usb: gadget: configfs: Fix use-after-free issue with udc_name
commit 64e6bbff upstream. There is a use-after-free issue, if access udc_name in function gadget_dev_desc_UDC_store after another context free udc_name in function unregister_gadget. Context 1: gadget_dev_desc_UDC_store()->unregister_gadget()-> free udc_name->set udc_name to NULL Context 2: gadget_dev_desc_UDC_show()-> access udc_name Call trace: dump_backtrace+0x0/0x340 show_stack+0x14/0x1c dump_stack+0xe4/0x134 print_address_description+0x78/0x478 __kasan_report+0x270/0x2ec kasan_report+0x10/0x18 __asan_report_load1_noabort+0x18/0x20 string+0xf4/0x138 vsnprintf+0x428/0x14d0 sprintf+0xe4/0x12c gadget_dev_desc_UDC_show+0x54/0x64 configfs_read_file+0x210/0x3a0 __vfs_read+0xf0/0x49c vfs_read+0x130/0x2b4 SyS_read+0x114/0x208 el0_svc_naked+0x34/0x38 Add mutex_lock to protect this kind of scenario. Signed-off-by: Eddie Hung <eddie.hung@mediatek.com> Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com> Reviewed-by: Peter Chen <peter.chen@nxp.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1609239215-21819-1-git-send-email-macpaul.lin@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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