FAILED: patch "[PATCH] crypto: x86/aegis - Fix sleeping when disallowed on" failed to apply to 6.6-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.6-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-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x c7f49dadfcdf27e1f747442e874e9baa52ab7674
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082103-division-stoning-2306@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From c7f49dadfcdf27e1f747442e874e9baa52ab7674 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@kernel.org>
Date: Tue, 8 Jul 2025 12:38:28 -0700
Subject: [PATCH] crypto: x86/aegis - Fix sleeping when disallowed on
 PREEMPT_RT

skcipher_walk_done() can call kfree(), which takes a spinlock, which
makes it incorrect to call while preemption is disabled on PREEMPT_RT.
Therefore, end the kernel-mode FPU section before calling
skcipher_walk_done(), and restart it afterwards.

Moreover, pass atomic=false to skcipher_walk_aead_encrypt() instead of
atomic=true.  The point of atomic=true was to make skcipher_walk_done()
safe to call while in a kernel-mode FPU section, but that does not
actually work.  So just use the usual atomic=false.

Fixes: 1d373d4e8e15 ("crypto: x86 - Add optimized AEGIS implementations")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/x86/crypto/aegis128-aesni-glue.c b/arch/x86/crypto/aegis128-aesni-glue.c
index f1b6d40154e3..3cb5c193038b 100644
--- a/arch/x86/crypto/aegis128-aesni-glue.c
+++ b/arch/x86/crypto/aegis128-aesni-glue.c
@@ -119,7 +119,9 @@ crypto_aegis128_aesni_process_crypt(struct aegis_state *state,
 					   walk->dst.virt.addr,
 					   round_down(walk->nbytes,
 						      AEGIS128_BLOCK_SIZE));
+		kernel_fpu_end();
 		skcipher_walk_done(walk, walk->nbytes % AEGIS128_BLOCK_SIZE);
+		kernel_fpu_begin();
 	}
 
 	if (walk->nbytes) {
@@ -131,7 +133,9 @@ crypto_aegis128_aesni_process_crypt(struct aegis_state *state,
 			aegis128_aesni_dec_tail(state, walk->src.virt.addr,
 						walk->dst.virt.addr,
 						walk->nbytes);
+		kernel_fpu_end();
 		skcipher_walk_done(walk, 0);
+		kernel_fpu_begin();
 	}
 }
 
@@ -176,9 +180,9 @@ crypto_aegis128_aesni_crypt(struct aead_request *req,
 	struct aegis_state state;
 
 	if (enc)
-		skcipher_walk_aead_encrypt(&walk, req, true);
+		skcipher_walk_aead_encrypt(&walk, req, false);
 	else
-		skcipher_walk_aead_decrypt(&walk, req, true);
+		skcipher_walk_aead_decrypt(&walk, req, false);
 
 	kernel_fpu_begin();