From: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
BUG: KASAN: use-after-free in __wake_up_common+0x637/0x650
Read of size 8 at addr ffff8880304250d8 by task iou-wrk-28796/28802
Call Trace:
__dump_stack [inline]
dump_stack+0x141/0x1d7
print_address_description.constprop.0.cold+0x5b/0x2c6
__kasan_report [inline]
kasan_report.cold+0x7c/0xd8
__wake_up_common+0x637/0x650
__wake_up_common_lock+0xd0/0x130
io_worker_handle_work+0x9dd/0x1790
io_wqe_worker+0xb2a/0xd40
ret_from_fork+0x1f/0x30
Allocated by task 28798:
kzalloc_node [inline]
io_wq_create+0x3c4/0xdd0
io_init_wq_offload [inline]
io_uring_alloc_task_context+0x1bf/0x6b0
__io_uring_add_task_file+0x29a/0x3c0
io_uring_add_task_file [inline]
io_uring_install_fd [inline]
io_uring_create [inline]
io_uring_setup+0x209a/0x2bd0
do_syscall_64+0x3a/0xb0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 28798:
kfree+0x106/0x2c0
io_wq_destroy+0x182/0x380
io_wq_put [inline]
io_wq_put_and_exit+0x7a/0xa0
io_uring_clean_tctx [inline]
__io_uring_cancel+0x428/0x530
io_uring_files_cancel
do_exit+0x299/0x2a60
do_group_exit+0x125/0x310
get_signal+0x47f/0x2150
arch_do_signal_or_restart+0x2a8/0x1eb0
handle_signal_work[inline]
exit_to_user_mode_loop [inline]
exit_to_user_mode_prepare+0x171/0x280
__syscall_exit_to_user_mode_work [inline]
syscall_exit_to_user_mode+0x19/0x60
do_syscall_64+0x47/0xb0
entry_SYSCALL_64_after_hwframe
There are the following scenarios, hash waitqueue is shared by
io-wq1 and io-wq2. (note: wqe is worker)
io-wq1:worker2 | locks bit1
io-wq2:worker1 | waits bit1
io-wq1:worker3 | waits bit1
io-wq1:worker2 | completes all wqe bit1 work items
io-wq1:worker2 | drop bit1, exit
io-wq2:worker1 | locks bit1
io-wq1:worker3 | can not locks bit1, waits bit1 and exit
io-wq1 | exit and free io-wq1
io-wq2:worker1 | drops bit1
io-wq1:worker3 | be waked up, even though wqe is freed
After all iou-wrk belonging to io-wq1 have exited, remove wqe
form hash waitqueue, it is guaranteed that there will be no more
wqe belonging to io-wq1 in the hash waitqueue.
Reported-by: syzbot+6cb11ade52aa17095297@xxxxxxxxxxxxxxxxxxxxxxxxx
Suggested-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Zqiang <qiang.zhang@xxxxxxxxxxxxx>
---
v1->v2:
Modify commit information
fs/io-wq.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 5361a9b4b47b..911a1274aabd 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -1003,13 +1003,16 @@ static void io_wq_exit_workers(struct io_wq *wq)
struct io_wqe *wqe = wq->wqes[node];
io_wq_for_each_worker(wqe, io_wq_worker_wake, NULL);
- spin_lock_irq(&wq->hash->wait.lock);
- list_del_init(&wq->wqes[node]->wait.entry);
- spin_unlock_irq(&wq->hash->wait.lock);
}
rcu_read_unlock();
io_worker_ref_put(wq);
wait_for_completion(&wq->worker_done);
+
+ for_each_node(node) {
+ spin_lock_irq(&wq->hash->wait.lock);
+ list_del_init(&wq->wqes[node]->wait.entry);
+ spin_unlock_irq(&wq->hash->wait.lock);
+ }
put_task_struct(wq->task);
wq->task = NULL;
}
--
2.17.1
