FAILED: patch "[PATCH] misc: fastrpc: fix possible map leak in fastrpc_put_args" failed to apply to 5.4-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.4-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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x da1ba64176e0138f2bfa96f9e43e8c3640d01e1e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025101312-express-attractor-1757@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From da1ba64176e0138f2bfa96f9e43e8c3640d01e1e Mon Sep 17 00:00:00 2001
From: Ling Xu <quic_lxu5@quicinc.com>
Date: Fri, 12 Sep 2025 14:12:35 +0100
Subject: [PATCH] misc: fastrpc: fix possible map leak in fastrpc_put_args

copy_to_user() failure would cause an early return without cleaning up
the fdlist, which has been updated by the DSP. This could lead to map
leak. Fix this by redirecting to a cleanup path on failure, ensuring
that all mapped buffers are properly released before returning.

Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method")
Cc: stable@kernel.org
Co-developed-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
Signed-off-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
Signed-off-by: Ling Xu <quic_lxu5@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://lore.kernel.org/r/20250912131236.303102-4-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index 1815b1e0c607..d950a179bff8 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -1085,6 +1085,7 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
 	struct fastrpc_phy_page *pages;
 	u64 *fdlist;
 	int i, inbufs, outbufs, handles;
+	int ret = 0;
 
 	inbufs = REMOTE_SCALARS_INBUFS(ctx->sc);
 	outbufs = REMOTE_SCALARS_OUTBUFS(ctx->sc);
@@ -1100,14 +1101,17 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
 			u64 len = rpra[i].buf.len;
 
 			if (!kernel) {
-				if (copy_to_user((void __user *)dst, src, len))
-					return -EFAULT;
+				if (copy_to_user((void __user *)dst, src, len)) {
+					ret = -EFAULT;
+					goto cleanup_fdlist;
+				}
 			} else {
 				memcpy(dst, src, len);
 			}
 		}
 	}
 
+cleanup_fdlist:
 	/* Clean up fdlist which is updated by DSP */
 	for (i = 0; i < FASTRPC_MAX_FDLIST; i++) {
 		if (!fdlist[i])
@@ -1116,7 +1120,7 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
 			fastrpc_map_put(mmap);
 	}
 
-	return 0;
+	return ret;
 }
 
 static int fastrpc_invoke_send(struct fastrpc_session_ctx *sctx,