| Message ID | 20170927055252.12225-1-zlang@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Sep 27, 2017 at 05:52:52AM +0000, Zorro Lang wrote: > When test g/317 or g/318 on ARM server, we got a kernel exception: > > kernel: nsexec[8203]: SP Alignment exception: pc=00000000004010a0 sp=00000000005200e8 > > nsexec gives an unaligned child stack address to clone() system > call sometimes. For making sure it's always aligned, use > "__attribute__((aligned))" extension of GCC (Thanks this suggestion > from Eric sandeen). > > Signed-off-by: Zorro Lang <zlang@redhat.com> > --- > src/nsexec.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/src/nsexec.c b/src/nsexec.c > index f033b1a4..205dd081 100644 > --- a/src/nsexec.c > +++ b/src/nsexec.c > @@ -138,7 +138,8 @@ childFunc(void *arg) > > #define STACK_SIZE (1024 * 1024) > > -static char child_stack[STACK_SIZE]; /* Space for child's stack */ > +/* Space for child's stack */ > +static char __attribute__((aligned)) child_stack[STACK_SIZE]; I don't really think the comment is necessary, other than that: Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> > > int > main(int argc, char *argv[]) > -- > 2.13.5 > > -- > To unsubscribe from this list: send the line "unsubscribe fstests" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On 9/27/17 12:52 AM, Zorro Lang wrote: > When test g/317 or g/318 on ARM server, we got a kernel exception: > > kernel: nsexec[8203]: SP Alignment exception: pc=00000000004010a0 sp=00000000005200e8 > > nsexec gives an unaligned child stack address to clone() system > call sometimes. For making sure it's always aligned, use > "__attribute__((aligned))" extension of GCC (Thanks this suggestion > from Eric sandeen). > > Signed-off-by: Zorro Lang <zlang@redhat.com> > --- > src/nsexec.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/src/nsexec.c b/src/nsexec.c > index f033b1a4..205dd081 100644 > --- a/src/nsexec.c > +++ b/src/nsexec.c > @@ -138,7 +138,8 @@ childFunc(void *arg) > > #define STACK_SIZE (1024 * 1024) > > -static char child_stack[STACK_SIZE]; /* Space for child's stack */ > +/* Space for child's stack */ > +static char __attribute__((aligned)) child_stack[STACK_SIZE]; Does it matter if the __attribute__ goes before or after the array name (child_stack[])? I can't quite tell from reading i.e. https://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Variable-Attributes.html#Variable%20Attributes if it does, though most examples I see have the __attribute__ after the variable name, i.e. > short array[3] __attribute__ ((aligned)); in the URL above. -Eric > > int > main(int argc, char *argv[]) > -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Sep 29, 2017 at 09:44:05AM -0500, Eric Sandeen wrote: > On 9/27/17 12:52 AM, Zorro Lang wrote: > > When test g/317 or g/318 on ARM server, we got a kernel exception: > > > > kernel: nsexec[8203]: SP Alignment exception: pc=00000000004010a0 sp=00000000005200e8 > > > > nsexec gives an unaligned child stack address to clone() system > > call sometimes. For making sure it's always aligned, use > > "__attribute__((aligned))" extension of GCC (Thanks this suggestion > > from Eric sandeen). > > > > Signed-off-by: Zorro Lang <zlang@redhat.com> > > --- > > src/nsexec.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/src/nsexec.c b/src/nsexec.c > > index f033b1a4..205dd081 100644 > > --- a/src/nsexec.c > > +++ b/src/nsexec.c > > @@ -138,7 +138,8 @@ childFunc(void *arg) > > > > #define STACK_SIZE (1024 * 1024) > > > > -static char child_stack[STACK_SIZE]; /* Space for child's stack */ > > +/* Space for child's stack */ > > +static char __attribute__((aligned)) child_stack[STACK_SIZE]; > > Does it matter if the __attribute__ goes before or after > the array name (child_stack[])? I can't quite tell from reading i.e. > https://gcc.gnu.org/onlinedocs/gcc-3.1/gcc/Variable-Attributes.html#Variable%20Attributes > if it does, though most examples I see have the __attribute__ after the variable > name, i.e. Sorry, I didn't notice this "before/after" problem. Yes, you're right, everyone use "__attribute__" at the end. I'll change that. BTW, using it in the middle works (compile and run) fine from my side. Thanks, Zorro > > > short array[3] __attribute__ ((aligned)); > > in the URL above. > > -Eric > > > > > int > > main(int argc, char *argv[]) > > -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/src/nsexec.c b/src/nsexec.c index f033b1a4..205dd081 100644 --- a/src/nsexec.c +++ b/src/nsexec.c @@ -138,7 +138,8 @@ childFunc(void *arg) #define STACK_SIZE (1024 * 1024) -static char child_stack[STACK_SIZE]; /* Space for child's stack */ +/* Space for child's stack */ +static char __attribute__((aligned)) child_stack[STACK_SIZE]; int main(int argc, char *argv[])
When test g/317 or g/318 on ARM server, we got a kernel exception: kernel: nsexec[8203]: SP Alignment exception: pc=00000000004010a0 sp=00000000005200e8 nsexec gives an unaligned child stack address to clone() system call sometimes. For making sure it's always aligned, use "__attribute__((aligned))" extension of GCC (Thanks this suggestion from Eric sandeen). Signed-off-by: Zorro Lang <zlang@redhat.com> --- src/nsexec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)