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Subject[tip: core/entry] alpha: Snapshot thread flags
The following commit has been merged into the core/entry branch of tip:

Commit-ID: 7fb2b24bb5c5876a3205cb5b9a580f81e8c9f744
Gitweb: https://git.kernel.org/tip/7fb2b24bb5c5876a3205cb5b9a580f81e8c9f744
Author: Mark Rutland <mark.rutland@arm.com>
AuthorDate: Mon, 29 Nov 2021 13:06:46
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 01 Dec 2021 00:06:43 +01:00

alpha: 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: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Link: https://lore.kernel.org/r/20211129130653.2037928-5-mark.rutland@arm.com

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

diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index bc077ba..d8ed71d 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -535,6 +535,6 @@ do_work_pending(struct pt_regs *regs, unsigned long thread_flags,
}
}
local_irq_disable();
- thread_flags = current_thread_info()->flags;
+ thread_flags = read_thread_flags();
} while (thread_flags & _TIF_WORK_MASK);
}
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