From b85a0e91d7d6cd06a53c881a46f749cfcef416a2 Mon Sep 17 00:00:00 2001 From: Junrui Luo Date: Fri, 24 Jul 2026 23:33:39 +0100 Subject: [PATCH] misc: fastrpc: take fl->lock when moving mmaps on interrupted invoke When an invoke is interrupted by a signal, wait_for_completion_interruptible() returns -ERESTARTSYS and fastrpc_internal_invoke() moves every buffer from fl->mmaps onto cctx->invoke_interrupted_mmaps. This list_del()/list_add_tail() walk runs without holding fl->lock, the lock that serialises fl->mmaps in fastrpc_req_mmap() and fastrpc_req_munmap() everywhere else. Take fl->lock around the move, matching every other fl->mmaps accessor. Fixes: 76e8e4ace1ed ("misc: fastrpc: Safekeep mmaps on interrupted invoke") Reported-by: Yuhao Jiang Cc: stable@vger.kernel.org Signed-off-by: Junrui Luo Reviewed-by: Dmitry Baryshkov Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20260724223342.629168-4-srini@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/misc/fastrpc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 12dcd2e737c3..c75eafe872cc 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -1305,10 +1305,12 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl, u32 kernel, } if (err == -ERESTARTSYS) { + spin_lock(&fl->lock); list_for_each_entry_safe(buf, b, &fl->mmaps, node) { list_del(&buf->node); list_add_tail(&buf->node, &fl->cctx->invoke_interrupted_mmaps); } + spin_unlock(&fl->lock); } if (err)