From: David Howells Date: Fri, 11 Mar 2022 13:24:22 +0000 (+0000) Subject: watch_queue: Fix the alloc bitmap size to reflect notes allocated X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3b4c0371928c17af03e8397ac842346624017ce6;p=linux.git watch_queue: Fix the alloc bitmap size to reflect notes allocated Currently, watch_queue_set_size() sets the number of notes available in wqueue->nr_notes according to the number of notes allocated, but sets the size of the bitmap to the unrounded number of notes originally asked for. Fix this by setting the bitmap size to the number of notes we're actually going to make available (ie. the number allocated). Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reported-by: Jann Horn Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c index 5b516eb2c7ccb..9c476d2cbac03 100644 --- a/kernel/watch_queue.c +++ b/kernel/watch_queue.c @@ -243,6 +243,7 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes) goto error; } + nr_notes = nr_pages * WATCH_QUEUE_NOTES_PER_PAGE; ret = pipe_resize_ring(pipe, roundup_pow_of_two(nr_notes)); if (ret < 0) goto error; @@ -266,7 +267,7 @@ long watch_queue_set_size(struct pipe_inode_info *pipe, unsigned int nr_notes) wqueue->notes = pages; wqueue->notes_bitmap = bitmap; wqueue->nr_pages = nr_pages; - wqueue->nr_notes = nr_pages * WATCH_QUEUE_NOTES_PER_PAGE; + wqueue->nr_notes = nr_notes; return 0; error_p: