Hi Greg, On 10/09/2024 09:32, Greg KH wrote:
On Mon, Sep 09, 2024 at 10:57:01AM +0800, WangYuli wrote:From: Andrea Parri <parri.andrea@xxxxxxxxx> [ Upstream commit d6cfd1770f20392d7009ae1fdb04733794514fa9 ] The membarrier system call requires a full memory barrier after storing to rq->curr, before going back to user-space. The barrier is only needed when switching between processes: the barrier is implied by mmdrop() when switching from kernel to userspace, and it's not needed when switching from userspace to kernel. Rely on the feature/mechanism ARCH_HAS_MEMBARRIER_CALLBACKS and on the primitive membarrier_arch_switch_mm(), already adopted by the PowerPC architecture, to insert the required barrier. Fixes: fab957c11efe2f ("RISC-V: Atomic and Locking Code") Signed-off-by: Andrea Parri <parri.andrea@xxxxxxxxx> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240131144936.29190-2-parri.andrea@xxxxxxxxx Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> Signed-off-by: WangYuli <wangyuli@xxxxxxxxxxxxx> --- MAINTAINERS | 2 +- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/membarrier.h | 31 +++++++++++++++++++++++++++++ arch/riscv/mm/context.c | 2 ++ kernel/sched/core.c | 5 +++-- 5 files changed, 38 insertions(+), 3 deletions(-) create mode 100644 arch/riscv/include/asm/membarrier.hNow queued up, thanks.
The original patch was merged in 6.9 and the Fixes tag points to a commit introduced in v4.15. So IIUC, this patch should have been backported "automatically" to the releases < 6.9 right? As stated in the documentation (process/stable-kernel-rules.html):
"Note, such tagging is unnecessary if the stable team can derive the appropriate versions from Fixes: tags."
Or did we miss something? Thanks, Alex
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