The patch titled
futex: restartable futex_wait
has been added to the -mm tree. Its filename is
futex-restartable-futex_wait.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: futex: restartable futex_wait
From: Nick Piggin <npiggin@xxxxxxx>
LTP test sigaction_16_24 fails, because it expects sem_wait to be restarted
if SA_RESTART is set. sem_wait is implemented with futex_wait, that
currently doesn't support being restarted. Ulrich confirms that the call
should be restartable.
Implement a restart_block method to handle the relative timeout, and allow
restarts.
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Cc: Ulrich Drepper <drepper@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/futex.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff -puN kernel/futex.c~futex-restartable-futex_wait kernel/futex.c
--- a/kernel/futex.c~futex-restartable-futex_wait
+++ a/kernel/futex.c
@@ -978,6 +978,7 @@ static void unqueue_me_pi(struct futex_q
drop_futex_key_refs(&q->key);
}
+static long futex_wait_restart(struct restart_block *restart);
static int futex_wait(u32 __user *uaddr, u32 val, unsigned long time)
{
struct task_struct *curr = current;
@@ -1077,11 +1078,22 @@ static int futex_wait(u32 __user *uaddr,
return 0;
if (time == 0)
return -ETIMEDOUT;
+
/*
* We expect signal_pending(current), but another thread may
* have handled it for us already.
*/
- return -EINTR;
+ if (time == MAX_SCHEDULE_TIMEOUT)
+ return -ERESTARTSYS;
+ else {
+ struct restart_block *restart;
+ restart = ¤t_thread_info()->restart_block;
+ restart->fn = futex_wait_restart;
+ restart->arg0 = (unsigned long)uaddr;
+ restart->arg1 = (unsigned long)val;
+ restart->arg2 = time;
+ return -ERESTART_RESTARTBLOCK;
+ }
out_unlock_release_sem:
queue_unlock(&q, hb);
@@ -1091,6 +1103,17 @@ static int futex_wait(u32 __user *uaddr,
return ret;
}
+static long futex_wait_restart(struct restart_block *restart)
+{
+ u32 __user *uaddr = (u32 __user *)restart->arg0;
+ u32 val = (u32)restart->arg1;
+ unsigned long time = restart->arg2;
+
+ restart->fn = do_no_restart_syscall;
+ return (long)futex_wait(uaddr, val, time);
+}
+
+
/*
* Userspace tried a 0 -> TID atomic transition of the futex value
* and failed. The kernel side here does the whole locking operation:
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
mm-fix-madvise-infinine-loop.patch
futex-restartable-futex_wait.patch
mm-remove-gcc-workaround.patch
mm-more-rmap-checking.patch
mm-make-read_cache_page-synchronous.patch
fs-buffer-dont-pageuptodate-without-page-locked.patch
mm-debug-check-for-the-fault-vs-invalidate-race.patch
mm-debug-check-for-the-fault-vs-invalidate-race-tidy.patch
mm-simplify-filemap_nopage.patch
mm-fix-fault-vs-invalidate-race-for-linear-mappings.patch
mm-merge-populate-and-nopage-into-fault-fixes-nonlinear.patch
mm-merge-populate-and-nopage-into-fault-fixes-nonlinear-tidy.patch
mm-merge-nopfn-into-fault.patch
mm-remove-legacy-cruft.patch
mm-fix-clear_page_dirty_for_io-vs-fault-race.patch
exec-fix-remove_arg_zero.patch
exec-fix-remove_arg_zero-add-comment.patch
-
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