| Message ID | 20200620033007.1444705-12-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | Remove uninitialized_var() macro | expand |
On Fri, Jun 19, 2020 at 8:30 PM Kees Cook <keescook@chromium.org> wrote: > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > (or can in the future), and suppresses unrelated compiler warnings (e.g. > "unused variable"). If the compiler thinks it is uninitialized, either > simply initialize the variable or make compiler changes. As a precursor > to removing[2] this[3] macro[4], just remove this variable since it was > actually unused: > > drivers/input/touchscreen/sur40.c:459:6: warning: variable 'packet_id' set but not used [-Wunused-but-set-variable] > 459 | u32 packet_id; > | ^~~~~~~~~ > > However, in keeping with the documentation desires outlined in commit > 335abaea7a27 ("Input: sur40 - silence unnecessary noisy debug output"), > comment out the assignment instead of removing it. > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > Fixes: 335abaea7a27 ("Input: sur40 - silence unnecessary noisy debug output") Probably should comment out `/* u32 packet_id */` rather than removing it then, but that doesn't really matter. Either way, Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > drivers/input/touchscreen/sur40.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c > index 34d31c7ec8ba..620cdd7d214a 100644 > --- a/drivers/input/touchscreen/sur40.c > +++ b/drivers/input/touchscreen/sur40.c > @@ -456,8 +456,6 @@ static void sur40_poll(struct input_dev *input) > { > struct sur40_state *sur40 = input_get_drvdata(input); > int result, bulk_read, need_blobs, packet_blobs, i; > - u32 uninitialized_var(packet_id); > - > struct sur40_header *header = &sur40->bulk_in_buffer->header; > struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0]; > > @@ -491,7 +489,7 @@ static void sur40_poll(struct input_dev *input) > if (need_blobs == -1) { > need_blobs = le16_to_cpu(header->count); > dev_dbg(sur40->dev, "need %d blobs\n", need_blobs); > - packet_id = le32_to_cpu(header->packet_id); > + /* packet_id = le32_to_cpu(header->packet_id); */ > } > > /* > -- > 2.25.1 > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20200620033007.1444705-12-keescook%40chromium.org.
diff --git a/drivers/input/touchscreen/sur40.c b/drivers/input/touchscreen/sur40.c index 34d31c7ec8ba..620cdd7d214a 100644 --- a/drivers/input/touchscreen/sur40.c +++ b/drivers/input/touchscreen/sur40.c @@ -456,8 +456,6 @@ static void sur40_poll(struct input_dev *input) { struct sur40_state *sur40 = input_get_drvdata(input); int result, bulk_read, need_blobs, packet_blobs, i; - u32 uninitialized_var(packet_id); - struct sur40_header *header = &sur40->bulk_in_buffer->header; struct sur40_blob *inblob = &sur40->bulk_in_buffer->blobs[0]; @@ -491,7 +489,7 @@ static void sur40_poll(struct input_dev *input) if (need_blobs == -1) { need_blobs = le16_to_cpu(header->count); dev_dbg(sur40->dev, "need %d blobs\n", need_blobs); - packet_id = le32_to_cpu(header->packet_id); + /* packet_id = le32_to_cpu(header->packet_id); */ } /*
Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. As a precursor to removing[2] this[3] macro[4], just remove this variable since it was actually unused: drivers/input/touchscreen/sur40.c:459:6: warning: variable 'packet_id' set but not used [-Wunused-but-set-variable] 459 | u32 packet_id; | ^~~~~~~~~ However, in keeping with the documentation desires outlined in commit 335abaea7a27 ("Input: sur40 - silence unnecessary noisy debug output"), comment out the assignment instead of removing it. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Fixes: 335abaea7a27 ("Input: sur40 - silence unnecessary noisy debug output") Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/input/touchscreen/sur40.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)