This is a note to let you know that I've just added the patch titled fs: provide locked helper variant of close_fd_get_file() to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: fs-provide-locked-helper-variant-of-close_fd_get_file.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 369d83e272a9f1a316ce79b1236f1f3265e40efe Mon Sep 17 00:00:00 2001 From: Jens Axboe <axboe@xxxxxxxxx> Date: Tue, 19 Jan 2021 15:41:52 -0700 Subject: fs: provide locked helper variant of close_fd_get_file() From: Jens Axboe <axboe@xxxxxxxxx> [ Upstream commit 53dec2ea74f2ef360e8455439be96a780baa6097 ] Assumes current->files->file_lock is already held on invocation. Helps the caller check the file before removing the fd, if it needs to. Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/file.c | 36 +++++++++++++++++++++++++----------- fs/internal.h | 1 + 2 files changed, 26 insertions(+), 11 deletions(-) --- a/fs/file.c +++ b/fs/file.c @@ -22,6 +22,8 @@ #include <linux/close_range.h> #include <net/sock.h> +#include "internal.h" + unsigned int sysctl_nr_open __read_mostly = 1024*1024; unsigned int sysctl_nr_open_min = BITS_PER_LONG; /* our min() is unusable in constant expressions ;-/ */ @@ -780,36 +782,48 @@ int __close_range(unsigned fd, unsigned } /* - * variant of close_fd that gets a ref on the file for later fput. - * The caller must ensure that filp_close() called on the file, and then - * an fput(). + * See close_fd_get_file() below, this variant assumes current->files->file_lock + * is held. */ -int close_fd_get_file(unsigned int fd, struct file **res) +int __close_fd_get_file(unsigned int fd, struct file **res) { struct files_struct *files = current->files; struct file *file; struct fdtable *fdt; - spin_lock(&files->file_lock); fdt = files_fdtable(files); if (fd >= fdt->max_fds) - goto out_unlock; + goto out_err; file = fdt->fd[fd]; if (!file) - goto out_unlock; + goto out_err; rcu_assign_pointer(fdt->fd[fd], NULL); __put_unused_fd(files, fd); - spin_unlock(&files->file_lock); get_file(file); *res = file; return 0; - -out_unlock: - spin_unlock(&files->file_lock); +out_err: *res = NULL; return -ENOENT; } +/* + * variant of close_fd that gets a ref on the file for later fput. + * The caller must ensure that filp_close() called on the file, and then + * an fput(). + */ +int close_fd_get_file(unsigned int fd, struct file **res) +{ + struct files_struct *files = current->files; + int ret; + + spin_lock(&files->file_lock); + ret = __close_fd_get_file(fd, res); + spin_unlock(&files->file_lock); + + return ret; +} + void do_close_on_exec(struct files_struct *files) { unsigned i; --- a/fs/internal.h +++ b/fs/internal.h @@ -134,6 +134,7 @@ extern struct file *do_file_open_root(st const char *, const struct open_flags *); extern struct open_how build_open_how(int flags, umode_t mode); extern int build_open_flags(const struct open_how *how, struct open_flags *op); +extern int __close_fd_get_file(unsigned int fd, struct file **res); long do_sys_ftruncate(unsigned int fd, loff_t length, int small); int chmod_common(const struct path *path, umode_t mode); Patches currently in stable-queue which might be from axboe@xxxxxxxxx are queue-5.10/x86-process-setup-io_threads-more-like-normal-user-space-threads.patch queue-5.10/powerpc-add-support-for-tif_notify_signal.patch queue-5.10/eventfd-provide-a-eventfd_signal_mask-helper.patch queue-5.10/fs-provide-locked-helper-variant-of-close_fd_get_file.patch queue-5.10/relay-fix-type-mismatch-when-allocating-memory-in-re.patch queue-5.10/eventfd-change-int-to-__u64-in-eventfd_signal-ifndef.patch queue-5.10/io_uring-pass-in-epoll_uring_wake-for-eventfd-signaling-and-wakeups.patch queue-5.10/blk-mq-fix-possible-memleak-when-register-hctx-faile.patch queue-5.10/fix-handling-of-nd-depth-on-lookup_cached-failures-in-try_to_unlazy.patch queue-5.10/net-provide-__sys_shutdown_sock-that-takes-a-socket.patch queue-5.10/task_work-unconditionally-run-task_work-from-get_signal.patch queue-5.10/openrisc-add-support-for-tif_notify_signal.patch queue-5.10/signal-add-task_sigpending-helper.patch queue-5.10/net-remove-cmsg-restriction-from-io_uring-based-send-recvmsg-calls.patch queue-5.10/alpha-add-support-for-tif_notify_signal.patch queue-5.10/nios32-add-support-for-tif_notify_signal.patch queue-5.10/ia64-don-t-call-handle_signal-unless-there-s-actually-a-signal-queued.patch queue-5.10/task_work-remove-legacy-twa_signal-path.patch queue-5.10/revert-proc-don-t-allow-async-path-resolution-of-proc-self-components.patch queue-5.10/m68k-add-support-for-tif_notify_signal.patch queue-5.10/s390-add-support-for-tif_notify_signal.patch queue-5.10/um-add-support-for-tif_notify_signal.patch queue-5.10/tools-headers-uapi-sync-openat2.h-with-the-kernel-sources.patch queue-5.10/kernel-provide-create_io_thread-helper.patch queue-5.10/iov_iter-add-helper-to-save-iov_iter-state.patch queue-5.10/arc-unbork-5.11-bootup-fix-snafu-in-_tif_notify_signal-handling.patch queue-5.10/arch-ensure-parisc-powerpc-handle-pf_io_worker-in-copy_thread.patch queue-5.10/csky-add-support-for-tif_notify_signal.patch queue-5.10/arm-add-support-for-tif_notify_signal.patch queue-5.10/kernel-stop-masking-signals-in-create_io_thread.patch queue-5.10/fs-expose-lookup_cached-through-openat2-resolve_cached.patch queue-5.10/task_work-add-helper-for-more-targeted-task_work-canceling.patch queue-5.10/nds32-add-support-for-tif_notify_signal.patch queue-5.10/signal-kill-jobctl_task_work.patch queue-5.10/hexagon-add-support-for-tif_notify_signal.patch queue-5.10/sh-add-support-for-tif_notify_signal.patch queue-5.10/riscv-add-support-for-tif_notify_signal.patch queue-5.10/h8300-add-support-for-tif_notify_signal.patch queue-5.10/io_uring-import-5.15-stable-io_uring.patch queue-5.10/sparc-add-support-for-tif_notify_signal.patch queue-5.10/blktrace-fix-output-non-blktrace-event-when-blk_clas.patch queue-5.10/eventpoll-add-epoll_uring_wake-poll-wakeup-flag.patch queue-5.10/parisc-add-support-for-tif_notify_signal.patch queue-5.10/entry-add-support-for-tif_notify_signal.patch queue-5.10/x86-wire-up-tif_notify_signal.patch queue-5.10/task_work-use-tif_notify_signal-if-available.patch queue-5.10/drbd-fix-an-invalid-memory-access-caused-by-incorrec.patch queue-5.10/kernel-don-t-call-do_exit-for-pf_io_worker-threads.patch queue-5.10/kernel-allow-fork-with-tif_notify_signal-pending.patch queue-5.10/pata_ipx4xx_cf-fix-unsigned-comparison-with-less-tha.patch queue-5.10/mips-add-support-for-tif_notify_signal.patch queue-5.10/xtensa-add-support-for-tif_notify_signal.patch queue-5.10/c6x-add-support-for-tif_notify_signal.patch queue-5.10/microblaze-add-support-for-tif_notify_signal.patch queue-5.10/net-add-accept-helper-not-installing-fd.patch queue-5.10/ia64-add-support-for-tif_notify_signal.patch queue-5.10/arm64-add-support-for-tif_notify_signal.patch queue-5.10/arc-add-support-for-tif_notify_signal.patch queue-5.10/revert-proc-don-t-allow-async-path-resolution-of-proc-thread-self-components.patch queue-5.10/fs-make-do_renameat2-take-struct-filename.patch queue-5.10/kernel-remove-checking-for-tif_notify_signal.patch queue-5.10/arch-setup-pf_io_worker-threads-like-pf_kthread.patch queue-5.10/nvme-pci-fix-mempool-alloc-size.patch queue-5.10/fs-add-support-for-lookup_cached.patch