Messages in this thread Patch in this message |  | | Date | Tue, 29 Dec 2015 02:36:43 -0800 | From | tip-bot for Richard Cochran <> | Subject | [tip:timers/urgent] posix-clock: Fix return code on the poll method's error path |
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Commit-ID: 1b9f23727abb92c5e58f139e7d180befcaa06fe0 Gitweb: http://git.kernel.org/tip/1b9f23727abb92c5e58f139e7d180befcaa06fe0 Author: Richard Cochran <richardcochran@gmail.com> AuthorDate: Tue, 22 Dec 2015 22:19:58 +0100 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Tue, 29 Dec 2015 11:33:06 +0100
posix-clock: Fix return code on the poll method's error path
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 <elfring@users.sourceforge.net> igned-off-by: Richard Cochran <richardcochran@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Julia Lawall <julia.lawall@lip6.fr> Link: http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcochran@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- 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 ce033c7..9cff0ab 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);
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