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authorLinus Torvalds <torvalds@linux-foundation.org>2019-06-28 00:41:18 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2019-06-28 00:41:18 (GMT)
commit7a702b4e82d8730d6964bfd98b3b024c126e9846 (patch)
treeeb8a7c06d77d4f2f740c45d6a9b8910f0a1611c6 /fs
parent763cf1f2d9bfc8349c5791689074c8c17edf660d (diff)
parent30d158b143b6575261ab610ae7b1b4f7fe3830b3 (diff)
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Merge tag 'for-linus-20190627' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux
Pull pidfd fixes from Christian Brauner: "Userspace tools and libraries such as strace or glibc need a cheap and reliable way to tell whether CLONE_PIDFD is supported. The easiest way is to pass an invalid fd value in the return argument, perform the syscall and verify the value in the return argument has been changed to a valid fd. However, if CLONE_PIDFD is specified we currently check if pidfd == 0 and return EINVAL if not. The check for pidfd == 0 was originally added to enable us to abuse the return argument for passing additional flags along with CLONE_PIDFD in the future. However, extending legacy clone this way would be a terrible idea and with clone3 on the horizon and the ability to reuse CLONE_DETACHED with CLONE_PIDFD there's no real need for this clutch. So remove the pidfd == 0 check and help userspace out. Also, accordig to Al, anon_inode_getfd() should only be used past the point of no failure and ksys_close() should not be used at all since it is far too easy to get wrong. Al's motto being "basically, once it's in descriptor table, it's out of your control". So Al's patch switches back to what we already had in v1 of the original patchset and uses a anon_inode_getfile() + put_user() + fd_install() sequence in the success path and a fput() + put_unused_fd() in the failure path. The other two changes should be trivial" * tag 'for-linus-20190627' of gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux: proc: remove useless d_is_dir() check copy_process(): don't use ksys_close() on cleanups samples: make pidfd-metadata fail gracefully on older kernels fork: don't check parent_tidptr with CLONE_PIDFD
Diffstat (limited to 'fs')
-rw-r--r--fs/proc/base.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9c8ca6c..255f675 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3077,8 +3077,7 @@ static const struct file_operations proc_tgid_base_operations = {
struct pid *tgid_pidfd_to_pid(const struct file *file)
{
- if (!d_is_dir(file->f_path.dentry) ||
- (file->f_op != &proc_tgid_base_operations))
+ if (file->f_op != &proc_tgid_base_operations)
return ERR_PTR(-EBADF);
return proc_pid(file_inode(file));