Commit-ID: 337f13046ff03717a9e99675284a817527440a49 Gitweb: http://git.kernel.org/tip/337f13046ff03717a9e99675284a817527440a49 Author: Darren Hart <dvh...@linux.intel.com> AuthorDate: Fri, 18 Dec 2015 13:36:37 -0800 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Sun, 20 Dec 2015 12:43:25 +0100
futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op While reviewing Michael Kerrisk's recent futex manpage update, I noticed that we allow the FUTEX_CLOCK_REALTIME flag for FUTEX_WAIT_BITSET but not for FUTEX_WAIT. FUTEX_WAIT is treated as a simple version for FUTEX_WAIT_BITSET internally (with a bitmask of FUTEX_BITSET_MATCH_ANY). As such, I cannot come up with a reason for this exclusion for FUTEX_WAIT. This change does modify the behavior of the futex syscall, changing a call with FUTEX_WAIT | FUTEX_CLOCK_REALTIME from returning -ENOSYS, to be equivalent to FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME with a bitset of FUTEX_BITSET_MATCH_ANY. Reported-by: Michael Kerrisk <mtk.manpa...@gmail.com> Signed-off-by: Darren Hart <dvh...@linux.intel.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Davidlohr Bueso <d...@stgolabs.net> Link: http://lkml.kernel.org/r/9f3bdc116d79d23f5ee72ceb9a2a857f5ff8fa29.1450474525.git.dvh...@linux.intel.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- kernel/futex.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/futex.c b/kernel/futex.c index 461d438..8a310e2 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -3084,7 +3084,8 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, if (op & FUTEX_CLOCK_REALTIME) { flags |= FLAGS_CLOCKRT; - if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI) + if (cmd != FUTEX_WAIT && cmd != FUTEX_WAIT_BITSET && \ + cmd != FUTEX_WAIT_REQUEUE_PI) return -ENOSYS; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
