From: Chen Zhongjin chenzhongjin@huawei.com
[ Upstream commit 18e126e97c961f7a93823795c879d7c085fe5098 ]
KASAN reported a null-ptr-deref error:
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 1373 Comm: modprobe Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:dmi_sysfs_entry_release ... Call Trace: <TASK> kobject_put dmi_sysfs_register_handle (drivers/firmware/dmi-sysfs.c:540) dmi_sysfs dmi_decode_table (drivers/firmware/dmi_scan.c:133) dmi_walk (drivers/firmware/dmi_scan.c:1115) dmi_sysfs_init (drivers/firmware/dmi-sysfs.c:149) dmi_sysfs do_one_initcall (init/main.c:1296) ... Kernel panic - not syncing: Fatal exception Kernel Offset: 0x4000000 from 0xffffffff81000000 ---[ end Kernel panic - not syncing: Fatal exception ]---
It is because previous patch added kobject_put() to release the memory which will call dmi_sysfs_entry_release() and list_del().
However, list_add_tail(entry->list) is called after the error block, so the list_head is uninitialized and cannot be deleted.
Move error handling to after list_add_tail to fix this.
Fixes: 660ba678f999 ("firmware: dmi-sysfs: Fix memory leak in dmi_sysfs_register_handle") Signed-off-by: Chen Zhongjin chenzhongjin@huawei.com Link: https://lore.kernel.org/r/20221111015326.251650-2-chenzhongjin@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/dmi-sysfs.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c index 4a93fb490cb46..3d57b08320df9 100644 --- a/drivers/firmware/dmi-sysfs.c +++ b/drivers/firmware/dmi-sysfs.c @@ -602,16 +602,16 @@ static void __init dmi_sysfs_register_handle(const struct dmi_header *dh, *ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL, "%d-%d", dh->type, entry->instance);
- if (*ret) { - kobject_put(&entry->kobj); - return; - } - /* Thread on the global list for cleanup */ spin_lock(&entry_list_lock); list_add_tail(&entry->list, &entry_list); spin_unlock(&entry_list_lock);
+ if (*ret) { + kobject_put(&entry->kobj); + return; + } + /* Handle specializations by type */ switch (dh->type) { case DMI_ENTRY_SYSTEM_EVENT_LOG: