From: "tip-bot2 for Mark Rutland" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: core/entry] entry: Snapshot thread flags
Date: Fri, 26 Nov 2021 20:22:59 -0000 [thread overview]
Message-ID: <163795817992.11128.13208010629553686739.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20211117163050.53986-3-mark.rutland@arm.com>
The following commit has been merged into the core/entry branch of tip:
Commit-ID: f6af43531342c55c34a851bd455508edc29f6e06
Gitweb: https://git.kernel.org/tip/f6af43531342c55c34a851bd455508edc29f6e06
Author: Mark Rutland <mark.rutland@arm.com>
AuthorDate: Wed, 17 Nov 2021 16:30:40
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 26 Nov 2021 21:20:13 +01:00
entry: Snapshot thread flags
Some thread flags can be set remotely, and so even when IRQs are
disabled, the flags can change under our feet. Generally this is
unlikely to cause a problem in practice, but it is somewhat unsound, and
KCSAN will legitimately warn that there is a data race.
To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.
Convert them all to the new flag accessor helpers.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20211117163050.53986-3-mark.rutland@arm.com
---
include/linux/entry-kvm.h | 2 +-
kernel/entry/common.c | 4 ++--
kernel/entry/kvm.c | 4 ++--
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/include/linux/entry-kvm.h b/include/linux/entry-kvm.h
index 0d7865a..07c878d 100644
--- a/include/linux/entry-kvm.h
+++ b/include/linux/entry-kvm.h
@@ -75,7 +75,7 @@ static inline void xfer_to_guest_mode_prepare(void)
*/
static inline bool __xfer_to_guest_mode_work_pending(void)
{
- unsigned long ti_work = READ_ONCE(current_thread_info()->flags);
+ unsigned long ti_work = read_thread_flags();
return !!(ti_work & XFER_TO_GUEST_MODE_WORK);
}
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index d5a61d5..bad7136 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -187,7 +187,7 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
/* Check if any of the above work has queued a deferred wakeup */
tick_nohz_user_enter_prepare();
- ti_work = READ_ONCE(current_thread_info()->flags);
+ ti_work = read_thread_flags();
}
/* Return the latest work state for arch_exit_to_user_mode() */
@@ -196,7 +196,7 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
static void exit_to_user_mode_prepare(struct pt_regs *regs)
{
- unsigned long ti_work = READ_ONCE(current_thread_info()->flags);
+ unsigned long ti_work = read_thread_flags();
lockdep_assert_irqs_disabled();
diff --git a/kernel/entry/kvm.c b/kernel/entry/kvm.c
index 49972ee..96d476e 100644
--- a/kernel/entry/kvm.c
+++ b/kernel/entry/kvm.c
@@ -26,7 +26,7 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work)
if (ret)
return ret;
- ti_work = READ_ONCE(current_thread_info()->flags);
+ ti_work = read_thread_flags();
} while (ti_work & XFER_TO_GUEST_MODE_WORK || need_resched());
return 0;
}
@@ -43,7 +43,7 @@ int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu)
* disabled in the inner loop before going into guest mode. No need
* to disable interrupts here.
*/
- ti_work = READ_ONCE(current_thread_info()->flags);
+ ti_work = read_thread_flags();
if (!(ti_work & XFER_TO_GUEST_MODE_WORK))
return 0;
next prev parent reply other threads:[~2021-11-26 20:25 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 16:30 [PATCHv7 00/11] thread_info: use helpers to snapshot thread flags Mark Rutland
2021-11-17 16:30 ` [PATCHv7 01/11] thread_info: add " Mark Rutland
2021-11-26 20:23 ` [tip: core/entry] thread_info: Add " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 02/11] entry: " Mark Rutland
2021-11-26 20:22 ` tip-bot2 for Mark Rutland [this message]
2021-11-17 16:30 ` [PATCHv7 03/11] sched: " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] sched: Snapshot " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 04/11] alpha: snapshot " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] alpha: Snapshot " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 05/11] arm: snapshot " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] ARM: Snapshot " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 06/11] arm64: snapshot " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 07/11] microblaze: " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] microblaze: Snapshot " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 08/11] openrisc: snapshot " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] openrisc: Snapshot " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 09/11] powerpc: avoid discarding flags in system_call_exception() Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] powerpc: Avoid " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 10/11] powerpc: snapshot thread flags Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] powerpc: Snapshot " tip-bot2 for Mark Rutland
2021-11-17 16:30 ` [PATCHv7 11/11] x86: snapshot " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] x86: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 [PATCH v8 02/11] entry: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] entry: Snapshot " tip-bot2 for Mark Rutland
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