From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 30 Apr 2019 04:18:40 -0700 Sender: tip tree robot From: tip-bot for Nadav Amit Message-ID: In-Reply-To: <20190426001143.4983-6-namit@vmware.com> References: <20190426001143.4983-6-namit@vmware.com> Subject: [tip:x86/mm] fork: Provide a function for copying init_mm MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline To: linux-tip-commits@vger.kernel.org Cc: peterz@infradead.org, luto@kernel.org, mhiramat@kernel.org, kristen@linux.intel.com, linux-kernel@vger.kernel.org, hpa@zytor.com, deneen.t.dock@intel.com, namit@vmware.com, tglx@linutronix.de, torvalds@linux-foundation.org, dave.hansen@intel.com, mingo@kernel.org, linux_dti@icloud.com, kernel-hardening@lists.openwall.com, will.deacon@arm.com, rick.p.edgecombe@intel.com, riel@surriel.com, keescook@chromium.org, akpm@linux-foundation.org, bp@alien8.de, ard.biesheuvel@linaro.org List-ID: Commit-ID: 13585fa0668c724efab9635aaeef6ec390217415 Gitweb: https://git.kernel.org/tip/13585fa0668c724efab9635aaeef6ec390217415 Author: Nadav Amit AuthorDate: Thu, 25 Apr 2019 17:11:25 -0700 Committer: Ingo Molnar CommitDate: Tue, 30 Apr 2019 12:37:51 +0200 fork: Provide a function for copying init_mm Provide a function for copying init_mm. This function will be later used for setting a temporary mm. Tested-by: Masami Hiramatsu Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Masami Hiramatsu Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Rik van Riel Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190426001143.4983-6-namit@vmware.com Signed-off-by: Ingo Molnar --- include/linux/sched/task.h | 1 + kernel/fork.c | 24 ++++++++++++++++++------ 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 2e97a2227045..f1227f2c38a4 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -76,6 +76,7 @@ extern void exit_itimers(struct signal_struct *); extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long); extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); struct task_struct *fork_idle(int); +struct mm_struct *copy_init_mm(void); extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); diff --git a/kernel/fork.c b/kernel/fork.c index 44fba5e5e916..fbe9dfcd8680 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1299,13 +1299,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm) complete_vfork_done(tsk); } -/* - * Allocate a new mm structure and copy contents from the - * mm structure of the passed in task structure. +/** + * dup_mm() - duplicates an existing mm structure + * @tsk: the task_struct with which the new mm will be associated. + * @oldmm: the mm to duplicate. + * + * Allocates a new mm structure and duplicates the provided @oldmm structure + * content into it. + * + * Return: the duplicated mm or NULL on failure. */ -static struct mm_struct *dup_mm(struct task_struct *tsk) +static struct mm_struct *dup_mm(struct task_struct *tsk, + struct mm_struct *oldmm) { - struct mm_struct *mm, *oldmm = current->mm; + struct mm_struct *mm; int err; mm = allocate_mm(); @@ -1372,7 +1379,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) } retval = -ENOMEM; - mm = dup_mm(tsk); + mm = dup_mm(tsk, current->mm); if (!mm) goto fail_nomem; @@ -2187,6 +2194,11 @@ struct task_struct *fork_idle(int cpu) return task; } +struct mm_struct *copy_init_mm(void) +{ + return dup_mm(NULL, &init_mm); +} + /* * Ok, this is the main fork-routine. *