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| author | Jens Axboe <axboe@kernel.dk> | 2024-04-02 16:16:03 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-04-02 19:03:27 -0600 |
| commit | 561e4f9451d65fc2f7eef564e0064373e3019793 (patch) | |
| tree | 2e64d28297c67422596b02f7504fe734a554676a /io_uring/io_uring.c | |
| parent | 6b69c4ab4f685327d9e10caf0d84217ba23a8c4b (diff) | |
| download | linux-561e4f9451d65fc2f7eef564e0064373e3019793.tar.gz linux-561e4f9451d65fc2f7eef564e0064373e3019793.tar.bz2 linux-561e4f9451d65fc2f7eef564e0064373e3019793.zip | |
io_uring/kbuf: hold io_buffer_list reference over mmap
If we look up the kbuf, ensure that it doesn't get unregistered until
after we're done with it. Since we're inside mmap, we cannot safely use
the io_uring lock. Rely on the fact that we can lookup the buffer list
under RCU now and grab a reference to it, preventing it from being
unregistered until we're done with it. The lookup returns the
io_buffer_list directly with it referenced.
Cc: stable@vger.kernel.org # v6.4+
Fixes: 5cf4f52e6d8a ("io_uring: free io_buffer_list entries via RCU")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/io_uring.c')
| -rw-r--r-- | io_uring/io_uring.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index bc730f59265f..4521c2b66b98 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3447,14 +3447,15 @@ static void *io_uring_validate_mmap_request(struct file *file, ptr = ctx->sq_sqes; break; case IORING_OFF_PBUF_RING: { + struct io_buffer_list *bl; unsigned int bgid; bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT; - rcu_read_lock(); - ptr = io_pbuf_get_address(ctx, bgid); - rcu_read_unlock(); - if (!ptr) - return ERR_PTR(-EINVAL); + bl = io_pbuf_get_bl(ctx, bgid); + if (IS_ERR(bl)) + return bl; + ptr = bl->buf_ring; + io_put_bl(ctx, bl); break; } default: |