Messages in this thread Patch in this message | | | Date | Fri, 24 Jan 2014 16:43:43 +0000 | From | Will Deacon <> | Subject | Re: [PATCH V2 4/6] ARM: Make PID_IN_CONTEXTIDR incompatible with PID_NS |
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On Fri, Jan 24, 2014 at 04:40:54PM +0000, Adrien Vergé wrote: > When using namespaces, different processes can have the same PID. > It makes no sense to store a PID value in the Context ID register > to track a specific process, when others share the same value. > > Consequently, PID_IN_CONTEXTIDR (which is used for tracing and > debugging processes) should not be compatible with PID_NS. > > Signed-off-by: Adrien Vergé <adrienverge@gmail.com> > --- > arch/arm/Kconfig.debug | 2 +- > arch/arm64/Kconfig.debug | 1 + > 2 files changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug > index 5765abf..ed46748 100644 > --- a/arch/arm/Kconfig.debug > +++ b/arch/arm/Kconfig.debug > @@ -1143,7 +1143,7 @@ config ARM_KPROBES_TEST > > config PID_IN_CONTEXTIDR > bool "Write the current PID to the CONTEXTIDR register" > - depends on CPU_COPY_V6 > + depends on CPU_COPY_V6 && !PID_NS > help > Enabling this option causes the kernel to write the current PID to > the PROCID field of the CONTEXTIDR register, at the expense of some > diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug > index 835c559..06b2633b 100644 > --- a/arch/arm64/Kconfig.debug > +++ b/arch/arm64/Kconfig.debug > @@ -17,6 +17,7 @@ config EARLY_PRINTK > > config PID_IN_CONTEXTIDR > bool "Write the current PID to the CONTEXTIDR register" > + depends on !PID_NS > help > Enabling this option causes the kernel to write the current PID to > the CONTEXTIDR register, at the expense of some additional
Are you sure about this? The value we write is actually task_pid_nr, which I believe to be globally unique.
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