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Date: Tue, 22 Feb 2022 21:27:00 -0000
From: "tip-bot2 for Sebastian Andrzej Siewior" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Thomas Gleixner <tglx@...utronix.de>,
Andy Lutomirski <luto@...nel.org>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: core/core] fork: Don't assign the stack pointer in dup_task_struct()
The following commit has been merged into the core/core branch of tip:
Commit-ID: 7865aba3ade4cf30f0ac08e015550084a50d9afb
Gitweb: https://git.kernel.org/tip/7865aba3ade4cf30f0ac08e015550084a50d9afb
Author: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Thu, 17 Feb 2022 11:24:02 +01:00
Committer: Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Tue, 22 Feb 2022 22:25:01 +01:00
fork: Don't assign the stack pointer in dup_task_struct()
All four versions of alloc_thread_stack_node() assign now
task_struct::stack in case the allocation was successful.
Let alloc_thread_stack_node() return an error code instead of the stack
pointer and remove the stack assignment in dup_task_struct().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Andy Lutomirski <luto@...nel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-5-bigeasy@linutronix.de
---
kernel/fork.c | 47 ++++++++++++++++-------------------------------
1 file changed, 16 insertions(+), 31 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index 7b70c47..875bd43 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -211,7 +211,7 @@ static int free_vm_stack_cache(unsigned int cpu)
return 0;
}
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
void *stack;
int i;
@@ -232,7 +232,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
tsk->stack_vm_area = s;
tsk->stack = s->addr;
- return s->addr;
+ return 0;
}
/*
@@ -245,17 +245,16 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
THREADINFO_GFP & ~__GFP_ACCOUNT,
PAGE_KERNEL,
0, node, __builtin_return_address(0));
-
+ if (!stack)
+ return -ENOMEM;
/*
* We can't call find_vm_area() in interrupt context, and
* free_thread_stack() can be called in interrupt context,
* so cache the vm_struct.
*/
- if (stack) {
- tsk->stack_vm_area = find_vm_area(stack);
- tsk->stack = stack;
- }
- return stack;
+ tsk->stack_vm_area = find_vm_area(stack);
+ tsk->stack = stack;
+ return 0;
}
static void free_thread_stack(struct task_struct *tsk)
@@ -282,16 +281,16 @@ static void free_thread_stack(struct task_struct *tsk)
# else /* !CONFIG_VMAP_STACK */
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
struct page *page = alloc_pages_node(node, THREADINFO_GFP,
THREAD_SIZE_ORDER);
if (likely(page)) {
tsk->stack = kasan_reset_tag(page_address(page));
- return tsk->stack;
+ return 0;
}
- return NULL;
+ return -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
@@ -305,14 +304,13 @@ static void free_thread_stack(struct task_struct *tsk)
static struct kmem_cache *thread_stack_cache;
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk,
- int node)
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
unsigned long *stack;
stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node);
stack = kasan_reset_tag(stack);
tsk->stack = stack;
- return stack;
+ return stack ? 0 : -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
@@ -332,13 +330,13 @@ void thread_stack_cache_init(void)
# endif /* THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) */
#else /* CONFIG_ARCH_THREAD_STACK_ALLOCATOR */
-static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
+static int alloc_thread_stack_node(struct task_struct *tsk, int node)
{
unsigned long *stack;
stack = arch_alloc_thread_stack_node(tsk, node);
tsk->stack = stack;
- return stack;
+ return stack ? 0 : -ENOMEM;
}
static void free_thread_stack(struct task_struct *tsk)
@@ -895,8 +893,6 @@ void set_task_stack_end_magic(struct task_struct *tsk)
static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
struct task_struct *tsk;
- unsigned long *stack;
- struct vm_struct *stack_vm_area __maybe_unused;
int err;
if (node == NUMA_NO_NODE)
@@ -909,24 +905,13 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
if (err)
goto free_tsk;
- stack = alloc_thread_stack_node(tsk, node);
- if (!stack)
+ err = alloc_thread_stack_node(tsk, node);
+ if (err)
goto free_tsk;
if (memcg_charge_kernel_stack(tsk))
goto free_stack;
- stack_vm_area = task_stack_vm_area(tsk);
-
- /*
- * arch_dup_task_struct() clobbers the stack-related fields. Make
- * sure they're properly initialized before using any stack-related
- * functions again.
- */
- tsk->stack = stack;
-#ifdef CONFIG_VMAP_STACK
- tsk->stack_vm_area = stack_vm_area;
-#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
refcount_set(&tsk->stack_refcount, 1);
#endif
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