ptrace, x86: fix the usage of ptrace_fork()
I noticed by pure accident we have ptrace_fork() and friends. This was added by "x86, bts: add fork and exit handling", commit bf53de90 . I can't test this, ds_request_bts() returns -EOPNOTSUPP, but I strongly believe this needs the fix. I think something like this program int main(void) { int pid = fork(); if (!pid) { ptrace(PTRACE_TRACEME, 0, NULL, NULL); kill(getpid(), SIGSTOP); fork(); } else { struct ptrace_bts_config bts = { .flags = PTRACE_BTS_O_ALLOC, .size = 4 * 4096, }; wait(NULL); ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEFORK); ptrace(PTRACE_BTS_CONFIG, pid, &bts, sizeof(bts)); ptrace(PTRACE_CONT, pid, NULL, NULL); sleep(1); } return 0; } should crash the kernel. If the task is traced by its natural parent ptrace_reparented() returns 0 but we should clear ->btsxxx anyway. Signed-off-by:Oleg Nesterov <oleg@redhat.com> Acked-by:
Markus Metzger <markus.t.metzger@intel.com> Signed-off-by:
Ingo Molnar <mingo@elte.hu>
parent
b52af409
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