Messages in this thread Patch in this message | | | From | Mark Rutland <> | Subject | [RFC PATCH 05/10] arm: snapshot thread flags | Date | Wed, 9 Jun 2021 13:19:56 +0100 |
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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, we should snapshot the flags prior to using them. Let's use the new helpers to do so on arm.
Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Russell King <linux@armlinux.org.uk> --- 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 a3a38d0a4c85..40c1178bd8c2 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -674,7 +674,7 @@ 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 ea81e89e7740..adbb3817d0be 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); } -- 2.11.0
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