Messages in this thread Patch in this message | | | Date | Tue, 30 Nov 2021 23:08:42 -0000 | From | "tip-bot2 for Mark Rutland" <> | Subject | [tip: core/entry] ARM: Snapshot thread flags |
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The following commit has been merged into the core/entry branch of tip:
Commit-ID: 050e22bfc4f450d342dbb7eaea470858ad567bce Gitweb: https://git.kernel.org/tip/050e22bfc4f450d342dbb7eaea470858ad567bce Author: Mark Rutland <mark.rutland@arm.com> AuthorDate: Mon, 29 Nov 2021 13:06:47 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Wed, 01 Dec 2021 00:06:43 +01:00
ARM: 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: Russell King <linux@armlinux.org.uk> Link: https://lore.kernel.org/r/20211129130653.2037928-6-mark.rutland@arm.com
--- arch/arm/kernel/signal.c | 2 +- arch/arm/mm/alignment.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index a41e27a..c532a60 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -631,7 +631,7 @@ 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; } diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c index ea81e89..adbb381 100644 --- a/arch/arm/mm/alignment.c +++ b/arch/arm/mm/alignment.c @@ -990,7 +990,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) * there is no work pending for this thread. */ raw_local_irq_disable(); - if (!(current_thread_info()->flags & _TIF_WORK_MASK)) + if (!(read_thread_flags() & _TIF_WORK_MASK)) set_cr(cr_no_alignment); }
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