linux-kernel - [PATCH v2 7/9] microblaze: snapshot thread flags

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Message-Id: <20210621090602.16883-9-mark.rutland@arm.com>
Date:   Mon, 21 Jun 2021 10:06:00 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-kernel@...r.kernel.org
Cc:     boqun.feng@...il.com, bp@...en8.de, catalin.marinas@....com,
        dvyukov@...gle.com, elver@...gle.com, ink@...assic.park.msu.ru,
        jonas@...thpole.se, juri.lelli@...hat.com, linux@...linux.org.uk,
        luto@...nel.org, mark.rutland@....com, mattst88@...il.com,
        mingo@...hat.com, monstr@...str.eu, paulmck@...nel.org,
        peterz@...radead.org, rth@...ddle.net, shorne@...il.com,
        stefan.kristiansson@...nalahti.fi, tglx@...utronix.de,
        vincent.guittot@...aro.org, will@...nel.org
Subject: [PATCH v2 7/9] microblaze: 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>
Cc: Michal Simek <monstr@...str.eu>
---
 arch/microblaze/kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/microblaze/kernel/signal.c b/arch/microblaze/kernel/signal.c
index fc61eb0eb8dd..23e8a9336a29 100644
--- a/arch/microblaze/kernel/signal.c
+++ b/arch/microblaze/kernel/signal.c
@@ -283,7 +283,7 @@ static void do_signal(struct pt_regs *regs, int in_syscall)
 #ifdef DEBUG_SIG
 	pr_info("do signal: %p %d\n", regs, in_syscall);
 	pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
-			regs->r12, current_thread_info()->flags);
+			regs->r12, read_thread_flags());
 #endif
 
 	if (get_signal(&ksig)) {
-- 
2.11.0