After __io_free_req() put a ctx ref, it should assumed that the ctx may already be gone. However, it can be accessed to put back fallback req. Free req first and then put a req. Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- fs/io_uring.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 40996f25822e..013f31e35e78 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1526,12 +1526,15 @@ static void io_dismantle_req(struct io_kiocb *req) static void __io_free_req(struct io_kiocb *req) { + struct io_ring_ctx *ctx; + io_dismantle_req(req); - percpu_ref_put(&req->ctx->refs); + ctx = req->ctx; if (likely(!io_is_fallback_req(req))) kmem_cache_free(req_cachep, req); else - clear_bit_unlock(0, (unsigned long *) &req->ctx->fallback_req); + clear_bit_unlock(0, (unsigned long *) &ctx->fallback_req); + percpu_ref_put(&ctx->refs); } static bool io_link_cancel_timeout(struct io_kiocb *req) -- 2.24.0