From aa5ae06515a451d543d9ab37e2c14f97a5ba4519 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 13 Jun 2019 19:45:27 +0300 Subject: [PATCH] i2c: i801: Fix kernel crash in is_dell_system_with_lis3lv02d() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The commit 19b07cb4a187 ("i2c: i801: Register optional lis3lv02d I2C device on Dell machines") introduced a new check in order to enumerate some slave devices on Dell machines. Though, it brings a regression on machines where DMI vendor is not set. BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 8 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc4-next-20190613+ #317 RIP: 0010:strcmp+0xc/0x20 To fix this crash, check if vendor field is present before accessing to it. Fixes: 19b07cb4a187 ("i2c: i801: Register optional lis3lv02d I2C device on Dell machines") Signed-off-by: Andy Shevchenko Reviewed-by: Pali Rohár Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-i801.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index c5bdaf35cd09..7d14b6729772 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -1188,7 +1188,7 @@ static bool is_dell_system_with_lis3lv02d(void) const char *vendor; vendor = dmi_get_system_info(DMI_SYS_VENDOR); - if (strcmp(vendor, "Dell Inc.") != 0) + if (!vendor || strcmp(vendor, "Dell Inc.")) return false; /*