Messages in this thread | | | Date | Wed, 10 Nov 2010 08:14:51 -0800 | From | Darren Hart <> | Subject | Re: [tip:core/urgent] futex: Address compiler warnings in exit_robust_list |
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On 11/10/2010 04:30 AM, tip-bot for Darren Hart wrote: > Commit-ID: 4c115e951d80aff126468adaec7a6c7854f61ab8 > Gitweb: http://git.kernel.org/tip/4c115e951d80aff126468adaec7a6c7854f61ab8 > Author: Darren Hart<dvhart@linux.intel.com> > AuthorDate: Thu, 4 Nov 2010 15:00:00 -0400 > Committer: Thomas Gleixner<tglx@linutronix.de> > CommitDate: Wed, 10 Nov 2010 13:27:50 +0100 > > futex: Address compiler warnings in exit_robust_list > > Since commit 1dcc41bb (futex: Change 3rd arg of fetch_robust_entry() > to unsigned int*) some gcc versions decided to emit the following > warning: > > kernel/futex.c: In function ‘exit_robust_list’: > kernel/futex.c:2492: warning: ‘next_pi’ may be used uninitialized in this function > > The commit did not introduce the warning as gcc should have warned > before that commit as well. It's just gcc being silly.
I agree that it should not have - but I did the bisect and this is the patch where the warning was first observed. I agree that it is still gcc being silly, and I don't know why it treats uninitialized ints different than uninitialized unsigned ints (or why it thinks this value is every used uninitialized for that matter).
Thanks for catching the compat-futex.c
-- Darren
> > The code path really can't result in next_pi being unitialized (or > should not), but let's keep the build clean. Annotate next_pi as an > uninitialized_var. > > [ tglx: Addressed the same issue in futex_compat.c and massaged the > changelog ] > > Signed-off-by: Darren Hart<dvhart@linux.intel.com> > Tested-by: Matt Fleming<matt@console-pimps.org> > Tested-by: Uwe Kleine-König<u.kleine-koenig@pengutronix.de> > Cc: Peter Zijlstra<peterz@infradead.org> > Cc: Eric Dumazet<eric.dumazet@gmail.com> > Cc: John Kacur<jkacur@redhat.com> > Cc: Ingo Molnar<mingo@elte.hu> > LKML-Reference:<1288897200-13008-1-git-send-email-dvhart@linux.intel.com> > Signed-off-by: Thomas Gleixner<tglx@linutronix.de> > --- > kernel/futex.c | 3 ++- > kernel/futex_compat.c | 3 ++- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/kernel/futex.c b/kernel/futex.c > index 6c683b3..40a8777 100644 > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -2489,7 +2489,8 @@ void exit_robust_list(struct task_struct *curr) > { > struct robust_list_head __user *head = curr->robust_list; > struct robust_list __user *entry, *next_entry, *pending; > - unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip; > + unsigned int limit = ROBUST_LIST_LIMIT, pi, pip; > + unsigned int uninitialized_var(next_pi); > unsigned long futex_offset; > int rc; > > diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c > index 06da4df..a7934ac 100644 > --- a/kernel/futex_compat.c > +++ b/kernel/futex_compat.c > @@ -49,7 +49,8 @@ void compat_exit_robust_list(struct task_struct *curr) > { > struct compat_robust_list_head __user *head = curr->compat_robust_list; > struct robust_list __user *entry, *next_entry, *pending; > - unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip; > + unsigned int limit = ROBUST_LIST_LIMIT, pi, pip; > + unsigned int uninitialized_var(next_pi); > compat_uptr_t uentry, next_uentry, upending; > compat_long_t futex_offset; > int rc;
-- Darren Hart Embedded Linux Kernel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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