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From: ebiederm@xmission.com (Eric W. Biederman)
To: Jeff Layton <jlayton@kernel.org>
Cc: viro@zeniv.linux.org.uk, berrange@redhat.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Oleg Nesterov <oleg@redhat.com>
Subject: [RFC][PATCH 1/3] exec: Move unshare_files down to avoid locks being dropped on exec.
Date: Sun, 16 Sep 2018 19:39:54 +0200	[thread overview]
Message-ID: <874leps5n9.fsf_-_@xmission.com> (raw)
In-Reply-To: <87a7ohs5ow.fsf@xmission.com> (Eric W. Biederman's message of "Sun, 16 Sep 2018 19:38:55 +0200")


Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 fs/exec.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 1ebf6e5a521d..6f6167ec08eb 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1252,6 +1252,7 @@ void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
  */
 int flush_old_exec(struct linux_binprm * bprm)
 {
+	struct files_struct *displaced;
 	int retval;
 
 	/*
@@ -1291,6 +1292,12 @@ int flush_old_exec(struct linux_binprm * bprm)
 	flush_thread();
 	current->personality &= ~bprm->per_clear;
 
+	retval = unshare_files(&displaced);
+	if (retval)
+		goto out;
+	if (displaced)
+		put_files_struct(displaced);
+
 	/*
 	 * We have to apply CLOEXEC before we change whether the process is
 	 * dumpable (in setup_new_exec) to avoid a race with a process in userspace
@@ -1713,7 +1720,6 @@ static int __do_execve_file(int fd, struct filename *filename,
 {
 	char *pathbuf = NULL;
 	struct linux_binprm *bprm;
-	struct files_struct *displaced;
 	int retval;
 
 	if (IS_ERR(filename))
@@ -1735,14 +1741,10 @@ static int __do_execve_file(int fd, struct filename *filename,
 	 * further execve() calls fail. */
 	current->flags &= ~PF_NPROC_EXCEEDED;
 
-	retval = unshare_files(&displaced);
-	if (retval)
-		goto out_ret;
-
 	retval = -ENOMEM;
 	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
 	if (!bprm)
-		goto out_files;
+		goto out_ret;
 
 	retval = prepare_bprm_creds(bprm);
 	if (retval)
@@ -1831,8 +1833,6 @@ static int __do_execve_file(int fd, struct filename *filename,
 	kfree(pathbuf);
 	if (filename)
 		putname(filename);
-	if (displaced)
-		put_files_struct(displaced);
 	return retval;
 
 out:
@@ -1849,9 +1849,6 @@ static int __do_execve_file(int fd, struct filename *filename,
 	free_bprm(bprm);
 	kfree(pathbuf);
 
-out_files:
-	if (displaced)
-		reset_files_struct(displaced);
 out_ret:
 	if (filename)
 		putname(filename);
-- 
2.17.1

  reply	other threads:[~2018-09-16 23:03 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-14 10:53 [PATCH v3 0/3] exec: fix passing of file locks across execve in multithreaded processes Jeff Layton
2018-09-14 10:53 ` [PATCH v3 1/3] exec: separate thread_count for files_struct Jeff Layton
2018-09-15 16:04   ` Oleg Nesterov
2018-09-16 16:10     ` Eric W. Biederman
2018-09-17 15:24       ` Oleg Nesterov
2018-09-17 20:45         ` Eric W. Biederman
2018-09-14 10:53 ` [PATCH v3 2/3] exec: delay clone(CLONE_FILES) if task associated with current files_struct is exec'ing Jeff Layton
2018-09-14 10:53 ` [PATCH v3 3/3] exec: do unshare_files after de_thread Jeff Layton
2018-09-15 16:37   ` Oleg Nesterov
2018-09-16 16:49     ` Eric W. Biederman
2018-09-17 15:28       ` Oleg Nesterov
2018-09-16 16:59   ` Eric W. Biederman
2018-09-16 17:38 ` [RFC][PATCH 0/3] exec: Moving unshare_files_struct Eric W. Biederman
2018-09-16 17:39   ` Eric W. Biederman [this message]
2018-09-17 15:49     ` [RFC][PATCH 1/3] exec: Move unshare_files down to avoid locks being dropped on exec Oleg Nesterov
2018-09-16 17:40   ` [RFC][PATCH 2/3] exec: Simplify unshare_files Eric W. Biederman
2018-09-17 16:23     ` Oleg Nesterov
2018-09-17 20:26       ` Eric W. Biederman
2018-09-16 17:41   ` [RFC][PATCH 3/3] exec: Remove reset_files_struct Eric W. Biederman
2018-09-17 15:59   ` [RFC][PATCH 0/3] exec: Moving unshare_files_struct Oleg Nesterov
2018-09-18 22:18     ` Eric W. Biederman
2018-09-17 16:24   ` Jeff Layton

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