Hi Ted, On 12/15/20 7:31 PM, Ted Estes wrote: > Per my research on the topic, the error is in the manual page. The > behavior of ptrace(2) was intentionally changed to prohibit attaching to > a thread in the same group. Apparently, there were a number of > ill-behaved edge cases. > > I found this email thread on the subject: > https://lkml.org/lkml/2006/8/31/241 Thank you for all the details and links! I'll fix the page. Thanks, Alex > > Thank you. > --Ted Estes > > On 12/15/2020 11:01 AM, Alejandro Colomar (man-pages) wrote: >> Hi, >> >> There's a bug report: https://bugzilla.kernel.org/show_bug.cgi?id=210655 >> >> [[ >> Under "Ptrace access mode checking", the documentation states: >> "1. If the calling thread and the target thread are in the same thread >> group, access is always allowed." >> >> This is incorrect. A thread may never attach to another in the same >> group. >> >> Reference, ptrace_attach() >> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/kernel/ptrace.c?h=v5.9.14#n380 >> >> ]] >> >> I just wanted to make sure that it is a bug in the manual page, and not >> in the implementation. >> >> >> Thanks, >> >> Alex >> > -- Alejandro Colomar Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es
