From: Richard Cochran <richardcoch...@gmail.com> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 1b9f23727abb92c5e58f139e7d180befcaa06fe0 upstream. The posix_clock_poll function is supposed to return a bit mask of POLLxxx values. However, in case the hardware has disappeared (due to hot plugging for example) this code returns -ENODEV in a futile attempt to throw an error at the file descriptor level. The kernel's file_operations interface does not accept such error codes from the poll method. Instead, this function aught to return POLLERR. The value -ENODEV does, in fact, contain the POLLERR bit (and almost all the other POLLxxx bits as well), but only by chance. This patch fixes code to return a proper bit mask. Credit goes to Markus Elfring for pointing out the suspicious signed/unsigned mismatch. Reported-by: Markus Elfring <elfr...@users.sourceforge.net> igned-off-by: Richard Cochran <richardcoch...@gmail.com> Cc: John Stultz <john.stu...@linaro.org> Cc: Julia Lawall <julia.law...@lip6.fr> Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcoch...@gmail.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Jiri Slaby <jsl...@suse.cz> --- kernel/time/posix-clock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c index ce033c7aa2e8..9cff0ab82b63 100644 --- a/kernel/time/posix-clock.c +++ b/kernel/time/posix-clock.c @@ -69,10 +69,10 @@ static ssize_t posix_clock_read(struct file *fp, char __user *buf, static unsigned int posix_clock_poll(struct file *fp, poll_table *wait) { struct posix_clock *clk = get_posix_clock(fp); - int result = 0; + unsigned int result = 0; if (!clk) - return -ENODEV; + return POLLERR; if (clk->ops.poll) result = clk->ops.poll(clk, fp, wait); -- 2.7.2
