This is a note to let you know that I've just added the patch titled
futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
futex-do-not-apply-time-namespace-adjustment-on-futex_lock_pi.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cdf78db4070967869e4d027c11f4dd825d8f815a Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Thu, 22 Apr 2021 21:44:19 +0200
Subject: futex: Do not apply time namespace adjustment on FUTEX_LOCK_PI
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit cdf78db4070967869e4d027c11f4dd825d8f815a upstream.
FUTEX_LOCK_PI does not require to have the FUTEX_CLOCK_REALTIME bit set
because it has been using CLOCK_REALTIME based absolute timeouts
forever. Due to that, the time namespace adjustment which is applied when
FUTEX_CLOCK_REALTIME is not set, will wrongly take place for FUTEX_LOCK_PI
and wreckage the timeout.
Exclude it from that procedure.
Fixes: c2f7d08cccf4 ("futex: Adjust absolute futex timeouts with per time namespace offset")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20210422194704.984540159@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/futex.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3784,7 +3784,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uad
t = timespec64_to_ktime(ts);
if (cmd == FUTEX_WAIT)
t = ktime_add_safe(ktime_get(), t);
- else if (!(op & FUTEX_CLOCK_REALTIME))
+ else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
t = timens_ktime_to_host(CLOCK_MONOTONIC, t);
tp = &t;
}
@@ -3978,7 +3978,7 @@ SYSCALL_DEFINE6(futex_time32, u32 __user
t = timespec64_to_ktime(ts);
if (cmd == FUTEX_WAIT)
t = ktime_add_safe(ktime_get(), t);
- else if (!(op & FUTEX_CLOCK_REALTIME))
+ else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
t = timens_ktime_to_host(CLOCK_MONOTONIC, t);
tp = &t;
}
Patches currently in stable-queue which might be from tglx@xxxxxxxxxxxxx are
queue-5.10/posix-timers-preserve-return-value-in-clock_adjtime32.patch
queue-5.10/futex-do-not-apply-time-namespace-adjustment-on-futex_lock_pi.patch
queue-5.10/revert-337f13046ff0-futex-allow-futex_clock_realtime-with-futex_wait-op.patch
queue-5.10/genirq-matrix-prevent-allocation-counter-corruption.patch
queue-5.10/x86-cpu-initialize-msr_tsc_aux-if-rdtscp-or-rdpid-is-supported.patch
