[PATCH 03/16] IA64: use ACCESS_ONCE for rlimits

From: Jiri Slaby
Date: Wed Nov 18 2009 - 09:52:51 EST


Make sure compiler won't do weird things with limits. E.g. fetching
them twice may return 2 different values after writable limits are
implemented.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: linux-ia64@xxxxxxxxxxxxxxx
---
arch/ia64/kernel/perfmon.c | 2 +-
arch/ia64/kernel/sys_ia64.c | 2 +-
arch/ia64/mm/init.c | 3 ++-
3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index f178270..91b8607 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -2298,7 +2298,7 @@ pfm_smpl_buffer_alloc(struct task_struct *task, struct file *filp, pfm_context_t
* if ((mm->total_vm << PAGE_SHIFT) + len> task->rlim[RLIMIT_AS].rlim_cur)
* return -ENOMEM;
*/
- if (size > task->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
+ if (size > ACCESS_ONCE(task->signal->rlim[RLIMIT_MEMLOCK].rlim_cur))
return -ENOMEM;

/*
diff --git a/arch/ia64/kernel/sys_ia64.c b/arch/ia64/kernel/sys_ia64.c
index 92ed83f..6a2b5d9 100644
--- a/arch/ia64/kernel/sys_ia64.c
+++ b/arch/ia64/kernel/sys_ia64.c
@@ -129,7 +129,7 @@ ia64_brk (unsigned long brk)
goto out;

/* Check against rlimit.. */
- rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
+ rlim = ACCESS_ONCE(current->signal->rlim[RLIMIT_DATA].rlim_cur);
if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
goto out;

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 1857766..fe6d63f 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -91,7 +91,8 @@ dma_mark_clean(void *addr, size_t size)
inline void
ia64_set_rbs_bot (void)
{
- unsigned long stack_size = current->signal->rlim[RLIMIT_STACK].rlim_max & -16;
+ unsigned long stack_size = ACCESS_ONCE(current->signal->
+ rlim[RLIMIT_STACK].rlim_max) & -16;

if (stack_size > MAX_USER_STACK_SIZE)
stack_size = MAX_USER_STACK_SIZE;
--
1.6.4.2

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