From: Arnd Bergmann arnd@arndb.de
commit 14e3cdbb00a885eedc95c0cf8eda8fe28d26d6b4 upstream.
A bugfix introduce a link failure in configurations without CONFIG_MODULES:
In file included from drivers/media/usb/dvb-usb/pctv452e.c:20:0: drivers/media/usb/dvb-usb/pctv452e.c: In function 'pctv452e_frontend_attach': drivers/media/dvb-frontends/stb0899_drv.h:151:36: error: weak declaration of 'stb0899_attach' being applied to a already existing, static definition
The problem is that the !IS_REACHABLE() declaration of stb0899_attach() is a 'static inline' definition that clashes with the weak definition.
I further observed that the bugfix was only done for one of the five users of stb0899_attach(), the other four still have the problem. This reverts the bugfix and instead addresses the problem by not dropping the reference count when calling '->detach()', instead we call this function directly in dvb_frontend_put() before dropping the kref on the front-end.
I first submitted this in early 2018, and after some discussion it was apparently discarded. While there is a long-term plan in place, that plan is obviously not nearing completion yet, and the current kernel is still broken unless this patch is applied.
Link: https://patchwork.kernel.org/patch/10140175/ Link: https://patchwork.linuxtv.org/patch/54831/
Cc: Max Kellermann max.kellermann@gmail.com Cc: Wolfgang Rohdewald wolfgang@rohdewald.de Cc: stable@vger.kernel.org Fixes: f686c14364ad ("[media] stb0899: move code to "detach" callback") Fixes: 6cdeaed3b142 ("media: dvb_usb_pctv452e: module refcount changes were unbalanced") Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Sean Young sean@mess.org Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/media/dvb-core/dvb_frontend.c | 4 +++- drivers/media/usb/dvb-usb/pctv452e.c | 8 -------- 2 files changed, 3 insertions(+), 9 deletions(-)
--- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -164,6 +164,9 @@ static void dvb_frontend_free(struct kre
static void dvb_frontend_put(struct dvb_frontend *fe) { + /* call detach before dropping the reference count */ + if (fe->ops.detach) + fe->ops.detach(fe); /* * Check if the frontend was registered, as otherwise * kref was not initialized yet. @@ -3035,7 +3038,6 @@ void dvb_frontend_detach(struct dvb_fron dvb_frontend_invoke_release(fe, fe->ops.release_sec); dvb_frontend_invoke_release(fe, fe->ops.tuner_ops.release); dvb_frontend_invoke_release(fe, fe->ops.analog_ops.release); - dvb_frontend_invoke_release(fe, fe->ops.detach); dvb_frontend_put(fe); } EXPORT_SYMBOL(dvb_frontend_detach); --- a/drivers/media/usb/dvb-usb/pctv452e.c +++ b/drivers/media/usb/dvb-usb/pctv452e.c @@ -913,14 +913,6 @@ static int pctv452e_frontend_attach(stru &a->dev->i2c_adap); if (!a->fe_adap[0].fe) return -ENODEV; - - /* - * dvb_frontend will call dvb_detach for both stb0899_detach - * and stb0899_release but we only do dvb_attach(stb0899_attach). - * Increment the module refcount instead. - */ - symbol_get(stb0899_attach); - if ((dvb_attach(lnbp22_attach, a->fe_adap[0].fe, &a->dev->i2c_adap)) == NULL) err("Cannot attach lnbp22\n");