The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4ed734b0d0913e566a9d871e15d24eb240f269f7 Mon Sep 17 00:00:00 2001

From: Jens Axboe axboe@kernel.dk Date: Fri, 20 Mar 2020 11:23:41 -0600 Subject: [PATCH] io_uring: honor original task RLIMIT_FSIZE

With the previous fixes for number of files open checking, I added some debug code to see if we had other spots where we're checking rlimit() against the async io-wq workers. The only one I found was file size checking, which we should also honor.

During write and fallocate prep, store the max file size and override that for the current ask if we're in io-wq worker context.

Cc: stable@vger.kernel.org # 5.1+ Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/fs/io_uring.c b/fs/io_uring.c index dfe40bf80adc..05260ed485ad 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -604,7 +604,10 @@ struct io_kiocb { struct list_head list; unsigned int flags; refcount_t refs; - struct task_struct *task; + union { + struct task_struct *task; + unsigned long fsize; + }; u64 user_data; u32 result; u32 sequence; @@ -2593,6 +2596,8 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, if (unlikely(!(req->file->f_mode & FMODE_WRITE))) return -EBADF;

+ req->fsize = rlimit(RLIMIT_FSIZE); + /* either don't need iovec imported or already have it */ if (!req->io || req->flags & REQ_F_NEED_CLEANUP) return 0; @@ -2662,10 +2667,17 @@ static int io_write(struct io_kiocb *req, bool force_nonblock) } kiocb->ki_flags |= IOCB_WRITE;

+ if (!force_nonblock) + current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize; + if (req->file->f_op->write_iter) ret2 = call_write_iter(req->file, kiocb, &iter); else ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter); + + if (!force_nonblock) + current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; + /* * Raw bdev writes will -EOPNOTSUPP for IOCB_NOWAIT. Just * retry them without IOCB_NOWAIT. @@ -2848,8 +2860,10 @@ static void __io_fallocate(struct io_kiocb *req) { int ret;

+ current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize; ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off, req->sync.len); + current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); @@ -2875,6 +2889,7 @@ static int io_fallocate_prep(struct io_kiocb *req, req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->addr); req->sync.mode = READ_ONCE(sqe->len); + req->fsize = rlimit(RLIMIT_FSIZE); return 0; }