On Wed, Oct 31, 2018 at 03:06:22PM +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 is missing. > --- > Documentation/filesystems/proc.txt | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt > index 12a5e6e693b6..567f66a8a23c 100644 > --- a/Documentation/filesystems/proc.txt > +++ b/Documentation/filesystems/proc.txt > @@ -214,6 +214,14 @@ asynchronous manner and the value may not be very precise. To see a precise > snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table. > It's slow but very precise. > > +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. > + I'd put this text in the beginning of the section, just before table 1-1. Otherwise looks good. It maybe also useful to update 'man 5 proc' (1) as well [1] https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/man5/proc.5 > Table 1-2: Contents of the status files (as of 4.8) > .............................................................................. > Field Content > -- > 2.19.1.568.g152ad8e336-goog > -- Sincerely yours, Mike.
