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From: Mark Rutland <mark.rutland@arm.com>
To: linux-kernel@vger.kernel.org
Cc: boqun.feng@gmail.com, bp@alien8.de, catalin.marinas@arm.com,
	dvyukov@google.com, elver@google.com, ink@jurassic.park.msu.ru,
	jonas@southpole.se, juri.lelli@redhat.com, linux@armlinux.org.uk,
	luto@kernel.org, mark.rutland@arm.com, mattst88@gmail.com,
	mingo@redhat.com, monstr@monstr.eu, paulmck@kernel.org,
	peterz@infradead.org, rth@twiddle.net, shorne@gmail.com,
	stefan.kristiansson@saunalahti.fi, tglx@linutronix.de,
	vincent.guittot@linaro.org, will@kernel.org
Subject: [PATCH v2 7/9] microblaze: snapshot thread flags
Date: Mon, 21 Jun 2021 10:06:00 +0100	[thread overview]
Message-ID: <20210621090602.16883-9-mark.rutland@arm.com> (raw)
In-Reply-To: <20210621090602.16883-1-mark.rutland@arm.com>

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>
Cc: Michal Simek <monstr@monstr.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


  parent reply	other threads:[~2021-06-21  9:06 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-21  9:05 [PATCH v2 0/9] thread_info: use helpers to snapshot thread flags Mark Rutland
2021-06-21  9:05 ` [PATCH v2 1/9] thread_info: add " Mark Rutland
2021-06-21  9:05 ` [PATCH v2 2/9] entry: " Mark Rutland
2021-06-21  9:05 ` [PATCH v2 3/9] sched: " Mark Rutland
2021-06-21  9:05 ` [PATCH v2 4/9] alpha: " Mark Rutland
2021-06-21  9:05 ` [PATCH v2 5/9] arm: " Mark Rutland
2021-06-21  9:05 ` [PATCH v2 6/9] arm64: read " Mark Rutland
2021-06-21  9:05 ` [PATCH v2 6/9] arm64: snapshot " Mark Rutland
2021-06-21  9:06 ` Mark Rutland [this message]
2021-06-21  9:06 ` [PATCH v2 8/9] openrisc: " Mark Rutland
2021-06-21  9:06 ` [PATCH v2 9/9] x86: " Mark Rutland
2021-06-21 17:54 ` [PATCH v2 0/9] thread_info: use helpers to " Will Deacon
2021-06-22 14:45   ` Mark Rutland

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