From 82c6dd20479bb6a9625e1d63a650c3be8865e2db Mon Sep 17 00:00:00 2001 From: AnonymeMeow Date: Sun, 7 Jun 2026 08:33:43 +0800 Subject: fanotify: allow reporting pidfds for reaped tasks Fanotify used to refuse to report pidfds for reaped tasks by applying a pid_has_task() check before calling pidfd_prepare(). This prevented userspace from obtaining information about the task. Register the event pid with pidfs when creating the fanotify event if pidfd reporting was requested, so pidfd_prepare() can later create a pidfd for the reaped task. Suggested-by: Christian Brauner Link: https://lore.kernel.org/linux-fsdevel/20260528-schmuckvoll-heilen-garen-be77b4208671@brauner/ Signed-off-by: AnonymeMeow Signed-off-by: Christian Brauner (Amutable) Link: https://patch.msgid.link/20260607003343.425939-3-anonymemeow@gmail.com Signed-off-by: Jan Kara --- include/linux/pidfs.h | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/pidfs.h b/include/linux/pidfs.h index 416bdff4d6ce..0abf7da9ab23 100644 --- a/include/linux/pidfs.h +++ b/include/linux/pidfs.h @@ -2,6 +2,8 @@ #ifndef _LINUX_PID_FS_H #define _LINUX_PID_FS_H +#include + struct coredump_params; struct file *pidfs_alloc_file(struct pid *pid, unsigned int flags); @@ -14,7 +16,21 @@ void pidfs_exit(struct task_struct *tsk); void pidfs_coredump(const struct coredump_params *cprm); #endif extern const struct dentry_operations pidfs_dentry_operations; -int pidfs_register_pid(struct pid *pid); +int pidfs_register_pid_gfp(struct pid *pid, gfp_t gfp); + +/** + * pidfs_register_pid - register a struct pid in pidfs + * @pid: pid to pin + * + * Register a struct pid in pidfs. + * + * Return: On success zero, on error a negative error code is returned. + */ +static inline int pidfs_register_pid(struct pid *pid) +{ + return pidfs_register_pid_gfp(pid, GFP_KERNEL); +} + void pidfs_free_pid(struct pid *pid); #endif /* _LINUX_PID_FS_H */ -- cgit v1.2.3