* [PATCH] Fix robust mutex daedlock [BZ #20263]
@ 2016-06-23 19:26 Jiyoung Yun
2016-06-28 8:12 ` Torvald Riegel
0 siblings, 1 reply; 4+ messages in thread
From: Jiyoung Yun @ 2016-06-23 19:26 UTC (permalink / raw)
To: libc-alpha; +Cc: jy910.yun, Jiyoung Yun
In Linux/ARM environment, a robust mutex can't catch the timeout result
when it is already owned by other thread and requests to try lock with
a specific time value(pthread_mutex_timedlock). The futex already returns
the ETIMEDOUT result but there is no check the return value and it makes
a deadlock.
* nptl/lowlevelrobustlock.c: Implement ETIMEDOUT logic.
Signed-off-by: Jiyoung Yun <t2wish@gmail.com>
---
ChangeLog | 5 +++++
nptl/lowlevelrobustlock.c | 9 +++++++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 4bfee94..7b95767 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2016-06-24 Jiyoung Yun <t2wish@gmail.com>
+
+ [BZ #20263]
+ * nptl/lowlevelrobustlock.c: Implement ETIMEDOUT logic.
+
2016-06-23 Florian Weimer <fweimer@redhat.com>
* test-skeleton.c (xrealloc): Support deallocation with n == 0.
diff --git a/nptl/lowlevelrobustlock.c b/nptl/lowlevelrobustlock.c
index 3b988b2..8842032 100644
--- a/nptl/lowlevelrobustlock.c
+++ b/nptl/lowlevelrobustlock.c
@@ -113,15 +113,20 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
&& atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
continue;
+ int err;
/* If *futex == 2, wait until woken or timeout. */
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|| !defined lll_futex_timed_wait_bitset)
- lll_futex_timed_wait (futex, newval, &rt, private);
+ err = lll_futex_timed_wait (futex, newval, &rt, private);
#else
- lll_futex_timed_wait_bitset (futex, newval, abstime,
+ err = lll_futex_timed_wait_bitset (futex, newval, abstime,
FUTEX_CLOCK_REALTIME, private);
#endif
+ /* the futex call time out */
+ if (err == -ETIMEDOUT)
+ return ETIMEDOUT;
+
try:
;
}
--
1.9.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Fix robust mutex daedlock [BZ #20263]
2016-06-23 19:26 [PATCH] Fix robust mutex daedlock [BZ #20263] Jiyoung Yun
@ 2016-06-28 8:12 ` Torvald Riegel
0 siblings, 0 replies; 4+ messages in thread
From: Torvald Riegel @ 2016-06-28 8:12 UTC (permalink / raw)
To: Jiyoung Yun; +Cc: libc-alpha, jy910.yun, Andreas Schwab
On Fri, 2016-06-24 at 04:26 +0900, Jiyoung Yun wrote:
> In Linux/ARM environment, a robust mutex can't catch the timeout result
> when it is already owned by other thread and requests to try lock with
> a specific time value(pthread_mutex_timedlock). The futex already returns
> the ETIMEDOUT result but there is no check the return value and it makes
> a deadlock.
>
> * nptl/lowlevelrobustlock.c: Implement ETIMEDOUT logic.
This touches the same code Andreas Schwab had a patch for (but which
touches the other part of the preprocessor conditional). Can the two of
you create one patch that fixes this bug?
> Signed-off-by: Jiyoung Yun <t2wish@gmail.com>
> ---
> ChangeLog | 5 +++++
> nptl/lowlevelrobustlock.c | 9 +++++++--
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index 4bfee94..7b95767 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2016-06-24 Jiyoung Yun <t2wish@gmail.com>
> +
> + [BZ #20263]
> + * nptl/lowlevelrobustlock.c: Implement ETIMEDOUT logic.
> +
> 2016-06-23 Florian Weimer <fweimer@redhat.com>
>
> * test-skeleton.c (xrealloc): Support deallocation with n == 0.
> diff --git a/nptl/lowlevelrobustlock.c b/nptl/lowlevelrobustlock.c
> index 3b988b2..8842032 100644
> --- a/nptl/lowlevelrobustlock.c
> +++ b/nptl/lowlevelrobustlock.c
> @@ -113,15 +113,20 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
> && atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
> continue;
>
> + int err;
> /* If *futex == 2, wait until woken or timeout. */
> #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
> || !defined lll_futex_timed_wait_bitset)
> - lll_futex_timed_wait (futex, newval, &rt, private);
> + err = lll_futex_timed_wait (futex, newval, &rt, private);
> #else
> - lll_futex_timed_wait_bitset (futex, newval, abstime,
> + err = lll_futex_timed_wait_bitset (futex, newval, abstime,
> FUTEX_CLOCK_REALTIME, private);
> #endif
>
> + /* the futex call time out */
> + if (err == -ETIMEDOUT)
> + return ETIMEDOUT;
> +
> try:
> ;
> }
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Fix robust mutex daedlock [BZ #20263]
2016-06-29 16:15 ` [PATCH] " Jiyoung Yun
@ 2016-07-07 12:35 ` Andreas Schwab
0 siblings, 0 replies; 4+ messages in thread
From: Andreas Schwab @ 2016-07-07 12:35 UTC (permalink / raw)
To: Jiyoung Yun; +Cc: libc-alpha, jy910.yun
I have installed that now.
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] Fix robust mutex daedlock [BZ #20263]
2016-06-29 15:03 [PATCH v2 1/2] " Jiyoung Yun
@ 2016-06-29 16:15 ` Jiyoung Yun
2016-07-07 12:35 ` Andreas Schwab
0 siblings, 1 reply; 4+ messages in thread
From: Jiyoung Yun @ 2016-06-29 16:15 UTC (permalink / raw)
To: libc-alpha; +Cc: jy910.yun, Jiyoung Yun
In Linux/ARM environment, a robust mutex can't catch the timeout result
when it is already owned by other thread and requests to try lock with
a specific time value(pthread_mutex_timedlock). The futex already returns
the ETIMEDOUT result but there is no check the return value and it makes
a deadlock.
* nptl/lowlevelrobustlock.c: Implement ETIMEDOUT logic.
---
ChangeLog | 5 +++++
nptl/lowlevelrobustlock.c | 5 ++++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/ChangeLog b/ChangeLog
index 3da2eca..97461f6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2016-06-28 Jiyoung Yun <t2wish@gmail.com>
+
+ [BZ #20263]
+ * nptl/lowlevelrobustlock.c: Implement ETIMEDOUT logic.
+
2016-06-28 Richard Henderson <rth@redhat.com>
* elf/elf.h (EM_BPF): New.
diff --git a/nptl/lowlevelrobustlock.c b/nptl/lowlevelrobustlock.c
index 3b988b2..43caae7 100644
--- a/nptl/lowlevelrobustlock.c
+++ b/nptl/lowlevelrobustlock.c
@@ -118,8 +118,11 @@ __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
|| !defined lll_futex_timed_wait_bitset)
lll_futex_timed_wait (futex, newval, &rt, private);
#else
- lll_futex_timed_wait_bitset (futex, newval, abstime,
+ int err = lll_futex_timed_wait_bitset (futex, newval, abstime,
FUTEX_CLOCK_REALTIME, private);
+ /* the futex call time out */
+ if (err == -ETIMEDOUT)
+ return -err;
#endif
try:
--
1.9.1
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-07-07 12:35 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2016-06-23 19:26 [PATCH] Fix robust mutex daedlock [BZ #20263] Jiyoung Yun
2016-06-28 8:12 ` Torvald Riegel
2016-06-29 15:03 [PATCH v2 1/2] " Jiyoung Yun
2016-06-29 16:15 ` [PATCH] " Jiyoung Yun
2016-07-07 12:35 ` Andreas Schwab
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