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watch_queue: Fix the alloc bitmap size to reflect notes allocated

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commit 3b4c037192 upstream.

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: c73be61ced ("pipe: Add general notification queue support")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
David Howells 2022-03-11 13:24:22 +00:00 • committed by Greg Kroah-Hartman
commit 880acbb718
1 changed files with 2 additions and 1 deletions
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3
kernel/watch_queue.c
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@ -244,6 +244,7 @@ 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;
@ -269,7 +270,7 @@ 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: