Messages in this thread Patch in this message | | | From | Christian Schoenebeck <> | Date | Thu, 16 Jun 2022 19:09:42 +0200 | Subject | [PATCH] net/9p: show warning on Tread/Twrite if wrong file mode |
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The netfs changes (eb497943fa21) introduced cases where 'Tread' was sent to 9p server on a fid that was opened in write-only file mode. It took some time to find the cause of the symptoms observed (EBADF errors in user space apps). Add warnings to detect such issues easier in future.
Signed-off-by: Christian Schoenebeck <linux_oss@crudebyte.com> Link: https://lore.kernel.org/netdev/3645230.Tf70N6zClz@silver/ --- As requested by Dominique, here a clean version of my previous EBADF trap code to be merged. Dominique, if you already have an equivalent patch queued, then just go ahead. I don't mind.
I'm currently testing your EBADF fix patch and the discussed, slightly adjusted versions. Looking good so far, but I'll report back later on.
net/9p/client.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/9p/client.c b/net/9p/client.c index 8bba0d9cf975..05dead12702d 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -1555,6 +1555,8 @@ p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err) int total = 0; *err = 0; + WARN_ON((fid->mode & O_ACCMODE) == O_WRONLY); + while (iov_iter_count(to)) { int count; @@ -1648,6 +1650,8 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err) p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n", fid->fid, offset, iov_iter_count(from)); + WARN_ON((fid->mode & O_ACCMODE) == O_RDONLY); + while (iov_iter_count(from)) { int count = iov_iter_count(from); int rsize = fid->iounit; -- 2.30.2
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