Re: [PATCH 08/12] powerpc: Annotate accesses to ipi message flags
From: "Nicholas Piggin" <npiggin@gmail.com>
Date: 2023-05-09 02:29:09
On Mon May 8, 2023 at 12:01 PM AEST, Rohan McLure wrote:
IPI message flags are observed and consequently consumed in the smp_ipi_demux_relaxed function, which handles these message sources until it observes none more arriving. Mark the checked loop guard with READ_ONCE, to signal to KCSAN that the read is known to be volatile, and that non-determinism is expected.
smp_muxed_ipi_set_message() doesn't need a WRITE_ONCE()? Thanks, Nick
quoted hunk ↗ jump to hunk
Signed-off-by: Rohan McLure <redacted> --- arch/powerpc/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 6b90f10a6c81..00b74d66b771 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c@@ -348,7 +348,7 @@ irqreturn_t smp_ipi_demux_relaxed(void) if (all & IPI_MESSAGE(PPC_MSG_NMI_IPI)) nmi_ipi_action(0, NULL); #endif - } while (info->messages); + } while (READ_ONCE(info->messages)); return IRQ_HANDLED; }-- 2.37.2