From: Mark Rutland Date: Mon, 29 Nov 2021 13:06:47 +0000 (+0000) Subject: ARM: Snapshot thread flags X-Git-Tag: v6.6.17~8503^2~5 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=050e22bfc4f450d342dbb7eaea470858ad567bce;p=platform%2Fkernel%2Flinux-rpi.git 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 Signed-off-by: Thomas Gleixner Acked-by: Paul E. McKenney Cc: Russell King Link: https://lore.kernel.org/r/20211129130653.2037928-6-mark.rutland@arm.com --- 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); }