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@xxxxxxxxxxxxxxx> AuthorDate: Thu, 4 Nov 2010 15:00:00 -0400 Committer: Thomas Gleixner<tglx@xxxxxxxxxxxxx> 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 âexit_robust_listâ: kernel/futex.c:2492: warning: ânext_piâ 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@xxxxxxxxxxxxxxx> Tested-by: Matt Fleming<matt@xxxxxxxxxxxxxxxxx> Tested-by: Uwe Kleine-KÃnig<u.kleine-koenig@xxxxxxxxxxxxxx> Cc: Peter Zijlstra<peterz@xxxxxxxxxxxxx> Cc: Eric Dumazet<eric.dumazet@xxxxxxxxx> Cc: John Kacur<jkacur@xxxxxxxxxx> Cc: Ingo Molnar<mingo@xxxxxxx> LKML-Reference:<1288897200-13008-1-git-send-email-dvhart@xxxxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner<tglx@xxxxxxxxxxxxx> --- 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-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html