Unverified Commit ab89060f authored by Luca Boccassi's avatar Luca Boccassi Committed by Christian Brauner
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pidfs: return -EREMOTE when PIDFD_GET_INFO is called on another ns 

Currently it is not possible to distinguish between the case where a
process has already exited and the case where a process is in a
different namespace, as both return -ESRCH.
glibc's pidfd_getpid() procfs-based implementation returns -EREMOTE
in the latter, so that distinguishing the two is possible, as the
fdinfo in procfs will list '0' as the PID in that case:

https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/pidfd_getpid.c;h=860829cf07da2267484299ccb02861822c0d07b4;hb=HEAD#l121



Change the error code so that the kernel also returns -EREMOTE in
that case.

Fixes: 7477d7dc ("pidfs: allow to retrieve exit information")

Signed-off-by: default avatarLuca Boccassi <luca.boccassi@gmail.com>
Link: https://patch.msgid.link/20260127225209.2293342-1-luca.boccassi@gmail.com


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent b3c78bc5

fs/pidfs.c

+1 −1
Original line number Diff line number Diff line
@@ -329,7 +329,7 @@ static long pidfd_info(struct file *file, unsigned int cmd, unsigned long arg) 
	 * namespace hierarchy.

	 */

	if (!pid_in_current_pidns(pid))

		return -ESRCH;

		return -EREMOTE;



	attr = READ_ONCE(pid->attr);

	if (mask & PIDFD_INFO_EXIT) {