diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index f4ddb9d23241..b35300e4c9a7 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2929,11 +2929,23 @@ SYSCALL_DEFINE2(io_uring_setup, u32, entries, static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, void __user *arg, unsigned nr_args) + __releases(ctx->uring_lock) + __acquires(ctx->uring_lock) { int ret; percpu_ref_kill(&ctx->refs); + + /* + * Drop uring mutex before waiting for references to exit. If another + * thread is currently inside io_uring_enter() it might need to grab + * the uring_lock to make progress. If we hold it here across the drain + * wait, then we can deadlock. It's safe to drop the mutex here, since + * no new references will come in after we've killed the percpu ref. + */ + mutex_unlock(&ctx->uring_lock); wait_for_completion(&ctx->ctx_done); + mutex_lock(&ctx->uring_lock); switch (opcode) { case IORING_REGISTER_BUFFERS: |