This is a note to let you know that I've just added the patch titled
arm64/fpsimd: Clear SME state in the target task when setting the VL
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-fpsimd-clear-sme-state-in-the-target-task-when-setting-the-vl.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c9bb40b7f786662e33d71afe236442b0b61f0446 Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie@xxxxxxxxxx>
Date: Thu, 3 Aug 2023 00:46:39 +0100
Subject: arm64/fpsimd: Clear SME state in the target task when setting the VL
From: Mark Brown <broonie@xxxxxxxxxx>
commit c9bb40b7f786662e33d71afe236442b0b61f0446 upstream.
When setting SME vector lengths we clear TIF_SME to reenable SME traps,
doing a reallocation of the backing storage on next use. We do this using
clear_thread_flag() which operates on the current thread, meaning that when
setting the vector length via ptrace we may both not force traps for the
target task and force a spurious flush of any SME state that the tracing
task may have.
Clear the flag in the target task.
Fixes: e12310a0d30f ("arm64/sme: Implement ptrace support for streaming mode SVE registers")
Reported-by: David Spickett <David.Spickett@xxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230803-arm64-fix-ptrace-tif-sme-v1-1-88312fd6fbfd@xxxxxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/fpsimd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -910,7 +910,7 @@ int vec_set_vector_length(struct task_st
*/
task->thread.svcr &= ~(SVCR_SM_MASK |
SVCR_ZA_MASK);
- clear_thread_flag(TIF_SME);
+ clear_tsk_thread_flag(task, TIF_SME);
free_sme = true;
}
}
Patches currently in stable-queue which might be from broonie@xxxxxxxxxx are
queue-6.4/net-netsec-ignore-phy-mode-on-synquacer-in-dt-mode.patch
queue-6.4/arm64-ptrace-flush-fp-state-when-setting-zt0.patch
queue-6.4/arm64-fpsimd-sync-fpsimd-state-with-sve-for-sme-only-systems.patch
queue-6.4/arm64-fpsimd-clear-sme-state-in-the-target-task-when-setting-the-vl.patch
queue-6.4/arm64-ptrace-don-t-enable-sve-when-setting-streaming-sve.patch
queue-6.4/arm64-fpsimd-sync-and-zero-pad-fpsimd-state-for-streaming-sve.patch
