| Message ID | 20180108053542.6472-5-ebiggers3@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Jan 07, 2018 at 09:35:39PM -0800, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > With pipe-user-pages-hard set to 'N', users were actually only allowed > up to 'N - 1' buffers; and likewise for pipe-user-pages-soft. > > Fix this to allow up to 'N' buffers, as would be expected. Interesting. I was a bit surprized at first and found that this was changed by b0b91d1 ("pipe: fix limit checking in pipe_set_size()"). Prior to this fix, only already allocated pipes were counted. After the fix, an allocation attempt was made before checking the size. So I think that your fix is needed in stable versions which backported the commit above. > Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Willy Tarreau <w@1wt.eu> Thanks, Willy
diff --git a/fs/pipe.c b/fs/pipe.c index 847ecc388820..9f20e7128578 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -605,12 +605,12 @@ static unsigned long account_pipe_buffers(struct user_struct *user, static bool too_many_pipe_buffers_soft(unsigned long user_bufs) { - return pipe_user_pages_soft && user_bufs >= pipe_user_pages_soft; + return pipe_user_pages_soft && user_bufs > pipe_user_pages_soft; } static bool too_many_pipe_buffers_hard(unsigned long user_bufs) { - return pipe_user_pages_hard && user_bufs >= pipe_user_pages_hard; + return pipe_user_pages_hard && user_bufs > pipe_user_pages_hard; } static bool is_unprivileged_user(void)