[GIT PULL] exec fixes for v5.11-rc1

Eric W. Biederman
2020-12-15T23:01:26Z

Please pull the exec-for-v5.11 branch from the git tree:

git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git exec-for-v5.11

HEAD: 9ee1206dcfb9d56503c0de9f8320f7b29c795867 exec: Move io_uring_task_cancel after the point of no return

This set of changes ultimately fixes the interaction of posix file lock
and exec. Fundamentally most of the change is just moving where
unshare_files is called during exec, and tweaking the users of
files_struct so that the count of files_struct is not unnecessarily
played with.

Along the way fcheck and related helpers were renamed to more accurately
reflect what they do.

There were also many other small changes that fell out, as this is the
first time in a long time much of this code has been touched.

There is a minor conflict with parallel changes to the bpf task_iter
code. The changes don't fundamentally conflict but both are removing
code from same areas of the same function.

Benchmarks haven't turned up any practical issues but Al Viro has
observed a possibility for a lot of pounding on task_lock. So I have
some changes in progress to convert put_files_struct to always rcu free
files_struct. That wasn't ready for the merge window so that will have
to wait until next time.

Eric W. Biederman (28):
exec: Don't open code get_close_on_exec
exec: Move unshare_files to fix posix file locking during exec
exec: Simplify unshare_files
exec: Remove reset_files_struct
kcmp: In kcmp_epoll_target use fget_task
bpf: In bpf_task_fd_query use fget_task
proc/fd: In proc_fd_link use fget_task
file: Rename __fcheck_files to files_lookup_fd_raw
file: Factor files_lookup_fd_locked out of fcheck_files
file: Replace fcheck_files with files_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Implement task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
file: Implement task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In fdinfo seq_show don't use get_files_struct
file: Merge __fd_install into fd_install
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __alloc_fd into alloc_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Replace ksys_close with close_fd
file: Rename __close_fd_get_file close_fd_get_file
file: Remove get_files_struct
exec: Move unshare_files and guarantee files_struct.count is correct
coredump: Document coredump code exclusively used by cell spufs
exec: Move io_uring_task_cancel after the point of no return

Documentation/filesystems/files.rst | 8 +-
arch/powerpc/platforms/cell/spufs/coredump.c | 2 +-
drivers/android/binder.c | 2 +-
fs/autofs/dev-ioctl.c | 5 +-
fs/binfmt_elf.c | 2 +
fs/coredump.c | 6 +-
fs/exec.c | 39 ++++-----
fs/file.c | 124 +++++++++++++--------------
fs/io_uring.c | 2 +-
fs/locks.c | 14 +--
fs/notify/dnotify/dnotify.c | 2 +-
fs/open.c | 2 +-
fs/proc/fd.c | 48 ++++-------
include/linux/fdtable.h | 40 +++++----
include/linux/syscalls.h | 12 ---
kernel/bpf/syscall.c | 20 +----
kernel/bpf/task_iter.c | 44 +++-------
kernel/fork.c | 12 +--
kernel/kcmp.c | 29 ++-----
19 files changed, 161 insertions(+), 252 deletions(-)

Eric