On Mon, Nov 05, 2018 at 01:22:05PM +0000, Daniel Colascione wrote: > State explicitly that holding a /proc/pid file descriptor open does > not reserve the PID. Also note that in the event of PID reuse, these > open file descriptors refer to the old, now-dead process, and not the > new one that happens to be named the same numeric PID. > > Signed-off-by: Daniel Colascione <dancol@xxxxxxxxxx> Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> > --- > Documentation/filesystems/proc.txt | 7 +++++++ > 1 file changed, 7 insertions(+) > > Moved paragraphed to start of /proc/pid section; added signed-off-by. > > diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt > index 12a5e6e693b6..0b14460f721d 100644 > --- a/Documentation/filesystems/proc.txt > +++ b/Documentation/filesystems/proc.txt > @@ -125,6 +125,13 @@ process running on the system, which is named after the process ID (PID). > The link self points to the process reading the file system. Each process > subdirectory has the entries listed in Table 1-1. > > +Note that an open a file descriptor to /proc/<pid> or to any of its > +contained files or subdirectories does not prevent <pid> being reused > +for some other process in the event that <pid> exits. Operations on > +open /proc/<pid> file descriptors corresponding to dead processes > +never act on any new process that the kernel may, through chance, have > +also assigned the process ID <pid>. Instead, operations on these FDs > +usually fail with ESRCH. > > Table 1-1: Process specific entries in /proc > .............................................................................. > -- > 2.19.1.930.g4563a0d9d0-goog > -- Sincerely yours, Mike.
