From acb40d8412572b2a79216a98acdbac10e620da1b Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Mon, 9 Oct 2017 16:22:34 +0300 Subject: [PATCH] thunderbolt: Initialize Thunderbolt bus earlier The 0day kbuild robot reports following crash: BUG: unable to handle kernel NULL pointer dereference at 00000004 IP: tb_property_find+0xe/0x41 *pde = 00000000 Oops: 0000 [#1] CPU: 0 PID: 1 Comm: swapper Not tainted 4.14.0-rc1-00741-ge69b6c0 #412 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 task: 89c80000 task.stack: 89c7c000 EIP: tb_property_find+0xe/0x41 EFLAGS: 00210246 CPU: 0 EAX: 00000000 EBX: 7a368f47 ECX: 00000044 EDX: 7a368f47 ESI: 8851d340 EDI: 7a368f47 EBP: 89c7df0c ESP: 89c7defc DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 CR0: 80050033 CR2: 00000004 CR3: 027a2000 CR4: 00000690 Call Trace: tb_register_property_dir+0x49/0xb9 ? cdc_mbim_driver_init+0x1b/0x1b tbnet_init+0x77/0x9f ? cdc_mbim_driver_init+0x1b/0x1b do_one_initcall+0x7e/0x145 ? parse_args+0x10c/0x1b3 ? kernel_init_freeable+0xbe/0x159 kernel_init_freeable+0xd1/0x159 ? rest_init+0x110/0x110 kernel_init+0xd/0xd0 ret_from_fork+0x19/0x30 The reason is that both Thunderbolt bus and thunderbolt-net are build into the kernel image, and the latter is linked first because drivers/net comes before drivers/thunderbolt. Since both use module_init() thunderbolt-net ends up calling Thunderbolt bus functions too early triggering the above crash. Fix this by moving Thunderbolt bus initialization to happen earlier to make sure all the data structures are ready when Thunderbolt service drivers are initialized. To be on the safe side also add a check for properly initialized xdomain_property_dir to tb_register_property_dir(). Reported-by: kernel test robot Signed-off-by: Mika Westerberg Signed-off-by: David S. Miller --- drivers/thunderbolt/nhi.c | 2 +- drivers/thunderbolt/xdomain.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c index 0e79eebfcbb7..419a7a90bce0 100644 --- a/drivers/thunderbolt/nhi.c +++ b/drivers/thunderbolt/nhi.c @@ -1144,5 +1144,5 @@ static void __exit nhi_unload(void) tb_domain_exit(); } -module_init(nhi_init); +fs_initcall(nhi_init); module_exit(nhi_unload); diff --git a/drivers/thunderbolt/xdomain.c b/drivers/thunderbolt/xdomain.c index f2d06f6f7be9..138027537d29 100644 --- a/drivers/thunderbolt/xdomain.c +++ b/drivers/thunderbolt/xdomain.c @@ -1487,6 +1487,9 @@ int tb_register_property_dir(const char *key, struct tb_property_dir *dir) { int ret; + if (WARN_ON(!xdomain_property_dir)) + return -EAGAIN; + if (!key || strlen(key) > 8) return -EINVAL; -- 2.30.2