| Message ID | 20180216152807.1629038-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
Hi Arnd, On Fri, Feb 16, 2018 at 4:27 PM, Arnd Bergmann <arnd@arndb.de> wrote: > When we build this driver with on x86-32, gcc produces a false-positive warning: > > drivers/clk/renesas/clk-sh73a0.c: In function 'sh73a0_cpg_clocks_init': > drivers/clk/renesas/clk-sh73a0.c:155:10: error: 'parent_name' may be used uninitialized in this function [-Werror=maybe-uninitialized] > return clk_register_fixed_factor(NULL, name, parent_name, 0, > > We can work around that warning by adding a fake initialization, I tried > and failed to come up with any better workaround. This is currently one > of few remaining warnings for a 4.14.y randconfig build, so it would be > good to also have it backported at least to that version. Older versions > have more randconfig warnings, so we might not care. > > I had not noticed this earlier, because one patch in my randconfig test > tree removes the '-ffreestanding' option on x86-32, and that avoids > the warning. The -ffreestanding flag was originally global but moved > into arch/i386 by Andi Kleen in commit 6edfba1b33c7 ("[PATCH] x86_64: > Don't define string functions to builtin") as a 'temporary workaround'. > > Like many temporary hacks, this turned out to be rather long-lived, from > all I can tell we still need a simple fix to asm/string_32.h before it > can be removed, but I'm not sure about how to best do that. > > Cc: stable@vger.kernel.org > Cc: Andi Kleen <ak@linux.intel.com> > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks, this is a known false positive. Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > drivers/clk/renesas/clk-sh73a0.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/clk/renesas/clk-sh73a0.c b/drivers/clk/renesas/clk-sh73a0.c > index eea38f6ea77e..3892346c4fcc 100644 > --- a/drivers/clk/renesas/clk-sh73a0.c > +++ b/drivers/clk/renesas/clk-sh73a0.c > @@ -46,7 +46,7 @@ struct div4_clk { > unsigned int shift; > }; > > -static struct div4_clk div4_clks[] = { > +static const struct div4_clk div4_clks[] = { This change is not part of the fix... > { "zg", "pll0", CPG_FRQCRA, 16 }, > { "m3", "pll1", CPG_FRQCRA, 12 }, > { "b", "pll1", CPG_FRQCRA, 8 }, > @@ -79,7 +79,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, > { > const struct clk_div_table *table = NULL; > unsigned int shift, reg, width; > - const char *parent_name; > + const char *parent_name = NULL; > unsigned int mult = 1; > unsigned int div = 1; > > @@ -135,7 +135,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, > shift = 24; > width = 5; > } else { > - struct div4_clk *c; > + const struct div4_clk *c; ... and neither is this one. > > for (c = div4_clks; c->name; c++) { > if (!strcmp(name, c->name)) { Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Quoting Arnd Bergmann (2018-02-16 07:27:47) > When we build this driver with on x86-32, gcc produces a false-positive warning: > > drivers/clk/renesas/clk-sh73a0.c: In function 'sh73a0_cpg_clocks_init': > drivers/clk/renesas/clk-sh73a0.c:155:10: error: 'parent_name' may be used uninitialized in this function [-Werror=maybe-uninitialized] > return clk_register_fixed_factor(NULL, name, parent_name, 0, > > We can work around that warning by adding a fake initialization, I tried > and failed to come up with any better workaround. This is currently one > of few remaining warnings for a 4.14.y randconfig build, so it would be > good to also have it backported at least to that version. Older versions > have more randconfig warnings, so we might not care. > > I had not noticed this earlier, because one patch in my randconfig test > tree removes the '-ffreestanding' option on x86-32, and that avoids > the warning. The -ffreestanding flag was originally global but moved > into arch/i386 by Andi Kleen in commit 6edfba1b33c7 ("[PATCH] x86_64: > Don't define string functions to builtin") as a 'temporary workaround'. > > Like many temporary hacks, this turned out to be rather long-lived, from > all I can tell we still need a simple fix to asm/string_32.h before it > can be removed, but I'm not sure about how to best do that. > > Cc: stable@vger.kernel.org > Cc: Andi Kleen <ak@linux.intel.com> > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- Applied to clk-next
diff --git a/drivers/clk/renesas/clk-sh73a0.c b/drivers/clk/renesas/clk-sh73a0.c index eea38f6ea77e..3892346c4fcc 100644 --- a/drivers/clk/renesas/clk-sh73a0.c +++ b/drivers/clk/renesas/clk-sh73a0.c @@ -46,7 +46,7 @@ struct div4_clk { unsigned int shift; }; -static struct div4_clk div4_clks[] = { +static const struct div4_clk div4_clks[] = { { "zg", "pll0", CPG_FRQCRA, 16 }, { "m3", "pll1", CPG_FRQCRA, 12 }, { "b", "pll1", CPG_FRQCRA, 8 }, @@ -79,7 +79,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, { const struct clk_div_table *table = NULL; unsigned int shift, reg, width; - const char *parent_name; + const char *parent_name = NULL; unsigned int mult = 1; unsigned int div = 1; @@ -135,7 +135,7 @@ sh73a0_cpg_register_clock(struct device_node *np, struct sh73a0_cpg *cpg, shift = 24; width = 5; } else { - struct div4_clk *c; + const struct div4_clk *c; for (c = div4_clks; c->name; c++) { if (!strcmp(name, c->name)) {
When we build this driver with on x86-32, gcc produces a false-positive warning: drivers/clk/renesas/clk-sh73a0.c: In function 'sh73a0_cpg_clocks_init': drivers/clk/renesas/clk-sh73a0.c:155:10: error: 'parent_name' may be used uninitialized in this function [-Werror=maybe-uninitialized] return clk_register_fixed_factor(NULL, name, parent_name, 0, We can work around that warning by adding a fake initialization, I tried and failed to come up with any better workaround. This is currently one of few remaining warnings for a 4.14.y randconfig build, so it would be good to also have it backported at least to that version. Older versions have more randconfig warnings, so we might not care. I had not noticed this earlier, because one patch in my randconfig test tree removes the '-ffreestanding' option on x86-32, and that avoids the warning. The -ffreestanding flag was originally global but moved into arch/i386 by Andi Kleen in commit 6edfba1b33c7 ("[PATCH] x86_64: Don't define string functions to builtin") as a 'temporary workaround'. Like many temporary hacks, this turned out to be rather long-lived, from all I can tell we still need a simple fix to asm/string_32.h before it can be removed, but I'm not sure about how to best do that. Cc: stable@vger.kernel.org Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/clk/renesas/clk-sh73a0.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)