From a1041c27b64ce744632147e19701c95fed14fab1 Mon Sep 17 00:00:00 2001 From: Jackie Liu Date: Wed, 18 Sep 2019 17:25:52 +0800 Subject: [PATCH] io_uring: fix potential crash issue due to io_get_req failure Sometimes io_get_req will return a NUL, then we need to do the correct error handling, otherwise it will cause the kernel null pointer exception. Fixes: 4fe2c963154c ("io_uring: add support for link with drain") Signed-off-by: Jackie Liu Signed-off-by: Jens Axboe --- fs/io_uring.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index f9139f5bd158..854dedd885fa 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2364,12 +2364,15 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes, if (link && (sqes[i].sqe->flags & IOSQE_IO_DRAIN)) { if (!shadow_req) { shadow_req = io_get_req(ctx, NULL); + if (unlikely(!shadow_req)) + goto out; shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN); refcount_dec(&shadow_req->refs); } shadow_req->sequence = sqes[i].sequence; } +out: if (unlikely(mm_fault)) { io_cqring_add_event(ctx, sqes[i].sqe->user_data, -EFAULT); @@ -2551,12 +2554,15 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit, if (link && (s.sqe->flags & IOSQE_IO_DRAIN)) { if (!shadow_req) { shadow_req = io_get_req(ctx, NULL); + if (unlikely(!shadow_req)) + goto out; shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN); refcount_dec(&shadow_req->refs); } shadow_req->sequence = s.sequence; } +out: s.has_user = true; s.needs_lock = false; s.needs_fixed_file = false; -- 2.11.0