[PATCH v6 4/5] imisc: fastrpc: Allocate entire reserved memory for Audio PD in probe
From: Jianping Li
Date: Tue May 26 2026 - 07:12:16 EST
Allocating and freeing Audio PD memory from userspace is unsafe because
the kernel cannot reliably determine when the DSP has finished using the
memory. Userspace may free buffers while they are still in use by the DSP,
and remote free requests cannot be safely trusted.
Additionally, the current implementation allows userspace to repeatedly
grow the Audio PD heap, but does not support shrinking it. This can lead
to unbounded memory usage over time, effectively causing a memory leak.
Fix this by allocating the entire Audio PD reserved-memory region during
rpmsg probe and tying its lifetime to the rpmsg channel. This removes
userspace-controlled alloc/free and ensures that memory is reclaimed only
when the DSP process is torn down.
Fixes: 0871561055e66 ("misc: fastrpc: Add support for audiopd")
Cc: stable@xxxxxxxxxx
Signed-off-by: Jianping Li <jianping.li@xxxxxxxxxxxxxxxx>
---
drivers/misc/fastrpc.c | 103 ++++++++++++++++++++---------------------
1 file changed, 50 insertions(+), 53 deletions(-)
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index f46a8f53970d..0208208c2d27 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -276,6 +276,8 @@ struct fastrpc_channel_ctx {
struct kref refcount;
/* Flag if dsp attributes are cached */
bool valid_attributes;
+ /* Flag if audio PD init mem was allocated */
+ bool audio_init_mem;
u32 dsp_attributes[FASTRPC_MAX_DSP_ATTRIBUTES];
struct fastrpc_device *secure_fdevice;
struct fastrpc_device *fdevice;
@@ -1344,15 +1346,16 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
struct fastrpc_init_create_static init;
struct fastrpc_invoke_args *args;
struct fastrpc_phy_page pages[1];
+ struct fastrpc_channel_ctx *cctx = fl->cctx;
char *name;
int err;
- bool scm_done = false;
struct {
int client_id;
u32 namelen;
u32 pageslen;
} inbuf;
u32 sc;
+ unsigned long flags;
if (!fl->cctx->remote_heap ||
!fl->cctx->remote_heap->dma_addr ||
@@ -1383,31 +1386,6 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
inbuf.client_id = fl->client_id;
inbuf.namelen = init.namelen;
inbuf.pageslen = 0;
- if (!fl->cctx->remote_heap) {
- err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
- &fl->cctx->remote_heap);
- if (err)
- goto err_name;
-
- /* Map if we have any heap VMIDs associated with this ADSP Static Process. */
- if (fl->cctx->vmcount) {
- u64 src_perms = BIT(QCOM_SCM_VMID_HLOS);
-
- err = qcom_scm_assign_mem(fl->cctx->remote_heap->dma_addr,
- (u64)fl->cctx->remote_heap->size,
- &src_perms,
- fl->cctx->vmperms, fl->cctx->vmcount);
- if (err) {
- dev_err(fl->sctx->dev,
- "Failed to assign memory with dma_addr %pad size 0x%llx err %d\n",
- &fl->cctx->remote_heap->dma_addr,
- fl->cctx->remote_heap->size, err);
- goto err_map;
- }
- scm_done = true;
- inbuf.pageslen = 1;
- }
- }
fl->pd = USER_PD;
@@ -1419,8 +1397,24 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
args[1].length = inbuf.namelen;
args[1].fd = -1;
- pages[0].addr = fl->cctx->remote_heap->dma_addr;
- pages[0].size = fl->cctx->remote_heap->size;
+ spin_lock_irqsave(&cctx->lock, flags);
+ if (!fl->cctx->audio_init_mem) {
+ if (!fl->cctx->remote_heap ||
+ !fl->cctx->remote_heap->dma_addr ||
+ !fl->cctx->remote_heap->size) {
+ spin_unlock_irqrestore(&cctx->lock, flags);
+ err = -ENOMEM;
+ goto err;
+ }
+ pages[0].addr = fl->cctx->remote_heap->dma_addr;
+ pages[0].size = fl->cctx->remote_heap->size;
+ fl->cctx->audio_init_mem = true;
+ inbuf.pageslen = 1;
+ } else {
+ pages[0].addr = 0;
+ pages[0].size = 0;
+ }
+ spin_unlock_irqrestore(&cctx->lock, flags);
args[2].ptr = (u64)(uintptr_t) pages;
args[2].length = sizeof(*pages);
@@ -1438,27 +1432,7 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
return 0;
err_invoke:
- if (fl->cctx->vmcount && scm_done) {
- u64 src_perms = 0;
- struct qcom_scm_vmperm dst_perms;
- u32 i;
-
- for (i = 0; i < fl->cctx->vmcount; i++)
- src_perms |= BIT(fl->cctx->vmperms[i].vmid);
-
- dst_perms.vmid = QCOM_SCM_VMID_HLOS;
- dst_perms.perm = QCOM_SCM_PERM_RWX;
- err = qcom_scm_assign_mem(fl->cctx->remote_heap->dma_addr,
- (u64)fl->cctx->remote_heap->size,
- &src_perms, &dst_perms, 1);
- if (err)
- dev_err(fl->sctx->dev, "Failed to assign memory dma_addr %pad size 0x%llx err %d\n",
- &fl->cctx->remote_heap->dma_addr, fl->cctx->remote_heap->size, err);
- }
-err_map:
- fastrpc_buf_free(fl->cctx->remote_heap);
- fl->cctx->remote_heap = NULL;
-err_name:
+ fl->cctx->audio_init_mem = false;
kfree(name);
err:
kfree(args);
@@ -2425,12 +2399,21 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
}
}
- if (domain_id == SDSP_DOMAIN_ID) {
+ if (domain_id == SDSP_DOMAIN_ID || domain_id == ADSP_DOMAIN_ID) {
struct resource res;
u64 src_perms;
err = of_reserved_mem_region_to_resource(rdev->of_node, 0, &res);
if (!err) {
+ if (domain_id == ADSP_DOMAIN_ID) {
+ data->remote_heap =
+ kzalloc_obj(*data->remote_heap, GFP_KERNEL);
+ if (!data->remote_heap)
+ return -ENOMEM;
+
+ data->remote_heap->dma_addr = res.start;
+ data->remote_heap->size = resource_size(&res);
+ }
src_perms = BIT(QCOM_SCM_VMID_HLOS);
err = qcom_scm_assign_mem(res.start, resource_size(&res), &src_perms,
@@ -2438,7 +2421,6 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
if (err)
goto err_free_data;
}
-
}
secure_dsp = !(of_property_read_bool(rdev->of_node, "qcom,non-secure-domain"));
@@ -2519,6 +2501,7 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
struct fastrpc_buf *buf, *b;
struct fastrpc_user *user;
unsigned long flags;
+ int err;
/* No invocations past this point */
spin_lock_irqsave(&cctx->lock, flags);
@@ -2536,8 +2519,22 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
list_for_each_entry_safe(buf, b, &cctx->invoke_interrupted_mmaps, node)
list_del(&buf->node);
- if (cctx->remote_heap)
- fastrpc_buf_free(cctx->remote_heap);
+ if (cctx->remote_heap && cctx->vmcount) {
+ u64 src_perms = 0;
+ struct qcom_scm_vmperm dst_perms;
+
+ for (u32 i = 0; i < cctx->vmcount; i++)
+ src_perms |= BIT(cctx->vmperms[i].vmid);
+
+ dst_perms.vmid = QCOM_SCM_VMID_HLOS;
+ dst_perms.perm = QCOM_SCM_PERM_RWX;
+
+ err = qcom_scm_assign_mem(cctx->remote_heap->dma_addr,
+ cctx->remote_heap->size, &src_perms,
+ &dst_perms, 1);
+ if (!err)
+ kfree(cctx->remote_heap);
+ }
of_platform_depopulate(&rpdev->dev);
--
2.43.0