From: Luca Boccassi 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: 7477d7dce48a ("pidfs: allow to retrieve exit information") Signed-off-by: Luca Boccassi --- More context: https://sourceware.org/pipermail/libc-alpha/2026-January/174506.html fs/pidfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/pidfs.c b/fs/pidfs.c index 1e20e36e0ed5..d18c51513f6c 100644 --- a/fs/pidfs.c +++ b/fs/pidfs.c @@ -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) { -- 2.47.3