Re: FAILED: patch "[PATCH] io_uring: honor original task RLIMIT_FSIZE" failed to apply to 5.4-stable tree

[Jens Axboe <axboe@kernel.dk>]

On 4/14/20 10:31 AM, Jens Axboe wrote:
> On 4/14/20 6:20 AM, gregkh@linuxfoundation.org wrote:
>>
>> 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>.
> 
> Here's a 5.4 backport.

Sorry, please use this one!


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 e37b84146453..2519e57afbca 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -331,6 +331,7 @@ struct io_kiocb {
 #define REQ_F_ISREG		2048	/* regular file */
 #define REQ_F_MUST_PUNT		4096	/* must be punted even for NONBLOCK */
 #define REQ_F_TIMEOUT_NOSEQ	8192	/* no timeout sequence */
+	unsigned long		fsize;
 	u64			user_data;
 	u32			result;
 	u32			sequence;
@@ -1085,6 +1086,9 @@ static int io_prep_rw(struct io_kiocb *req, const struct sqe_submit *s,
 	if (S_ISREG(file_inode(req->file)->i_mode))
 		req->flags |= REQ_F_ISREG;
 
+	if (force_nonblock)
+		req->fsize = rlimit(RLIMIT_FSIZE);
+
 	/*
 	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
 	 * we know to async punt it even if it was opened O_NONBLOCK
@@ -1504,10 +1508,17 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
 		}
 		kiocb->ki_flags |= IOCB_WRITE;
 
+		if (!force_nonblock)
+			current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
+
 		if (file->f_op->write_iter)
 			ret2 = call_write_iter(file, kiocb, &iter);
 		else
 			ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
+
+		if (!force_nonblock)
+			current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+
 		if (!force_nonblock || ret2 != -EAGAIN) {
 			io_rw_done(kiocb, ret2);
 		} else {

-- 
Jens Axboe