[PATCH v4] liveupdate: fix return value on session allocation failure

Pasha Tatashin
2026-04-15T19:37:40Z

When session allocation fails during deserialization, the global 'err'
variable was not updated before returning. This caused subsequent calls
to luo_session_deserialize() to incorrectly report success.

Ensure 'err' is set to the error code from PTR_ERR(session). This
ensures that an error is correctly returned to userspace when it
attempts to open /dev/liveupdate in the new kernel if deserialization
failed.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav (Google) <pratyush@kernel.org>
---
kernel/liveupdate/luo_session.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index a3327a28fc1f..7a42385dabe2 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -514,11 +514,12 @@ int luo_session_deserialize(void)
{
struct luo_session_header *sh = &luo_session_global.incoming;
static bool is_deserialized;
- static int err;
+ static int saved_err;
+ int err;

/* If has been deserialized, always return the same error code */
if (is_deserialized)
- return err;
+ return saved_err;

is_deserialized = true;
if (!sh->active)
@@ -547,7 +548,8 @@ int luo_session_deserialize(void)
pr_warn("Failed to allocate session [%.*s] during deserialization %pe\n",
(int)sizeof(sh->ser[i].name),
sh->ser[i].name, session);
- return PTR_ERR(session);
+ err = PTR_ERR(session);
+ goto save_err;
}

err = luo_session_insert(sh, session);
@@ -555,7 +557,7 @@ int luo_session_deserialize(void)
pr_warn("Failed to insert session [%s] %pe\n",
session->name, ERR_PTR(err));
luo_session_free(session);
- return err;
+ goto save_err;
}

scoped_guard(mutex, &session->mutex) {
@@ -565,7 +567,7 @@ int luo_session_deserialize(void)
if (err) {
pr_warn("Failed to deserialize files for session [%s] %pe\n",
session->name, ERR_PTR(err));
- return err;
+ goto save_err;
}
}

@@ -574,6 +576,9 @@ int luo_session_deserialize(void)
sh->ser = NULL;

return 0;
+save_err:
+ saved_err = err;
+ return err;
}

int luo_session_serialize(void)
--
2.43.0