The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x dc7eb8755797ed41a0d1b5c0c39df3c8f401b3d9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024012617-overlap-reborn-e124@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

dc7eb8755797 ("arm64/sme: Always exit sme_alloc() early with existing storage") 5d0a8d2fba50 ("arm64/ptrace: Ensure that SME is set up for target when writing SSVE state") f90b529bcbe5 ("arm64/sme: Implement ZT0 ptrace support") ce514000da4f ("arm64/sme: Rename za_state to sme_state") 1192b93ba352 ("arm64/fp: Use a struct to pass data to fpsimd_bind_state_to_cpu()") deeb8f9a80fd ("arm64/fpsimd: Have KVM explicitly say which FP registers to save") baa8515281b3 ("arm64/fpsimd: Track the saved FPSIMD state type separately to TIF_SVE") 93ae6b01bafe ("KVM: arm64: Discard any SVE state when entering KVM guests")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From dc7eb8755797ed41a0d1b5c0c39df3c8f401b3d9 Mon Sep 17 00:00:00 2001 From: Mark Brown broonie@kernel.org Date: Mon, 15 Jan 2024 20:15:46 +0000 Subject: [PATCH] arm64/sme: Always exit sme_alloc() early with existing storage

When sme_alloc() is called with existing storage and we are not flushing we will always allocate new storage, both leaking the existing storage and corrupting the state. Fix this by separating the checks for flushing and for existing storage as we do for SVE.

Callers that reallocate (eg, due to changing the vector length) should call sme_free() themselves.

Fixes: 5d0a8d2fba50 ("arm64/ptrace: Ensure that SME is set up for target when writing SSVE state") Signed-off-by: Mark Brown broonie@kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240115-arm64-sme-flush-v1-1-7472bd3459b7@kernel.... Signed-off-by: Will Deacon will@kernel.org

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 0983be2b1b61..a5dc6f764195 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1217,8 +1217,10 @@ void fpsimd_release_task(struct task_struct *dead_task) */ void sme_alloc(struct task_struct *task, bool flush) { - if (task->thread.sme_state && flush) { - memset(task->thread.sme_state, 0, sme_state_size(task)); + if (task->thread.sme_state) { + if (flush) + memset(task->thread.sme_state, 0, + sme_state_size(task)); return; }