| Message ID | 20240608014027.1118686-1-zhouzhouyi@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | init/Kconfig: lower to GCC version 9 check for -Warray-bounds | expand |
the patch is incorrect On Sat, Jun 8, 2024 at 9:40 AM Zhouyi Zhou <zhouzhouyi@gmail.com> wrote: > > commit 3e00f5802fab ("init/Kconfig: lower GCC version check for -Warray-bounds") > lowers GCC version check for -Warray-bounds, but I continue to see false positives > from -Warray-bounds in GCC 9.4. They are not false positives, GCC 9.4.0 did report the out of bound array access! > > This happens after > commit b44759705f7d ("bitmap: make bitmap_{get,set}_value8() use bitmap_{read,write}()") > > During the rcuturture test in Ubuntu 20.04 GCC 9.4.0 x86_64, the compiling of rcutorture test > drivers/gpio/gpio-pca953x.c issues following warning: > > ``` > CC drivers/gpio/gpio-pca953x.o > In file included from drivers/gpio/gpio-pca953x.c:12: > drivers/gpio/gpio-pca953x.c: In function ‘pca953x_probe’: > ./include/linux/bitmap.h:799:17: error: array subscript [1, 1024] is outside array bounds of ‘long unsigned int[1]’ [-Werror=array-bounds] > 799 | map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits); > | ^~ > In file included from ./include/linux/atomic.h:5, > from drivers/gpio/gpio-pca953x.c:11: > drivers/gpio/gpio-pca953x.c:1015:17: note: while referencing ‘val’ > 1015 | DECLARE_BITMAP(val, MAX_LINE); > | ^~~ > ./include/linux/types.h:11:16: note: in definition of macro ‘DECLARE_BITMAP’ > 11 | unsigned long name[BITS_TO_LONGS(bits)] > | ^~~~ > In file included from drivers/gpio/gpio-pca953x.c:12: > ./include/linux/bitmap.h:800:17: error: array subscript [1, 1024] is outside array bounds of ‘long unsigned int[1]’ [-Werror=array-bounds] > 800 | map[index + 1] |= (value >> space); > | ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~ > In file included from ./include/linux/atomic.h:5, > from drivers/gpio/gpio-pca953x.c:11: > drivers/gpio/gpio-pca953x.c:1015:17: note: while referencing ‘val’ > 1015 | DECLARE_BITMAP(val, MAX_LINE); > | ^~~ > ./include/linux/types.h:11:16: note: in definition of macro ‘DECLARE_BITMAP’ > 11 | unsigned long name[BITS_TO_LONGS(bits)] > ``` > In device_pca957x_init: ``` DECLARE_BITMAP(val, MAX_LINE); for (i = 0; i < NBANK(chip); i++) bitmap_set_value8(val, 0x02, i * BANK_SZ); ``` We can't ensure "i*BANK_SZ" is within "MAX_LINE". After setting the boundary, GCC no longer emits warnings: diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 77a2812f2974..e40bbd7c83ec 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -1021,7 +1021,7 @@ static int device_pca957x_init(struct pca953x_chip *chip) return ret; /* To enable register 6, 7 to control pull up and pull down */ - for (i = 0; i < NBANK(chip); i++) + for (i = 0; i < NBANK(chip) && i < MAX_BANK; i++) bitmap_set_value8(val, 0x02, i * BANK_SZ); The case is similar in drivers/pinctrl/pinctrl-cy8c95x0.c. I will send another patch to set array access boundaries in the above two source files. Sorry for the inconvenience that I brought, Sorry for the trouble. Regards Zhouyi > Disable gcc-9+ array-bounds avoid above warning. > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > --- > init/Kconfig | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/init/Kconfig b/init/Kconfig > index 72404c1f2157..27ce2ded95b6 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -876,14 +876,14 @@ config CC_IMPLICIT_FALLTHROUGH > default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) > default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) > > -# Currently, disable gcc-10+ array-bounds globally. > +# Currently, disable gcc-9+ array-bounds globally. > # It's still broken in gcc-13, so no upper bound yet. > -config GCC10_NO_ARRAY_BOUNDS > +config GCC9_NO_ARRAY_BOUNDS > def_bool y > > config CC_NO_ARRAY_BOUNDS > bool > - default y if CC_IS_GCC && GCC_VERSION >= 100000 && GCC10_NO_ARRAY_BOUNDS > + default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC9_NO_ARRAY_BOUNDS > > # Currently, disable -Wstringop-overflow for GCC globally. > config GCC_NO_STRINGOP_OVERFLOW > -- > 2.25.1 >
diff --git a/init/Kconfig b/init/Kconfig index 72404c1f2157..27ce2ded95b6 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -876,14 +876,14 @@ config CC_IMPLICIT_FALLTHROUGH default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) -# Currently, disable gcc-10+ array-bounds globally. +# Currently, disable gcc-9+ array-bounds globally. # It's still broken in gcc-13, so no upper bound yet. -config GCC10_NO_ARRAY_BOUNDS +config GCC9_NO_ARRAY_BOUNDS def_bool y config CC_NO_ARRAY_BOUNDS bool - default y if CC_IS_GCC && GCC_VERSION >= 100000 && GCC10_NO_ARRAY_BOUNDS + default y if CC_IS_GCC && GCC_VERSION >= 90000 && GCC9_NO_ARRAY_BOUNDS # Currently, disable -Wstringop-overflow for GCC globally. config GCC_NO_STRINGOP_OVERFLOW
commit 3e00f5802fab ("init/Kconfig: lower GCC version check for -Warray-bounds") lowers GCC version check for -Warray-bounds, but I continue to see false positives from -Warray-bounds in GCC 9.4. This happens after commit b44759705f7d ("bitmap: make bitmap_{get,set}_value8() use bitmap_{read,write}()") During the rcuturture test in Ubuntu 20.04 GCC 9.4.0 x86_64, the compiling of drivers/gpio/gpio-pca953x.c issues following warning: ``` CC drivers/gpio/gpio-pca953x.o In file included from drivers/gpio/gpio-pca953x.c:12: drivers/gpio/gpio-pca953x.c: In function ‘pca953x_probe’: ./include/linux/bitmap.h:799:17: error: array subscript [1, 1024] is outside array bounds of ‘long unsigned int[1]’ [-Werror=array-bounds] 799 | map[index + 1] &= BITMAP_FIRST_WORD_MASK(start + nbits); | ^~ In file included from ./include/linux/atomic.h:5, from drivers/gpio/gpio-pca953x.c:11: drivers/gpio/gpio-pca953x.c:1015:17: note: while referencing ‘val’ 1015 | DECLARE_BITMAP(val, MAX_LINE); | ^~~ ./include/linux/types.h:11:16: note: in definition of macro ‘DECLARE_BITMAP’ 11 | unsigned long name[BITS_TO_LONGS(bits)] | ^~~~ In file included from drivers/gpio/gpio-pca953x.c:12: ./include/linux/bitmap.h:800:17: error: array subscript [1, 1024] is outside array bounds of ‘long unsigned int[1]’ [-Werror=array-bounds] 800 | map[index + 1] |= (value >> space); | ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~ In file included from ./include/linux/atomic.h:5, from drivers/gpio/gpio-pca953x.c:11: drivers/gpio/gpio-pca953x.c:1015:17: note: while referencing ‘val’ 1015 | DECLARE_BITMAP(val, MAX_LINE); | ^~~ ./include/linux/types.h:11:16: note: in definition of macro ‘DECLARE_BITMAP’ 11 | unsigned long name[BITS_TO_LONGS(bits)] ``` Disable gcc-9+ array-bounds avoid above warning. Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> --- init/Kconfig | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)