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 2/3] exec: Simplify unshare_files
Date: Sun, 16 Sep 2018 19:40:43 +0200 [thread overview]
Message-ID: <87y3c1qr1g.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")
Now that exec calls unshare_files after the point of no return there
is no reason to return displaced.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/coredump.c | 5 +----
fs/exec.c | 5 +----
include/linux/fdtable.h | 2 +-
kernel/fork.c | 12 ++++++------
4 files changed, 9 insertions(+), 15 deletions(-)
diff --git a/fs/coredump.c b/fs/coredump.c
index 1e2c87acac9b..968ee5744bf9 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -546,7 +546,6 @@ void do_coredump(const siginfo_t *siginfo)
struct cred *cred;
int retval = 0;
int ispipe;
- struct files_struct *displaced;
/* require nonrelative corefile path and be extra careful */
bool need_suid_safe = false;
bool core_dumped = false;
@@ -747,11 +746,9 @@ void do_coredump(const siginfo_t *siginfo)
}
/* get us an unshared descriptor table; almost always a no-op */
- retval = unshare_files(&displaced);
+ retval = unshare_files();
if (retval)
goto close_fail;
- if (displaced)
- put_files_struct(displaced);
if (!dump_interrupted()) {
file_start_write(cprm.file);
core_dumped = binfmt->core_dump(&cprm);
diff --git a/fs/exec.c b/fs/exec.c
index 6f6167ec08eb..7eeffa7d98c6 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1252,7 +1252,6 @@ 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;
/*
@@ -1292,11 +1291,9 @@ int flush_old_exec(struct linux_binprm * bprm)
flush_thread();
current->personality &= ~bprm->per_clear;
- retval = unshare_files(&displaced);
+ retval = unshare_files();
if (retval)
goto out;
- if (displaced)
- put_files_struct(displaced);
/*
* We have to apply CLOEXEC before we change whether the process is
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index 41615f38bcff..e65379336c4c 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -108,7 +108,7 @@ struct task_struct;
struct files_struct *get_files_struct(struct task_struct *);
void put_files_struct(struct files_struct *fs);
void reset_files_struct(struct files_struct *);
-int unshare_files(struct files_struct **);
+int unshare_files(void);
struct files_struct *dup_fd(struct files_struct *, int *) __latent_entropy;
void do_close_on_exec(struct files_struct *);
int iterate_fd(struct files_struct *, unsigned,
diff --git a/kernel/fork.c b/kernel/fork.c
index d896e9ca38b0..a06a609075eb 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2564,21 +2564,21 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
* the exec layer of the kernel.
*/
-int unshare_files(struct files_struct **displaced)
+int unshare_files(void)
{
struct task_struct *task = current;
- struct files_struct *copy = NULL;
+ struct files_struct *files, *copy = NULL;
int error;
error = unshare_fd(CLONE_FILES, ©);
- if (error || !copy) {
- *displaced = NULL;
+ if (error || !copy)
return error;
- }
- *displaced = task->files;
+
+ files = task->files;
task_lock(task);
task->files = copy;
task_unlock(task);
+ put_files_struct(files);
return 0;
}
--
2.17.1
next prev parent reply other threads:[~2018-09-16 23:04 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 ` [RFC][PATCH 1/3] exec: Move unshare_files down to avoid locks being dropped on exec Eric W. Biederman
2018-09-17 15:49 ` Oleg Nesterov
2018-09-16 17:40 ` Eric W. Biederman [this message]
2018-09-17 16:23 ` [RFC][PATCH 2/3] exec: Simplify unshare_files 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87y3c1qr1g.fsf_-_@xmission.com \
--to=ebiederm@xmission.com \
--cc=berrange@redhat.com \
--cc=jlayton@kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).