| Message ID | 20230508020120.218494-9-rmclure@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | powerpc: KCSAN fix warnings and mark accesses | expand |
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 > > Signed-off-by: Rohan McLure <rmclure@linux.ibm.com> > --- > 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
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; }
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. Signed-off-by: Rohan McLure <rmclure@linux.ibm.com> --- arch/powerpc/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)