b (patch) | |
| tree | 6cb094583f2ef7c0d9d5bfeab129145e0fa07cd2 /io_uring | |
| parent | io_uring: pass correct parameters to io_req_set_res (diff) | |
| download | linux-dev-f482aa98652795846cc55da98ebe331eb74f3d0b.tar.xz linux-dev-f482aa98652795846cc55da98ebe331eb74f3d0b.zip | |
audit, io_uring, io-wq: Fix memory leak in io_sq_thread() and io_wqe_worker()
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: 5bd2182d58e9 ("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>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io-wq.c | 3 | ||||
| -rw-r--r-- | io_uring/sqpoll.c | 4 |
2 files changed, 0 insertions, 7 deletions
diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c index 77df5b43bf52..c6536d4b2da0 100644 --- a/io_uring/io-wq.c +++ b/io_uring/io-wq.c @@ -624,8 +624,6 @@ static int io_wqe_worker(void *data) snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task->pid); set_task_comm(current, buf); - audit_alloc_kernel(current); - while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { long ret; @@ -660,7 +658,6 @@ static int io_wqe_worker(void *data) if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) io_worker_handle_work(worker); - audit_free(current); io_worker_exit(worker); return 0; } diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c index 76d4d70c733a..559652380672 100644 --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -235,8 +235,6 @@ static int io_sq_thread(void *data) set_cpus_allowed_ptr(current, cpu_online_mask); current->flags |= PF_NO_SETAFFINITY; - audit_alloc_kernel(current); - mutex_lock(&sqd->lock); while (1) { bool cap_entries, sqt_spin = false; @@ -310,8 +308,6 @@ static int io_sq_thread(void *data) io_run_task_work(); mutex_unlock(&sqd->lock); - audit_free(current); - complete(&sqd->exited); do_exit(0); } |