7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lorenzo Stoakes (ARM) commit feade898fc958ff355101adf12d5632272e64220 upstream. fb_deferred_io_init() allocates deferred I/O state, populating info->fbdefio_state, or leaving it NULL if an error occurs. Currently picolcd_init_framebuffer() ignores its return value. Therefore if an error arises in fb_deferred_io_init() (for instance, due to an allocation failure) info->fbdefio_state is left NULL. When the file is subsequently opened, fb_open() will dereference a NULL pointer (calling fb_deferred_io_open()). Fix this by checking for the error. Also correct cleanup ordering - defio is initialised after the sysfs file, so cleanup defio first. Fixes: 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct") Cc: stable@vger.kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman --- drivers/hid/hid-picolcd_fb.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/drivers/hid/hid-picolcd_fb.c +++ b/drivers/hid/hid-picolcd_fb.c @@ -531,17 +531,23 @@ int picolcd_init_framebuffer(struct pico goto err_cleanup; } - fb_deferred_io_init(info); + error = fb_deferred_io_init(info); + if (error) { + dev_err(dev, "failed to initialize deferred I/O\n"); + goto err_sysfs; + } + error = register_framebuffer(info); if (error) { dev_err(dev, "failed to register framebuffer\n"); - goto err_sysfs; + goto err_defio; } return 0; +err_defio: + fb_deferred_io_cleanup(info); err_sysfs: device_remove_file(dev, &dev_attr_fb_update_rate); - fb_deferred_io_cleanup(info); err_cleanup: data->fb_info = NULL;