linux-kernel - [tip: core/entry] openrisc: Snapshot thread flags

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Message-ID: <163831371954.11128.4722786129563972807.tip-bot2@tip-bot2>
Date:   Tue, 30 Nov 2021 23:08:39 -0000
From:   "tip-bot2 for Mark Rutland" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Mark Rutland <mark.rutland@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Stafford Horne <shorne@...il.com>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Jonas Bonn <jonas@...thpole.se>,
        Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: core/entry] openrisc: Snapshot thread flags

The following commit has been merged into the core/entry branch of tip:

Commit-ID:     4ea7ce0a79b9450b71b9a88f9f5adbfe2bc3f2e5
Gitweb:        https://git.kernel.org/tip/4ea7ce0a79b9450b71b9a88f9f5adbfe2bc3f2e5
Author:        Mark Rutland <mark.rutland@....com>
AuthorDate:    Mon, 29 Nov 2021 13:06:50 
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 01 Dec 2021 00:06:44 +01:00

openrisc: 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@....com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Stafford Horne <shorne@...il.com>
Acked-by: Paul E. McKenney <paulmck@...nel.org>
Cc: Jonas Bonn <jonas@...thpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>
Link: https://lore.kernel.org/r/20211129130653.2037928-9-mark.rutland@arm.com

---
 arch/openrisc/kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/openrisc/kernel/signal.c b/arch/openrisc/kernel/signal.c
index 99516c9..92c5b70 100644
--- a/arch/openrisc/kernel/signal.c
+++ b/arch/openrisc/kernel/signal.c
@@ -313,7 +313,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 			}
 		}
 		local_irq_disable();
-		thread_flags = current_thread_info()->flags;
+		thread_flags = read_thread_flags();
 	} while (thread_flags & _TIF_WORK_MASK);
 	return 0;
 }