From: Jackie Liu <liuyun01@kylinos.cn> mainline inclusion from mainline-5.4-rc1 commit a1041c27b64ce744632147e19701c95fed14fab1 category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA --------------------------- 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 <liuyun01@kylinos.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: yangerkun <yangerkun@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- fs/io_uring.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6b2295fcb355..3eeee5a03fc8 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2363,12 +2363,15 @@ 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); @@ -2550,12 +2553,15 @@ 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; -- 2.25.1