diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-09-15 22:45:43 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-21 10:35:04 +0100 |
| commit | 002cc9ee358bfeb21490830b6ba34ba217ef22eb (patch) | |
| tree | ada846dc3b566d993086a7713462541fd996814e /include | |
| parent | 1354c2fa639636e3b83a736fb29eb449477c64f9 (diff) | |
sched/core: Add try_get_task_stack() and put_task_stack()
commit c6c314a613cd7d03fb97713e0d642b493de42e69 upstream.
There are a few places in the kernel that access stack memory
belonging to a different task. Before we can start freeing task
stacks before the task_struct is freed, we need a way for those code
paths to pin the stack.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/17a434f50ad3d77000104f21666575e10a9c1fbd.1474003868.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index d6b2e77aad3f..761247c966a5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2858,11 +2858,19 @@ static inline struct thread_info *task_thread_info(struct task_struct *task) { return &task->thread_info; } + +/* + * When accessing the stack of a non-current task that might exit, use + * try_get_task_stack() instead. task_stack_page will return a pointer + * that could get freed out from under you. + */ static inline void *task_stack_page(const struct task_struct *task) { return task->stack; } + #define setup_thread_stack(new,old) do { } while(0) + static inline unsigned long *end_of_stack(const struct task_struct *task) { return task->stack; @@ -2898,6 +2906,14 @@ static inline unsigned long *end_of_stack(struct task_struct *p) } #endif + +static inline void *try_get_task_stack(struct task_struct *tsk) +{ + return task_stack_page(tsk); +} + +static inline void put_task_stack(struct task_struct *tsk) {} + #define task_stack_end_corrupted(task) \ (*(end_of_stack(task)) != STACK_END_MAGIC) |